DAR File No. 39821
This rule was published in the November 1, 2015, issue (Vol. 2015, No. 21) of the Utah State Bulletin.
Environmental Quality, Water Quality
Rule R317-4
Onsite Wastewater Systems
Notice of Proposed Rule
(Amendment)
DAR File No.: 39821
Filed: 10/13/2015 02:51:16 PM
RULE ANALYSIS
Purpose of the rule or reason for the change:
The reason for this amendment is an updating or fine-tuning of the rule after a major revision enacted in September 2013.
Summary of the rule or change:
The changes include formatting clarifications, some minor onsite system design changes, and some minor changes to the percolation test procedures.
State statutory or constitutional authorization for this rule:
- Section 19-5-104
Anticipated cost or savings to:
the state budget:
These changes will not result in any change in work load for state staff working in this area.
local governments:
There should be no anticipated cost to local government. These changes may result in a very slight savings to local government by slightly reducing the burden of percolation test requirements in certain situations, where local government performs those tests.
small businesses:
Like with local government above, no measurable costs or savings should be realized as a result of these changes, but they may result in a very slight savings to small businesses by slightly reducing the burden of percolation test requirements in certain situations, where small businesses perform those tests.
persons other than small businesses, businesses, or local governmental entities:
These changes may result in a very slight savings to other persons by slightly reducing the burden of percolation test requirements in certain situations, where other persons may perform those tests. There is no measurable amount that can be specified.
Compliance costs for affected persons:
These changes may result in other cost savings to the regulated community by enacting slight relaxations in the requirements for designing septic systems, but there are no changes in compliance costs.
Comments by the department head on the fiscal impact the rule may have on businesses:
I see no fiscal impact on businesses due to these changes since they are mostly minor adjustments to the soil testing procedures. This may allow septic systems to be installed on properties that did not previously allow development, but the change is very small and the impact will probably be imperceptible.
Alan Matheson, Executive Director
The full text of this rule may be inspected, during regular business hours, at the Division of Administrative Rules, or at:
Environmental QualityWater QualityRoom DEQ, Third Floor
195 N 1950 W
SALT LAKE CITY, UT 84116
Direct questions regarding this rule to:
- Judy Etherington at the above address, by phone at 801-536-4344, by FAX at 801-536-4301, or by Internet E-mail at jetherington@utah.gov
Interested persons may present their views on this rule by submitting written comments to the address above no later than 5:00 p.m. on:
12/01/2015
This rule may become effective on:
12/08/2015
Authorized by:
Walter Baker, Director
RULE TEXT
R317. Environmental Quality, Water Quality.
R317-4. Onsite Wastewater Systems.
R317-4-1. Authority, Purpose, Scope, and Administrative Requirements.
1.1 Authorization.
These rules are administered by the division authorized by Title 19 Chapter 5.
1.2. Purpose.
The purpose of this rule is to protect the public health and environment from potential adverse effects from onsite wastewater disposal within the boundaries of Utah.
1.3. Scope.
This rule shall apply to onsite wastewater systems.
1.4. Jurisdiction.
Local health departments have jurisdiction to administer this rule. Nothing contained in this rule shall be construed to prevent local health departments from:
A. adopting stricter requirements than those contained herein;
B. issuing an operating permit, with[at] a
term[frequency] not exceeding [once every ]five years
, with an inspection showing a satisfactory performance of
the permitted system by the department's staff before
renewal;
C. taking necessary steps for ground water quality protection:
1. through adoption of a ground water quality protection management policy based on a ground water management study; or
2. by an onsite wastewater systems management planning policy and land use planning through the county's agency;
D. prohibiting any alternative system within its jurisdiction;
E. assessing fees for administration of this rule;
F. requiring the onsite systems within its jurisdiction be placed under an umbrella of a:
1. responsible management entity overseen by the local health department;
2. contract service provider overseen by the local health department; or
3. management district body politic created by the county for the purpose of operation, maintenance, repairs and monitoring of alternative or all onsite wastewater systems;
G. requiring conventional and alternative systems to be serviced; and
H. receiving a request for a variance, conducting a review, and granting either an approval or denial.
1.5. Alternative System Administration.
Local health departments shall administer an alternative systems program.
A. The local board of health may restrict its administration of these systems by notifying the division that it is exempt from this requirement by:
1. adopting a resolution or regulation; or
2. presenting an ordinance.
B. An alternative systems program shall:
1. advise the owner of the:
a. type of alternative system;
b. information concerning risk of failure;
c. level of maintenance required;
d. financial liability for repair, modification or replacement of a failed system; and
e. periodic monitoring requirements;
2. ensure that a Notice of the existence of the alternative system is recorded in the chain of title for that property;
3. provide oversight of installed alternative systems;
4. inspect all installed alternative systems at frequency specified in this rule, through:
a. the department's staff;
b. contracted service providers;
c. responsible management entities;
d. a management district body politic created by the county for the purpose of managing onsite wastewater systems; or
e. any combination of the above options;
5. maintain records of all installed alternative systems, failures, modifications, repairs and all inspections, recording the condition of the system at the time of inspection, such as overflow, surfacing, ponding, and nuisance;
6. submit an annual report to the division on or before September 1 for the previous state of Utah fiscal year's activities showing:
a. the type and number of alternative systems approved, installed, modified, repaired, failed, and inspected;
b. a summary of enforcement actions taken, pending and resolved; and
c. a summary of performance of water quality data collected;
7. require all alternative systems to be inspected and serviced as detailed in Section R317-4-13 Table 7 and Section R317-4-11.
1.6. Variance Administration Authority.
The Water Quality Board delegates the authority to grant or deny variances to the design requirements provided for in this rule to the local health departments. The board may amend, suspend, or rescind this delegation of authority to a local health department if it is determined that the local health department is not accepting or conducting reviews as described in Section R317-4-12.
A. The local health department having jurisdiction shall accept applications for variance requests on lots that are deemed not feasible for permitting an onsite wastewater system. Upon completion of a review, the local health department will grant or deny a variance to this rule as outlined in Section R317-4-12. The local health department also will submit an annual report of completed variance determinations to the division.
B. If a local health department fails to evaluate variance requests according to Section R317-4-12, the director shall notify the local health department. The director on behalf of the board may thereafter amend, suspend, or rescind the delegation of variance authority to the local health department. The variance authority would then revert to the division, and requests will be reviewed as follows.
1. The director may appoint a variance advisory committee to consider variance requests and make recommendations to the director. Any such advisory committee shall include at least one representative from a local health department. The director may refer any variance request to the variance advisory committee.
2. Upon review of the recommendation submitted by the variance advisory committee, the director shall render a written determination of the requested variance. If no committee was appointed by the director, the director shall render a written determination. Written determinations must be given within 180 days of the receipt of a complete and technically adequate variance request.
3. The director's final written determination will be forwarded to the local health department that has jurisdiction. The local health department is not required to approve or deny an operating or construction permit based on the director's determination of a variance request.
R317-4-2. Definitions.
"Absorption area" means the entire area used for the subsurface treatment and dispersion of effluent by an absorption system.
"Absorption bed" means an absorption system consisting of large excavated areas utilizing drain media or chambers.
"Absorption system" means a covered system constructed to receive and to disperse effluent, from gravity or a pump, in such a manner that the effluent is effectively filtered and retained below the ground surface.
"Absorption trench" means an absorption system consisting of a series of narrow excavated trenches utilizing drain media, chambers, or bundled synthetic aggregate units.
"Alternative onsite wastewater system" means an onsite wastewater system that is not a conventional onsite wastewater system.
"At-grade system" means an alternative onsite wastewater system where the bottom of the absorption system is placed at or below the elevation of the existing site grade, and the top of the distribution pipe is above the elevation of existing site grade, and the absorption system is contained within fill that extends above that grade.
"Barrier material" means an effective, pervious material such as an acceptable synthetic filter fabric, or a two-inch layer of compacted straw.
"Bedrock" means the rock, usually solid, that underlies soil or other unconsolidated, superficial material.
"Bedroom" means any portion of a dwelling that is so designed as to furnish the minimum isolation necessary for use as a sleeping area. It may include a den, study, sewing room, or sleeping loft. Unfinished basements shall be counted as a minimum of one additional bedroom.
"Board" means the Utah Water Quality Board.
"Body politic" means the state or its agencies or any political subdivision of the state to include a county, city, town, improvement district, taxing district or other governmental subdivision or public corporation of the state.
"Building sewer" means the pipe that carries wastewater from the building to a public sewer, an onsite wastewater system or other point of dispersal. It is synonymous with "house sewer".
"Bundled synthetic aggregate trench" means an absorption trench utilizing bundled synthetic aggregate units.
"Bundled synthetic aggregate unit" means a cylindrically shaped manufactured unit of synthetic aggregate enclosed in polyolefin netting, which may contain a perforated pipe.
"Chamber" means an open bottom, chambered structure of an approved material and design.
"Chambered trench" means an absorption trench utilizing chambers.
"Cleanout" means a device designed to provide access for removal of deposited or accumulated materials, generally from a pipe.
"Closed loop distribution" means a distribution method where the absorption system layout has the inlet and outlet ends of each lateral connected creating a complete and continuous pathway for effluent flow.
"Coarse drain media" means drain media ranging from 3/4 to 12 inches in diameter.
"Condominium" means the ownership of a single unit in a multi-unit project together with an undivided interest in common, in the common areas and facilities of the property.
"Connecting trench" means an absorption trench that is used to connect other absorption trenches, is less than 20 feet in length, and may be used to calculate total required absorption area.
"Construction permit" means the permit that authorizes an onsite wastewater system to be installed according to an approved design. An additional construction permit may also authorize activities associated with the repair or alteration of a malfunctioning or failing system.
"Conventional onsite wastewater system" means an onsite wastewater system typically consisting of a building sewer, a septic tank, and an absorption system utilizing absorption trenches, absorption beds, deep wall trenches, or seepage pits.
"Cover" means soils used to overlay the absorption area that is free of large stones 10 inches diameter or larger, frozen clumps of earth, masonry, stumps, or waste construction material, or other materials that could damage the system.
"Curtain drain" means any ground water interceptor or drainage system that is backfilled with gravel or other suitable material and is intended to interrupt or divert the course of shallow ground water or surface water away from the onsite wastewater system.
"Designer" means a person who fulfills the requirements of Rule R317-11.
"Deep wall trench" means an absorption system consisting of deep excavated trenches utilizing coarse drain media, with a minimum sidewall absorption depth of 24 inches of suitable soil formation below the distribution pipe.
"Director" means the director of the Division of Water Quality or, for purposes of groundwater quality at a facility licensed by and under the Division of Radiation Control, the director of the Division of Radiation Control.
"Distribution box" means a watertight structure that receives effluent and distributes it concurrently, in essentially equal portions, into two or more pipes leading to an absorption system.
"Distribution pipe" means an approved pipe, solid or perforated, used in the dispersion of effluent in an absorption system.
"Diversion valve" means a watertight structure that receives effluent through one inlet and distributes it to two or more outlets, only one of which is used at a time.
"Division" means the Utah Division of Water Quality.
"Domestic wastewater" means a combination of the liquid or water-carried wastes from residences, business buildings, institutions, and other establishments with installed plumbing facilities, excluding non-domestic wastewater. It is synonymous with the term "sewage".
"Drain media" means media used in an absorption system. It shall consist of stone, crushed stone, or gravel, ranging from 3/4 to 2-1/2 inches in diameter. It shall be free from fines, dust, sand or organic material and shall be durable and inert so that it will maintain its integrity, will not collapse or disintegrate with time. The maximum fines in the media shall be 2% by weight passing through a US Standard #10 mesh or 2 millimeter sieve. It shall be protected by a barrier material.
"Drainage system" means all the piping within public or private premises that conveys sewage or other liquid wastes to a legal point of treatment and dispersal, but does not include the mains of a public sewer system or a public sewage treatment or disposal plant.
"Drop box" means a watertight structure that receives septic tank effluent and distributes it into one or more distribution pipes, and into an overflow leading to another drop box and absorption system located at a lower elevation.
"Dry wash" means the dry bed of an ephemeral stream that flows only after heavy rains and is often found at the bottom of a canyon.
"Dwelling" means any structure, building, or any portion thereof that is used, intended, or designed to be occupied for human living purposes including houses, mobile homes, hotels, motels, and apartments.
"Effluent" means the liquid discharge from any treatment unit including a septic tank.
"Effluent pump" means a pump used to lift effluent.
"Effluent sewer" means solid pipe that carries effluent to the absorption system.
"Ejector pump" means a device to elevate or pump sewage to a septic tank, public sewer, or other means of disposal.
"Ephemeral stream" means a stream that flows for a small period of time, a week or less, after a precipitation event.
"Excessively permeable soil" means soils having an excessively high permeability, such as cobbles or gravels with little fines and large voids, and having a percolation rate faster than 1 minute per inch.
"Experimental onsite wastewater system" means an onsite wastewater treatment and absorption system that is still in experimental use and requires further testing in order to provide sufficient information to determine its acceptance.
"Filter fabric" means a synthetic, non-degradable woven or spun-bonded sheet material that has adequate tensile strength to prevent ripping during installation and backfilling, adequate permeability to allow free passage of water and gases; and adequate particle retention to prevent downward migration of soil particles into the absorption system. The minimum physical properties for the fabric shall be 4.0 ounces per square yard or equivalent.
"Ground water" means that portion of subsurface water that is in the zone of soil saturation.
"Ground water table" means the surface of a body of unconfined ground water in which the pressure is equal to that of the atmosphere.
"Ground water table, perched"
means unconfined ground water separated from an underlying body of
ground water by an unsaturated zone. [Its water table is a perched water table. ]It is
underlain by a restrictive strata or impervious layer. Perched
ground water may be either permanent, where recharge is frequent
enough to maintain a saturated zone above the perching bed, or
temporary, where intermittent recharge is not great or frequent
enough to prevent the perched water from disappearing from time to
time as a result of drainage over the edge of or through the
perching bed.
"Gulch" means a small rocky ravine or a narrow gorge, especially one with an ephemeral stream running through it.
"Gully" means a channel or small valley, especially one carved out by persistent heavy rainfall or an ephemeral stream.
"Impervious strata" means a layer that prevents water or root penetration. In addition, it shall be defined as unsuitable soils or soils having a percolation rate slower than 60 minutes per inch for conventional systems.
"Installer" means a qualified person with an appropriate contractor's license and knowledgeable in the installation or repair of an onsite wastewater system or its components.
"Intermittent stream" means a stream that flows for a period longer than an ephemeral stream on a seasonal basis or after a precipitation event.
"Invert" means the lowest portion of the internal cross section of a pipe or fitting.
"Lateral" means a length of distribution pipe or chambered trenches in the absorption system.
"Local health department" means a county or multi-county local health department established under Title 26A.
"Lot" means a portion of a subdivision, or any other parcel of land intended as a unit for transfer of ownership or for development or both and may not include any part of the right-of-way of a street or road.
"Malfunctioning or failing system" means an onsite wastewater system that is not functioning in compliance with the requirements of this regulation and may include:
A. absorption systems that seep or flow to the surface of the ground or into waters of the state;
B. systems that overflow from any of their components;
C. systems that, due to failure to operate in accordance with their designed operation, cause backflow into any portion of a building drainage system;
D. systems discharging effluent that does not comply with applicable effluent discharge standards;
E. leaking septic tanks; or
F. noncompliance with standards stipulated on or by the construction permit, operating permit, or both.
"Maximum ground water table" means the highest elevation that the top of the "ground water table" or "ground water table, perched" is expected to reach for any reason over the full operating life of the onsite wastewater system at that site.
"May" means discretionary, permissive, or allowed.
"Mound system" means an alternative onsite wastewater system where the bottom of the absorption system is placed above the elevation of the original site, and the absorption system is contained in a mounded fill body above that grade.
"Non-closed loop distribution" means a distribution method where the absorption system layout has lateral ends that are not connected.
"Non-domestic effluent" means the liquid discharge from any treatment unit including a septic tank that has a BOD5 equal or greater than 250 mg/L; or TSS equal to or greater than 145 mg/L; or fats, oils, and grease equal to or greater than 25 mg/L.
"Non-domestic wastewater" means process wastewater originating from the manufacture of specific products. Such wastewater is usually more concentrated, more variable in content and rate, and requires more extensive or different treatment than domestic wastewater.
"Non-public water source" means a culinary water source that is not defined as a public water source.
"Non-residential" means a building that produces domestic wastewater, and is not a single family dwelling.
"Onsite wastewater system" means an underground wastewater dispersal system that is designed for a capacity of 5,000 gallons per day or less, and is not designed to serve multiple dwelling units that are owned by separate owners except condominiums. It usually consists of a building sewer, a septic tank and an absorption system.
"Operating permit" means the permit that authorizes the operation and maintenance of an onsite wastewater system or wastewater holding tank. It may have a fee component that requires periodic renewal.
"Packed bed media system" means an alternative onsite wastewater system that uses natural or synthetic media to treat wastewater. Biological treatment is facilitated via microbial growth on the surface of the media. The system may include a pump tank, a recirculation tank, or both.
"Percolation rate" means the time expressed in minutes per inch required for water to seep into saturated soil at a constant rate during a percolation test.
"Percolation test" means the method used to measure the permeability of the soil by measuring the percolation rate as described in these rules. This is sometimes referred to as a "perc test".
"Permeability" means the rate at which a soil transmits water when saturated.
"Person" means an individual, trust, firm, estate, company, corporation, partnership, association, state, state or federal agency or entity, municipality, commission, or political subdivision of a state as defined in Section 19-1-103.
"Pollution" means any man-made or man-induced alteration of the chemical, physical, biological, or radiological integrity of any waters of the state, unless the alteration is necessary for public health and safety as defined in Section 19-5-102.
"Pressure distribution" means a method designed to uniformly distribute effluent under pressure within an absorption system.
"Public health hazard" means, for the purpose of this rule, a condition whereby there are sufficient types and amounts of biological, chemical, or physical agents relating to water or sewage that are likely to cause human illness, disorders or disability. These may include pathogenic viruses and bacteria, parasites, toxic chemicals and radioactive isotopes. A malfunctioning onsite wastewater system constitutes a public health hazard.
"Public water source" means a culinary water source, either publicly or privately owned, providing water for human consumption and other domestic uses, as defined in Title R309.
"Pump tank" means a watertight receptacle equipped with a pump and placed after a septic tank or other treatment component.
"Pump vault" means a device installed in a septic or pump tank that houses a pump and screens effluent with 1/8 inch openings or smaller before it enters the pump.
"Recirculation tank" means the tank that receives, stores, and recycles partially treated effluent and recycles that effluent back through the treatment process or to the absorption area.
"Regulatory authority" means either the Utah Division of Water Quality or the local health department having jurisdiction.
"Replacement area" means sufficient land with suitable soil, excluding streets, roads, easements and permanent structures that complies with the setback requirements of these rules, and is intended for the 100% replacement of absorption systems.
"Rotary tilling" means a tillage operation. Working land by plowing and harrowing in order to make land ready for cultivation, or employing power driven rotary motion of the tillage tool to loosen, shatter and mix soil.
"Sand lined trench system" means an alternative onsite wastewater system consisting of a series of narrow excavated trenches utilizing sand media and pressure distribution.
"Sand media" means sand fill meeting the ASTM C33/C33M - 11A Standard Specification for Concrete Aggregates.
"Saprolite" means weathered material underlying the soil that grades from soft thoroughly decomposed rock to rock that has been weathered sufficiently so that it can be broken in the hands, cut with a knife or easily dug with a backhoe and is devoid of expansive clay. It has rock structure instead of soil structure and does not include hard bedrock or hard fractured bedrock.
"Scarification" means loosening and breaking up of soil compaction in a manner that prevents smearing and maintains soil structure.
"Scum" means a mass of sewage solids, which is buoyed up by entrained gas, grease, or other substances, floating on the surface of wastes in a septic tank.
"Seepage pit" means an absorption system consisting of one or more deep excavated pits, either hollow-lined or filled, utilizing coarse drain media, with a minimum sidewall absorption depth of 48 inches of suitable soil formation below the distribution pipe.
"Septage" means the semi-liquid material that is pumped out of a septic or pump tank, generally consisting of the sludge, liquid, and scum layer.
"Septic tank" means a watertight receptacle that receives the discharge of a drainage system or part thereof, designed and constructed so as to retain solids, digest organic matter through a period of detention and allow the liquids to discharge into the soil outside of the tank through an absorption system.
"Sequential distribution" means a distribution method in which effluent does not pass through an absorption area before it enters the succeeding areas through a distribution box or relief line allowing for portions of the absorption area to be isolated.
"Serial distribution" means a distribution method in which effluent passes through an absorption area before entering the succeeding areas through a distribution box or relief line creating a single uninterrupted flow path.
"Shall" means a mandatory requirement.
"Should" means recommended or preferred and is intended to mean a desirable standard.
"Single-family dwelling" means a building designed to be used as a home by the owner or lessee of such building.
"Sludge" means the accumulation of solids that have settled in a septic tank or a wastewater holding tank.
"Slope" means the ratio of the rise divided by the run between two points, typically described as a percentage (rise divided by run multiplied by 100).
"Soil exploration pit" means an open pit dug to permit examination of the soil to evaluate its suitability for absorption systems. This is also referred to as a "test pit".
"Soil log" means a detailed description of soil characteristics and properties.
"Soil structure" means the way in which the individual particles, sand, silt, and clay, are arranged into larger distinct aggregates called peds. The main types of soil structure are granular, platy, blocky, prismatic, and columnar. Soil may not have a visible structure because it is either single grain or massive.
"Soil texture" means the percent of sand, silt, and clay in a soil mixture. Field methods for judging the texture of a soil are found in Section R317-4-14 Appendix C.
"Standard trench" means an absorption trench utilizing drain media into which effluent is discharged through specially designed distribution pipes.
"Suitable soil" means undisturbed soil that through textural and structural analysis or percolation rate meets the requirements for placement of an absorption system.
"Test pit" see "soil exploration pit".
"Unapproved system" means any onsite wastewater system that is deemed by the regulatory authority to be any:
A. installation without the required regulatory oversight, permits, or inspections;
B. repairs to an existing system without the required regulatory oversight, permits, or inspections; or
C. alteration to an existing system without the required regulatory oversight, permits, or inspections.
"USDA system of classification" means the system of classifying soil texture used by the United States Department of Agriculture.
"Waste" means dredged spoil, solid waste, incinerator residue, sewage, garbage, sewage sludge, munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and industrial, municipal, and agricultural waste discharged into water as defined in Section 19-5-102.
"Wastewater" means sewage, industrial waste or other liquid substances that might cause pollution of waters of the state. Intercepted ground water that is uncontaminated by wastes is not included.
"Wastewater holding tank" means a watertight receptacle designed to receive and store wastewater to facilitate treatment at another location.
"Waters of the state":
A. means all streams, lakes, ponds, marshes, watercourses, waterways, wells, springs, irrigation systems, drainage systems, and all other bodies or accumulations of water, surface and underground, natural or artificial, public or private, that are contained within, flow through, or border upon this state or any portion of the state; and
B. does not include bodies of water confined to and retained within the limits of private property, and that do not develop into or constitute a nuisance, or public health hazard, or a menace to fish or wildlife.
"Wind-blown sand" means sand that is formed by the weathering and erosion of sandstone typically found in sand-dune or sand-sheet deposits and is capable of producing sand and dust storms when disturbed.
. . . . . . .
R317-4-6. Design Requirements.
6.1. System Location.
A. Onsite wastewater systems are not suitable in some areas and situations. Location and installation of each system shall be such that with reasonable maintenance, it will function in a sanitary manner and will not create a nuisance, public health hazard, or endanger the quality of any waters of the state.
B. In determining a suitable location for the system, due consideration shall be given to such factors as:
1. the minimum setbacks in Section R317-4-13 Table 2;
2. size and shape of the lot;
3. slope of natural and final grade;
4. location of existing and future water supplies;
5. depth of ground water and bedrock;
6. soil characteristics and depth;
7. potential flooding or storm catchment;
8. possible expansion of the system; and
9. future connection to a public sewer system.
6.2. Minimum Setback Distances.
All systems, including the replacement area, shall conform to the minimum setback distances in Section R317-4-13 Table 2.
6.3. Maximum Ground Slope.
All absorption systems, including the replacement area, shall conform to the ground slope requirements in Section R317-4-4.
6.4 Estimates of Wastewater Quantity.
A. Single Family Dwellings.
A minimum of 300 gallons per day, 1 or 2 bedroom, and 150 gallons per day for each additional bedroom shall be used.
B. Non-Residential Facilities.
The quantity of wastewater shall be determined accurately, preferably by actual measurement. Metered water supply figures for similar installations can usually be relied upon, providing the non-disposable consumption, if any, is subtracted. Where this data is not available, the minimum design flow figures in Section R317-4-13 Table 3 shall be used to make estimates of flow.
C. Design Capacity.
In no event shall the anticipated maximum daily wastewater flow exceed the capacity for which a system is designed.
6.5. Non-Domestic Effluent.
Effluent shall be treated to levels at or below the defined parameters of non-domestic effluent before being discharged into an absorption system.
6.6. Building Sewer.
A. The building sewer shall have a minimum inside diameter of 4 inches and shall comply with the minimum standards in Section R317-4-13 Table 4.
1. If the sewer leaving the house is three inches, the building sewer may be three inches.
B. Building sewers shall be laid on a uniform minimum slope of not less than 1/4 inch per foot or 2.08% slope.
C. The building sewer shall have a minimum of one cleanout and cleanouts every 100 feet.
1. A cleanout is also required for each aggregate horizontal change in direction exceeding 135 degrees.
2. Ninety degree ells are not recommended.
D. Building sewers shall be separated from water service pipes in separate trenches, and by at least 10 feet horizontally, except that they may be placed in the same trench when all of the following conditions are met.
1. The bottom of the water service pipe, at all points, shall be at least 18 inches above the top of the building sewer.
2. The water service pipe shall be placed on a solid shelf excavated at one side of the common trench with a minimum clear horizontal distance of at least 18 inches from the sewer or drain line.
3. The number of joints in the water service pipe should be kept to a minimum, and the materials and joints of both the sewer and water service pipes shall be of strength and durability to prevent leakage under adverse conditions.
4. If the water service pipe crosses the building sewer, it shall be at least 18 inches above the latter within 10 feet of the crossing. Joints in water service pipes should be located at least 10 feet from such crossings.
E. Building sewer placed under driveways or other areas subjected to heavy loads shall receive special design considerations to ensure against crushing or disruption of alignment.
6.7. Septic Tank.
All septic tanks shall meet the requirements of Section R317-4-14 Appendix A and be approved by the division. Septic tanks shall be constructed of sound, durable, watertight materials that are not subject to excessive corrosion, frost damage, or decay. They shall be designed to be watertight, and to withstand all expected physical forces.
A. Liquid capacity.
1. A septic tank that serves a non-residential facility shall have a liquid capacity of at least 1-1/2 times the designed daily wastewater flow. In all cases the capacity shall be at least 1,000 gallons.
2. The capacity of a septic tank that serves a single family dwelling shall be based on the number of bedrooms that can be anticipated in the dwelling served, including the unfinished space available for conversion as additional bedrooms. Unfinished basements shall be counted as a minimum of one additional bedroom.
a. The minimum liquid capacity of the tank shall be 1,000 gallons for up to three bedroom homes.
b. The minimum liquid capacity of the tank shall be 1,250 gallons for four bedroom homes.
c. Two hundred fifty gallons per bedroom shall be added to the liquid capacity of the tank for each additional bedroom over four bedrooms.
3. The regulatory authority may require a larger capacity than specified in this subsection as needed for unique or unusual circumstances.
B. Tanks in Series.
1. No tank in the series shall be smaller than 1,000 gallons.
2. The capacity of the first tank shall be at least two-thirds of the required total septic tank volume. If compartmented tanks are used, the compartment of the first tank shall have this two-thirds capacity.
3. The connecting pipes between each successive tank shall meet the slope requirements of the building sewer and shall be unrestricted except for the inlet to the first tank and the outlet for the last tank.
C. Maximum Number of Tanks or Compartments.
The maximum number of tanks and compartments in series may not exceed three.
D. Inlets and Outlets.
Inlet or outlet devices shall conform to the following:
1. Approved tanks with offset inlets may be used where they are warranted by constraints on septic tank location.
2. Multiple outlets from septic tanks shall be prohibited unless preauthorized by the regulatory authority.
3. A gas deflector may be added at the outlet of the tank to prevent solids from entering the outlet pipe of the tank.
E. Effluent Screens.
All septic tanks may have an effluent screen installed at the outlet of the terminal tank. The screen shall prevent the passage of solid particles larger than a nominal 1/8 inch diameter sphere. The screen shall be easily removable for routine servicing by installing a riser to the ground surface, with an approved cover. Effluent screens are required for non-domestic wastewater systems, unless screening is achieved by some other means acceptable to the regulatory authority.
F. Access to Tank Interior.
Adequate access to the tank shall be provided to facilitate inspection, pumping, servicing, and maintenance, and shall have no structure or other obstruction placed over it and shall conform to all of the following requirements.
1. Riser Heights.
Watertight risers are required, extending to within 6 inches of the surface of the ground when soil covering the septic tank is greater than 6 inches. Preferably, the riser should be brought up to the final grade to encourage periodic servicing and maintenance.
a. If a septic tank is located under paving or concrete, risers shall be extended up through the paving or concrete.
b. If non-domestic wastewater is generated, risers shall be extended to the final grade.
2. Riser Diameter.
The inside diameter of the riser shall be a minimum of 20 inches.
3. Riser Covers.
Riser covers shall be designed and constructed in such a manner that:
a. they cannot pass through the access openings;
b. when closed will be child-proof;
c. will prevent entrance of surface water, dirt, or other foreign materials; and
d. seal odorous gases in the tank.
4. Riser Construction.
The risers shall be constructed of durable, structurally sound materials that are approved by the regulatory authority and designed to withstand expected physical loads and corrosive forces.
5. Multiple Risers Required.
When the tank capacity exceeds 3,000 gallons, a minimum of two access risers shall be installed.
G. Other Requirements.
Tank installation shall conform to all of the following requirements.
1. Ground Water.
a. Septic tanks located in high groundwater areas shall be designed with the appropriate weighted or anti-buoyancy device to prevent flotation in accordance with the manufacturer's recommendations.
b. The building sewer inlet of the tank may not be installed at an elevation lower than the highest anticipated groundwater elevation.
i. If the tank serves a mound or packed bed alternative system and has an electronic control panel capable of detecting water intrusion , the building sewer inlet of the tank may be installed below the maximum anticipated groundwater elevation.
(1) Any component below the anticipated maximum ground water elevation shall be water tightness tested.
2. Depth of Septic Tank.
The minimum depth of cover over the septic tank shall be at least 6 inches and a maximum of 48 inches at final grading. For unusual situations, the regulatory authority may allow deeper burial provided the following conditions are met.
a. The tank shall be approved by the division for the proposed depth and burial cover load.
b. Risers shall:
i. be installed over the access openings of the inlet and outlet baffles or sanitary tees; and
ii. conform to Subsection R317-4-6.7.F, except risers shall be at least 24 inches in diameter.
6.8. Grease Interceptor Tanks.
A grease interceptor tank or automatic grease removal device may be required by the regulatory authority to receive the drainage from fixtures and equipment with grease-laden waste. It shall be sized according to the current Plumbing Code.
A. Accessibility and Installation.
Tanks installed in the ground shall conform to Subsection R317-4-6.7.F for accessibility and installation, except risers are required and shall be brought to the surface of the ground. All interior compartments shall be accessible for inspecting, servicing, and pumping.
6.9. Pump and Recirculation Tanks.
A. Tanks shall be constructed of sound, durable, watertight materials that are not subject to excessive corrosion, frost damage, or decay. They shall be designed to be watertight, and to withstand all expected physical forces.
B. Pump tank volume shall have a liquid capacity adequate for the minimum operating volume that includes the dead space, dosing volume, and surge capacity, and shall have the emergency operation capacity of:
1. storage capacity for the system design daily wastewater flow;
2. at least two independent power sources with appropriate wiring installed; or
3. other design considerations approved by the regulatory authority that do not increase public health risks in the event of pump failure.
C. Accessibility and Installation.
Tanks shall conform to Subsection R317-4-6.7.F for accessibility and installation, except risers are required and shall be brought to the surface of the ground. All interior compartments shall be accessible for inspecting, servicing, and pumping.
D. Outlets of septic tanks upstream of pump tanks shall be fitted with an effluent screen, unless a pump vault is used in a pump tank.
6.10. Pump Vaults.
Pump vaults may be used when approved by the regulatory authority.
A. The vault shall be constructed of durable material and resistant to corrosion.
B. The vault shall have an easily accessible screen with 1/8 inch openings or smaller.
C. All components of the vault shall be accessible from the surface.
D. When a pump vault is used in a septic tank:
1. The tank size shall be increased by the larger of the following:
a. two hundred fifty gallons; or
b. ten percent of the required capacity of the tank.
2. At least two independent power sources with appropriate wiring, or other design considerations approved by the regulatory authority that do not increase public health risks, shall be installed.
3. The maximum drawdown within the tank shall be no more than 3 inches per dose.
6.11. Pumps.
See Section R317-4-14 Appendix B for details.
6.12. Sampling Ports.
When a system is required to have effluent sampling or receives non-domestic wastewater, the system shall include a sampling port at an area approved by the regulatory authority capable of sampling effluent prior to the absorption system.
6.13. Effluent Sewer.
A. The effluent sewer shall have a minimum inside diameter of 4 inches and shall comply with the minimum standards in Section R317-4-13 Table 4.
B. The effluent sewer shall extend at least 5 feet beyond the septic tank before entering the absorption system.
C. Effluent sewers shall be laid on a uniform minimum slope of not less than 1/4 inch per foot or 2.08% slope. When it is impractical, due to structural features or the arrangement of any building, to obtain a slope of 1/4 inch per foot, a sewer pipe of 4 inches in diameter or larger may have a slope of not less than 1/8 inch per foot or 1.04% slope when approved by the regulatory authority.
D. The effluent sewer lines shall have cleanouts at least every 100 feet.
E. Effluent sewer placed under driveways or other areas subjected to heavy loads shall receive special design considerations to ensure against crushing or disruption of alignment.
6.14. Absorption Systems.
A. System Types.
1. Absorption Trenches.
a. Standard Trenches.
b. Chambered Trenches.
c. Bundled Synthetic Aggregate Trenches.
2. Absorption Beds.
3. Deep Wall Trenches.
4. Seepage Pits.
B. General Requirements.
1. Replacement Area for Absorption Systems.
Adequate and suitable land shall be reserved and kept free of permanent structures, traffic, or adverse soil modification for 100% replacement of each absorption system. If approved by the regulatory authority, the area between standard trenches or deep wall trenches may be regarded as replacement area.
a. In lieu of a replacement area, two complete absorption systems shall be installed with a diversion valve. The valve shall be accessible from the final grade. The valve should be switched at least annually.
2. Protection of Absorption Systems.
The site of the initial and replacement absorption system may not be covered by asphalt, concrete, or structures, or be subject to vehicular traffic, or other activity that would adversely affect the soil, such as construction material storage, soils storage, etc. This protection applies before and after construction of the onsite wastewater system.
3. Sizing Criteria for Absorption Systems.
Absorption systems shall be sized based on Section R317-4-13 Table 5 or 6.
4. Design Criteria for Absorption Systems.
Many different designs may be used in laying out absorption systems, the choice depending on the size and shape of the available areas, the capacity required, and the topography of the dispersal area.
a. Horizontal Setbacks.
Absorption systems shall comply with the setbacks in Section R317-4-13 Table 2.
b. Sloping Ground.
Absorption systems placed in 10% or greater sloping ground shall be designed so that there is a minimum of 10 feet of undisturbed earth measured horizontally from the bottom of the distribution line to the ground surface. This requirement does not apply to drip irrigation.
c. Undisturbed Natural Earth.
That portion of absorption systems below the top of distribution pipes shall be in undisturbed natural earth.
d. Tolerance.
All piping, chambers, and the bottoms of absorption system excavations shall be designed level.
e. Distribution Pipe.
Distribution pipe for gravity-flow absorption systems shall be 4 inches in diameter and shall comply with the minimum standards in Section R317-4-13 Table 4.
i. The pipe shall be penetrated by at least two rows of round holes, each 1/2 inch in diameter, and located at approximately 6 inch intervals. The perforations should be located at about the five o'clock and seven o'clock positions on the pipe.
ii. The open ends of the pipes shall be capped.
f. Absorption System Laterals.
Absorption system laterals should be designed to receive proportional flows of wastewater.
g. Drain Media Protection.
Drain media shall be covered with a barrier material before being covered with earth backfill.
h. Prohibitions.
i. In gravity-flow absorption systems with multiple distribution lines, the effluent sewer may not be in direct line with any one of the distribution pipes, except where drop boxes or distribution boxes are used.
ii. Any section of distribution pipe laid with non-perforated pipe may not be considered in determining the required absorption area.
iii. Perforated distribution pipe may not be placed under driveways or other areas subjected to heavy loads.
i. Exceptions.
Deep wall trenches and filled seepage pits may be allowed beneath unpaved driveways on a case-by-case basis by the regulatory authority, if the top of the distribution pipe is at least 3 feet below the final ground surface.
C. Effluent Distribution Devices.
1. Distribution Boxes.
Distribution boxes may be used on level or nearly level ground. They shall be watertight and constructed of durable, corrosion resistant material. They shall be designed to accommodate the inlet pipe and the necessary distribution lines.
a. The outlet inverts of the distribution box shall be not less than 1 inch below the inlet invert.
b. Distribution boxes shall have risers brought to final grade.
2. Drop Boxes.
Drop boxes shall be watertight and constructed of durable, corrosion resistant material and may be used to distribute effluent within the absorption system and shall meet the following requirements:
a. Drop boxes shall be designed to accommodate the inlet pipe, an outlet pipe leading to the next drop box, except for the last drop box, and one or two distribution pipes leading to the absorption system.
b. The inlet pipe to the drop box shall be at least 1 inch higher than the outlet pipe leading to the next drop box.
c. The invert of the distribution pipes shall be 1 through 6 inches below the outlet invert. If there is more than one distribution pipe, their inverts shall be at exactly the same elevation.
d. Drop boxes shall have risers brought to final grade.
3. Effluent Pump to Absorption System.
a. If a pump is used to lift effluent to an absorption system, the pump tank or pump vault shall meet the requirements of Subsection R317-4-6.9 or R317-4-6.10 and the pump and controls shall meet the requirements of Section R317-4-14 Appendix B.
b. Pumping to an absorption system may not warrant any reductions to the absorption area.
4. Other Devices.
Tees, wyes, ells, or other distributing devices may be used as needed to permit proportional flow to the branches of the absorption system. A clean out or other means of access from the surface shall be provided for these devices.
D. Effluent Distribution Methods.
1. Closed Loop.
In locations where the slope of the ground over the absorption system area is relatively flat, the trenches should be interconnected to produce a closed loop system and the trenches shall be installed at the same elevations.
2. Non-Closed Loop.
If a non-closed loop design is used, effluent shall be proportionally distributed to each lateral.
3. Serial or Sequential.
Serial or sequential distribution may be used in absorption systems designed for sloping areas, or where absorption system elevations are not equal.
a. Serial trenches shall be connected with a drop box or watertight overflow line in such a manner that a trench will be filled before the effluent flows to the next lower trench.
b. The overflow line shall be a 4-inch solid pipe with direct connections to the distribution pipes. It should be laid in a trench excavated to the exact depth required. Care must be exercised to ensure a block of undisturbed earth remains between trenches. Backfill should be carefully tamped.
4. Pressure Distribution.
a. General Requirements.
i. Conformance to Applicable Requirements.
All requirements stated elsewhere in this rule for design, setbacks, construction and installation details, performance, repairs, and abandonment shall apply.
ii. Design Criteria.
All systems that use this method shall be designed by a person certified at Level 3 in accordance with Rule R317-11.
(1) The designer shall submit details of all system components with the necessary calculations.
(2) The designer shall provide to the local health department and to the owner operation and maintenance instructions that include the minimum inspection levels in Section R317-4-13 Table 7 for the system.
iii. Record in the Chain of Title.
When a system utilizing pressure distribution exists on a property, notice of the existence of that system shall be recorded in the chain of title for that property.
b. Design.
i. Pressure distribution may be permitted on any site meeting the requirements for an onsite wastewater system if conditions in this rule can be met.
ii. Pressure distribution should be considered when:
(1) effluent pumps are used;
(2) the flow from the dwelling or structure exceeds 3,000 gallons per day;
(3) soils are a Type 1 or have a percolation rate faster than five minutes per inch; or
(4) soils are a Type 5 or have a percolation rate slower than 60 minutes per inch.
iii. The Utah Guidance for Performance, Application, Design, Operation and Maintenance: Pressure Distribution Systems document shall be used for design requirements, along with the following:
(1) Dosing pumps, controls and alarms shall comply with Section R317-4-14 Appendix B.
(2) Pressure distribution piping.
(a) All pressure transport, manifold, lateral piping, and fittings shall meet PVC Schedule 40 standards or equivalent.
(b) The ends of lateral piping shall be constructed with sweep elbows or an equivalent method to bring the end of the pipe to final grade. The ends of the pipe shall be provided with threaded plugs, caps, or other devices acceptable to the regulatory authority to allow for access and flushing of the lateral.
E. Design of Absorption Systems.
i. An absorption system shall be designed to approximately follow the ground surface contours so that variation in excavation depth will be minimized. The excavations could be installed at different elevations, but the bottom of each individual excavation shall be level throughout its length.
ii. Absorption systems should be constructed as shallow as is possible to promote treatment and evapotranspiration.
iii. Observation ports may be placed to observe the infiltrative surfaces of the trenches or beds.
1. Absorption Trenches.
a. Absorption trenches shall conform to the following:
i. The minimum required effective absorption area shall be calculated using Section R317-4-13 Table 5 or 6.
ii. The effective absorption area of absorption trenches shall be calculated as the total bottom area of the excavated trench system in square feet.
iii. Minimum number of absorption trenches: 2.
iv. Maximum length of absorption trenches, not including connecting trenches: 150 feet.
v. Minimum spacing of absorption trenches from wall to wall: 7 feet.
vi. Minimum width of absorption trench excavations: 24 inches.
vii. Maximum width of absorption trench excavations: 36 inches.
viii. Minimum depth of absorption trench excavations below original, natural grade: 10 inches.
ix. Minimum depth of soil cover over the absorption trenches: 6 inches.
x. Minimum separation from the bottom of the absorption trenches to:
(1) the anticipated maximum ground water table: 24 inches; and
(2) unsuitable soil or bedrock formations: 48 inches.
b. Standard Trenches.
Standard trenches shall conform to the following:
i. Top of distribution pipe may not be installed above original, natural grade.
ii. The distribution pipe shall be centered in the absorption trench and placed the entire length of the trench.
iii. Drain media shall extend the full width and length of the trenches to a depth of at least: 12 inches.
iv. Minimum depth of drain media under the distribution pipe: 6 inches.
v. Minimum depth of drain media over the distribution pipe: 2 inches.
vi. Minimum depth of cover over the barrier material: 6 inches.
c. Chambered Trenches.
Chambered trenches shall conform to the following:
i. All chambers shall meet International Association of Plumbing and Mechanical Officials (IAPMO) Standard PS 63-2005, which is hereby incorporated into this rule by reference.
ii. The minimum required effective absorption area of chambered trenches shall be calculated:
(1) for Type A Chambers as: 36 inches; and
(2) for Type B Chambers as: 24 inches;
(3) using Section R317-4-13 Table 5 or 6 and may be reduced by: 30%.
iii. The chambered trenches shall be designed and installed in conformance with manufacturer recommendations, as modified by these rules.
iv. Type A Chambers.
(1) Minimum width of chambers: 30 inches.
(2) Maximum width of trench excavations: 36 inches.
v. Type B Chambers.
(1) Minimum width of chambers: 22 inches.
(2) Maximum width of trench excavations: 24 inches.
vi. Minimum elevation of the inlet pipe invert from the bottom of the chamber: 6 inches.
vii. All chambers shall have a splash plate under the inlet pipe or another design feature to avoid unnecessary channeling into the trench bottom.
viii. Inlet and outlet effluent sewer pipes shall enter and exit the chamber endplates.
ix. Minimum depth of cover over the chambers: 12 inches.
The depth of cover may be reduced to no less than 6 inches, if approved by the regulatory authority, considering the protection of absorption systems as required in Subsection R317-4-6.14.B.2, and other activities, as determined by the authority.
d. Bundled Synthetic Aggregate Trenches.
Bundled synthetic aggregate trenches shall conform to the following.
i. All synthetic aggregate bundles shall meet IAPMO Standards for the General, Testing and Marking and Identification of the guide criteria for Bundled Expanded Polystyrene Synthetic Aggregate Units.
ii. The effective absorption area of bundled synthetic aggregate trenches shall be calculated as the total bundle length times the total bundle width in square feet.
iii. The bundled synthetic aggregate trenches shall be designed and installed in conformance with manufacturer recommendations, as modified by these rules.
iv. Only 12-inch diameter bundles are approved in this rule.
(1) For bundles with perforated pipe the minimum depth of synthetic aggregate under pipe: 6 inches.
v. Width of trenches.
(1) When designed for a 3 foot wide trench, three bundles are laid parallel to each other with the middle bundle containing perforated pipe.
(2) When designed for a 2 foot wide trench, two bundles are placed on the bottom, with one bundle containing perforated pipe.
vi. Minimum depth of cover over the bundles: 12 inches.
The depth of cover may be reduced to no less than 6 inches, if approved by the regulatory authority, considering the protection of absorption systems as required in Subsection R317-4-6.14.B.2, and other activities, as determined by the authority.
2. Absorption Beds.
Absorption beds shall conform to the requirements applicable to absorption trenches, except for the following.
a. The minimum required effective absorption area shall be calculated using Section R317-4-13 Table 5 or 6.
b. The effective absorption area of absorption beds shall be considered as the total bottom area of the excavated bed system in square feet.
c. Absorption beds may be built over naturally existing soil types per Section R317-4-13 Table 5 or 6.
d. The bottom of the entire absorption bed shall be level.
e. The distribution pipes or chambers shall be interconnected to produce a closed loop distribution system.
f. Minimum number of laterals in an absorption bed: 2.
g. Maximum length of laterals in an absorption bed: 150 feet.
h. Maximum distance between laterals: 6 feet.
i. Minimum distance between laterals and sidewalls: 1 foot.
j. Maximum distance between laterals and sidewalls: 3 feet.
k. Minimum distance between absorption beds: 7 feet.
l. Minimum depth of an absorption bed excavation from original, natural grade: 10 inches.
m. Absorption beds with drain media:
i. Minimum depth of drain media under distribution pipe: 6 inches.
ii. Minimum depth of drain media over distribution pipe: 2 inches.
iii. Minimum depth of cover over the barrier material: 6 inches.
n. Absorption beds with chambers:
i. Chambers shall be installed with sides touching, no separation allowed.
ii. All chambers shall be connected in a closed loop distribution system.
iii. The outlet side of the chamber runs shall be connected through the bottom port of the end plates.
iv. No absorption area reduction factor shall be given for using chambers in absorption beds.
v. Minimum depth of cover over the chambers: 12 inches.
3. Deep Wall Trenches.
Deep wall trenches shall conform to the following:
a. The minimum required effective absorption area shall be calculated using Section R317-4-13 Table 5 or 6.
b. The effective absorption area of deep wall trenches shall be calculated using the total trench vertical sidewall area below the distribution pipe. The bottom area and any highly restrictive or impervious strata or bedrock formations may not be considered in determining the effective sidewall absorption area.
c. If percolation tests are used, they shall be conducted in accordance with Section R317-4-14 Appendix D and in the most restrictive soil horizon.
d. Maximum length of trenches: 150 feet.
i. Does not include connecting trenches.
e. Minimum spacing of trenches from wall to wall: 12 feet,
or three times the depth of the media under the distribution pipe, whichever is the larger distance.
f. Vertical depth of trenches.
i. Minimum effective sidewalls: 2 feet.
ii. Maximum effective sidewalls: 10 feet.
iii. Calculate using only suitable soil formation.
g. Minimum width of trench excavations: 24 inches.
h. Minimum separation from the bottom of deep wall trench to:
i. the anticipated maximum ground water table: 48 inches;
ii. unsuitable soil or bedrock formations: 48 inches.
i. Drain media shall cover the coarse drain media to permit leveling of the distribution pipe and shall extend the full width and length of the trenches.
i. Minimum depth of drain media: 12 inches.
ii. Minimum depth of drain media under the distribution pipe: 6 inches.
iii. Minimum depth of drain media over the distribution pipe: 2 inches.
j. Minimum depth of cover over the barrier material: 6 inches.
k. The distribution pipe shall be centered in the trench and placed the entire length of the trench.
l. Setback to property lines: 10 feet.
4. Seepage Pits.
Seepage pits shall be considered as modified deep wall trenches and shall conform to the requirements applicable to deep wall trenches, except for the following:
a. The effective absorption area of seepage pits shall be calculated using the total pit vertical sidewall area below the distribution pipe. The bottom area and any highly restrictive or impervious strata or bedrock formations may not be considered in determining the effective sidewall absorption area.
b. Minimum diameter of pits: 3 feet.
c. Vertical depth of pits.
i. Minimum effective sidewalls: 4 feet.
ii. Maximum effective sidewalls: 10 feet.
iii. Calculate using only suitable soil formation.
d. Filled Seepage Pits.
i. In pits filled with coarse drain media, the perforated distribution pipe shall run across each pit. A layer of drain media shall be used for leveling the distribution pipe.
ii. The entire pit shall be completely filled with coarse drain media to at least the top of any permeable soil formation to be calculated as effective sidewall absorption area.
e. Hollow-Lined Seepage Pits.
i. For hollow-lined pits, the inlet pipe shall extend horizontally at least 1 foot into the pit.
ii. The annular space between the lining and excavation wall shall be filled with crushed rock or gravel ranging from 3/4 through 6 inches in diameter and free of fines, sand, clay or organic material. The maximum fines in the gravel shall be 2% by weight passing through a US Standard #10 mesh or 2.0 millimeter sieve.
iii. Minimum width of annular space between lining and sidewall: 12 inches.
iv. Minimum thickness of reinforced perforated concrete liner: 2-1/2 inches.
v. Minimum thickness of reinforced concrete top: 6 inches.
vi. Minimum depth of drain media in pit bottom: 6 inches.
vii. Minimum depth of cover over seepage pit top: 6 inches.
viii. A reinforced concrete top shall be provided.
(1) When the cover over the seepage pit top exceeds 6 inches, risers shall conform to Subsection R317-4-6.7.F for accessibility.
6.15. Alternative Systems.
A. System Types.
1. At-Grade.
2. Mounds.
3. Packed Bed Media.
a. Intermittent Sand Filters.
b. Recirculating Sand Filters.
c. Recirculating Gravel Filters.
d. Textile Filters.
e. Peat Filters.
4. Sand Lined Trenches.
B. General Requirements.
1. Conformance to Applicable Requirements.
All requirements stated elsewhere in this rule for design, setbacks, construction and installation details, performance, repairs and abandonment shall apply unless stated differently for a given alternative system.
2. Sizing Criteria for Alternative Systems.
Absorption area shall be sized based on Section R317-4-13 Table 5 or 6 except as specified in this section.
3. Design Criteria for Alternative Systems.
All alternative systems shall be designed by a person certified at Level 3 in accordance with Rule R317-11.
a. The designer shall submit details of all system components with the necessary calculations.
b. The designer shall provide to the local health department and to the owner operation and maintenance instructions that include the minimum inspection levels in Section R317-4-13 Table 7 for the system.
4. Record in the Chain of Title.
When an alternative system exists on a property, notice of the existence of that system shall be recorded in the chain of title for that property.
C. Design of Alternative Systems.
1. At-Grade Systems.
Absorption trenches and absorption beds may be used in at-grade systems. At-grade systems shall conform to the requirements applicable to absorption trenches and absorption beds, except for the following:
a. Horizontal setbacks in Section
R317-4-13 Table 2 are measured from edge of
trench sidewall[ trench], [with the exception of]except at property lines, where the toe of the final cover
shall be 5 feet or greater in separation distance to a property
line.
b. Minimum number of observations ports provided within absorption area: 2.
i. The ports shall be installed to the depth of the trench or bed.
c. Depth of absorption excavations below natural grade: 0-10 inches.
d. Minimum cover over the absorption area: 6 inches.
e. Maximum slope of natural ground surface: 4%.
f. The maximum side slope for above ground fill shall be four horizontal to one vertical: 25% slope.
g. Where final contours are above the natural ground surface, the cover shall extend from the center of the wastewater system at the same general top elevation for a minimum of 10 feet in all directions beyond the limits of the absorption area perimeter, before beginning the side slope.
2. Mound Systems.
Mound systems shall conform to the following:
a. The design shall generally be based on the Wisconsin Mound Soil Absorption System: Siting, Design and Construction Manual, January 2000 published by the University of Wisconsin-Madison Small-Scale Waste Management Project, with the following exceptions.
i. The minimum separation distance between the natural ground surface and the anticipated maximum ground water table: 12 inches.
ii. Mound systems may be built over naturally existing soil types per Section R317-4-13 Table 5 or 6 provided the minimum depth of suitable soil is:
(1) between the natural ground surface and bedrock formations or unsuitable soils: 36 inches; or
(2) above soils that have a percolation rate faster than one minute per inch: 24 inches.
iii. The minimum depth of sand media over natural soil: 12 inches.
iv. The maximum slope of natural ground surface: 25 %.
v. The separation distances in Section R317-4-13 Table 2 are measured from the toe of the final cover.
vi. The effluent loading rate at the sand media to natural soil interface shall be calculated using Section R317-4-13 Table 5 or 6.
vii. The effluent entering a mound system shall be at levels at or below the defined parameters of non-domestic effluent.
viii. The minimum thickness of aggregate media around the distribution pipes of the absorption system shall be the sum of 6 inches below the distribution pipe, the diameter of the distribution pipe and 2 inches above the distribution pipe or 10 inches, whichever is larger.
ix. The cover may not be less than 6 inches in thickness, and shall provide protection against erosion, frost, storm water infiltration and support vegetative growth and aeration of distribution cell.
x. A minimum of three observation ports shall be located within the mound at each end and the center of the distribution cell.
(1) At least one port shall be installed at the gravel-sand interface, and one port at the sand-soil interface.
b. Mounds shall use pressure distribution.
i. The Utah Guidance for Performance, Application, Design, Operation and Maintenance: Pressure Distribution Systems document and Subsection R317-4-6.14.D.4 shall be used for design requirements.
(1) See Section R317-4-14 Appendix B for pump and control requirements.
3. Packed Bed Media Systems.
Packed bed media systems shall conform to the following:
a. System Design Criteria.
i. Wastewater Design Flows.
(1) For single-family dwellings the design shall be based on a minimum of 300 gallons per day for two bedrooms and 100 gallons per day for each additional bedroom.
(2) All other flow estimates shall be based on Subsection R317-4-6.4.
(3) Special design considerations shall be given for non-domestic effluent.
ii. Effluent Distribution.
Effluent shall be uniformly distributed over the filter media using pressure distribution.
b. Absorption System Requirements.
Absorption systems shall conform to the following:
i. Siting Conditions.
Packed bed media absorption systems may be sited under the following conditions:
(1) The minimum separation distance between the natural ground surface and the anticipated maximum ground water table: 12 inches.
(2) Packed bed media absorption systems may be built over naturally existing soil types per Section R317-4-13 Table 5 or 6 provided the minimum depth of suitable soils:
(a) above soils that have a percolation rate faster than one minute per inch: 24 inches; and
(b) between the natural ground surface and bedrock formations or unsuitable soils: 36 inches; or
(c) between the natural ground surface and bedrock formations or unsuitable soils: 18 inches based on an evaluation of infiltration rate and hydrogeology from a professional geologist or engineer that is certified at the appropriate level to perform onsite wastewater system design and having sufficient experience in geotechnical engineering based on:
(i) type, extent of fractures, presence of bedding planes, angle of dip;
(ii) hydrogeology of surrounding area; and
(iii) cumulative effect of all existing and future systems within the area for any localized mounding or surfacing that may create a public health hazard or nuisance, description of methods used to determine infiltration rate and evaluations of surfacing or mounding conditions.
(3) A non-chemical disinfection unit, capable of meeting laboratory testing parameters in Table 7.3, and a maintenance schedule consistent to Section R317-4-13 Tables 7.1 and 7.3, shall be used in excessively permeable soils.
(4) Conformance with the minimum setback distances in Section R317-4-13 Table 2, except for the following that require a minimum of 50 feet of separation:
(a) watercourses, lakes, ponds, reservoirs;
(b) non-culinary springs or wells;
(c) foundation drains, curtain drains; or
(d) non-public culinary grouted wells, constructed as required by Title R309.
ii. Sizing Criteria.
The minimum required effective absorption area shall be calculated using Section R317-4-13 Table 5 or 6 and may be reduced by: 30%.
(1) The use of chambered trenches with a packed bed media system may not receive additional reductions as allowed in Subsection R317-4-6.14.E.1.c.
iii. Separation from Ground Water Table.
The bottom of the absorption system shall have a vertical separation distance of at least 12 inches from the anticipated maximum ground water table.
iv. Observation Ports.
A minimum of two observation ports shall be provided within the absorption area.
v. Drip Irrigation.
Drip irrigation absorption may be used for packed bed media absorption system effluent dispersal based on type of soil and drip irrigation manufacturer's recommendations.
(1) Materials shall be specifically designed and manufactured for onsite wastewater applications.
(2) Non-absorption components shall be installed per Section R317-4-6 and Section R317-4-13 Table 2.
c. Intermittent Sand Filter Systems.
i. Media.
Either sand media or sand fill as described below may be used.
(1) Minimum depth of sand media: 24 inches.
(2) Minimum depth of sand fill: 24 inches.
(a) Effective size: 0.35-0.5 millimeter.
(b) Uniformity coefficient: less than 4.0.
(c) Maximum fines passing through #200 sieve: 1%.
ii. Maximum application rate per day per square foot of media surface area:
(1) Sand media: 1.0 gallons.
(2) Sand fill: 1.2 gallons.
iii. Maximum dose volume through any given orifice for each dosing: 2 gallons.
iv. Effluent entering an intermittent sand filter shall be at levels at or below the defined parameters of non-domestic effluent.
c. Recirculating Sand Filter (RSF) Systems.
i. Media.
(1) Minimum depth of washed sand: 24 inches.
(2) Effective size: 1.5-2.5 millimeter.
(3) Uniformity coefficient: less than 3.0.
(4) Maximum fines passing through #50 sieve: 1%.
ii. Maximum application rate per day per square foot of media surface area: 5 gallons.
d. Recirculating Gravel Filter (RGF) Systems.
i. Media.
(1) Minimum depth of washed gravel: 36 inches.
(2) Effective size: 2.5-5.0 millimeter.
(3) Uniformity Coefficient: less than 2.0.
(4) Maximum fines passing through #16 sieve: 1%.
ii. Maximum application rate per day per square foot of media surface area: 15 gallons.
e. Textile Filter Systems.
i. Media shall be geotextile, AdvanTex, or an approved equal.
ii. Maximum application rate per day per square foot of media surface area: 30 gallons.
f. Peat Filter Systems.
i. Minimum depth of peat media: 24 inches.
ii. Maximum application rate per day per square foot of media surface area: 5 gallons.
4. Sand Lined Trench Systems.
Sand lined trench systems shall conform to the following:
a. Siting Conditions.
i. The minimum depth of suitable soil or saprolite between the sand media in trenches and the anticipated maximum ground water table: 12 inches.
ii. Sand lined trench systems may be built over naturally existing:
(1) soil types 1 through 4; or
(2) soils or saprolite with a percolation rate between 1 and 60 minutes per inch.
iii. The minimum depth of suitable soil or saprolite is:
(1) between the sand media in trenches and bedrock formations or unsuitable soils: 36 inches; or
(2) above soils or saprolite that have a percolation rate faster than one minute per inch: 24 inches.
c. Trench Requirements.
Sand lined trenches shall conform to the requirements applicable to absorption trenches except for the following:
i. Trenches in Suitable Soil.
The minimum required effective absorption area shall be calculated using Section R317-4-13 Table 5 or 6.
ii. Trenches in Saprolite.
The minimum required effective absorption area shall be based on percolation rate using Section R317-4-13 Table 5.
(1) This rate shall be determined by conducting percolation tests. The soil shall be allowed to swell not less than 24 hours or more than 30 hours.
iii. The use of chambered trenches with a sand media system may not receive additional reductions as allowed in Subsection R317-4-6.14.E.1.c.
iv. Width of absorption trench excavations: 36 inches.
v. The entire trench sidewall shall be installed in natural ground. At-Grade system designs are not allowed.
vi. Minimum depth of sand media: 24 inches.
vii. Sand lined trenches with drain media.
(1) Minimum depth of drain media under the pressure lateral distribution pipe: 6 inches.
(2) Minimum depth of drain media over pressure lateral distribution pipe: 2 inches.
(3) Minimum depth of soil cover or saprolite over drain media: 6 inches.
viii. Sand lined trenches with Type A chambers.
(1) Minimum depth of soil cover or saprolite over chambers: 12 inches.
ix. Minimum number of observation ports per trench: 1.
c. Effluent Distribution.
Effluent shall be uniformly distributed over the sand media using pressure distribution.
i. Design shall generally be based on the Utah Guidance for Performance, Application, Design, Operation and Maintenance: Pressure Distribution Systems document.
. . . . . . .
R317-4-13. Tables.
. . . . . . .
TABLE 2
Minimum Separation Distances in Feet (a)
Item Requiring From Building From Septic, From
Setback Sewers and Pump, and Absorption
Effluent Other Area and
Sewers Tanks Replacement
Area
Absorption and 5 (b)
Replacement Areas
Public Culinary (c) 100 (c) 100 (c)
Water Sources
Individual or 25 50 100 (e)
Non-public
Culinary Water
Sources (d)
Culinary Water (f) 10 (f) 10 (f)
Supply Line
Non-culinary Well 10 25 100
or Spring
Lake, Pond, 10 25 100
Reservoir (a)
Watercourse (live or 25 100 (g)
ephemeral stream,
river, subsurface
drain, canal, storm water
drainage systems,
etc.)
Building Foundation
Without foundation 5 5 (h)
drain
With foundation 10 100 (i)
drain
Curtain drains 10 10 100 (i)
Dry washes, gulches, 25 50
and gullies
Swimming pool, 3 10 25
below ground
Dry wells, catch 5 25
basins
Down slopes that 10 50 (j)
exceed 35%. This
includes all
natural slopes or
escarpments and any
manmade cuts,
retaining walls,
or embankments.
Property line 5 5 5
NOTES
(a) All distances are from edge to edge. Where surface
waters are involved, the distance shall be measured from
the high water line.
(b) See Subsection R317-4-6.14 for setback requirements.
(c) All distances shall be consistent with Rule s R309-600
and R309-605.
(d) Compliance with separation requirements does not
guarantee acceptable water quality in every instance.
Where geological or other conditions warrant, greater
distances may be required by the regulatory authority.
(e) For ungrouted wells and springs the distance shall be
200 feet. A private or individual well is considered to
be grouted if it meets the construction standards
required in Section R655-4-11, which requires a minimum
30-foot deep grout surface seal. Private or individual
wells not constructed to this minimum standard are
considered to be ungrouted. Although this distance
shall be generally[] adhered to as the minimum required
separation distance,[] exceptions maybe approved by the
regulatory authority,[] taking into account geology,
hydrology, topography,[] existing land use agreements,
consideration of the[] drinking water source protection
requirements,[] protection of public health and potential
for[] pollution of water source. Any person proposing
to[] locate an absorption system closer than 200 feet
to[] an individual or nonpublic ungrouted well or
spring[] must submit a report to the regulatory authority
that considers the above items. In no case shall
the regulatory authority grant approval for an onsite
wastewater system to be closer than 100 feet from an
ungrouted well or a spring.
(f) If the water supply line is for a public water supply,
the separation distance shall comply with the requirements
of Rule R309-550. No culinary water service line shall
pass through any portion of an absorption area.
(g) Lining or enclosing watercourses with an acceptable
impervious material may permit a reduction in the
separation requirement. In situations where the bottom of
a canal or watercourse is at a higher elevation than the
ground in which the absorption system is to be installed,
a reduction in the distance requirement may be justified,
but each case shall be decided on its own merits by the
regulatory authority.
(h) Horizontal setback between a deep wall trench or
seepage pit and a foundation of any building is at least
20 feet.
(i) The regulatory authority may reduce the separation
distance, if it can be shown that the effluent will not
enter the drain, but each case must be decided on its own
merits by the regulatory authority. In no case shall the
regulatory authority grant approval for an absorption area
to be closer than 20 feet.
(j) This setback may be reduced if a 53 foot reference line
originating at the bottom of the distribution pipe, sloped
at 35% below horizontal, will not daylight or intersect
the ground surface.
. . . . . . .
TABLE 4
Minimum Standards for Building Sewer, Effluent Sewer, and Distribution Pipe Materials (a)
Acceptable Building Sewer and Effluent Sewer Materials
Type of Pipe Minimum Standard
Acrylonitrile-Butadiene Styrene ASTM (b) D-2680 (c), D-2751,
(ABS) [Schedule 40] F-628
Polyvinyl Chloride (PVC) ASTM D-2665, D-3033, D-3034
[Schedule 40]
Acceptable Distribution Pipe Materials
Type of Pipe Minimum Standard
ABS [Schedule 40] ASTM D-2661, D-2751
Polyethylene (PE), Smooth Wall ASTM D-3350
PVC [Schedule 40] ASTM D-2665, D-3033, D-3034 ,
[PVC] [ASTM] D-2729 (d)
NOTES
(a) Each length of building sewer, effluent sewer, and
distribution pipe shall be stamped or marked.
(b) American Society for Testing and Materials.
(c) For domestic wastewater only, free from industrial
wastes.
(d) Although perforated PVC, ASTM D-2729 is approved for
absorption system application, the solid-wall version of
this pipe is not approved for any application.
TABLE 5
M[in]aximum Hydraulic Loading Rates for Percolation Testing
Percolation Rate Absorption Systems Absorption Beds
(Minutes per Inch) Hydraulic Loading and Mound Systems
Rates (a) Hydraulic Loading
(gal/[day/]ft[2] 2 /day) Rates (b)
(c)(d)(e) (gal/[day/]ft[2] 2 /day)
(c)(d)(f)
0-10 (g) 0.90 0.45
11-20 0.70 0.35
21-30 0.60 0.3
31-40 0.55 0.27
41-50 0.50 0.25 (h)
51-60 0.45 0.22 (h)
61-90 (i) 0.40 (j)
91-120 (i) 0.35 (j)
NOTES
(a) The following formula may be used in place of the
values in this table: q = 2.35 divided by the square root
of the percolation rate and then add 0.15 where q is the
hydraulic loading rate. In no case shall the loading
rate be greater than 1.0[For percolation rates faster than].
1 minute per inch, 1 minute per inch shall be used in the
formula
(b) The following formula may be used in place of the
values in this table: q = 1.2 divided by the square root
of the percolation rate and then add 0.08 where q is the
hydraulic loading rate. In no case shall the loading
rate be greater than 0.5[For percolation rates faster than].
1 minute per inch, 1 minute per inch shall be used in the
formula
(c) Minimum absorption area is equal to the actual or
estimated wastewater flow in gallons per day shown in
Section R317-4-13 Table 3, divided by the hydraulic loading
rate within the applicable percolation rate category.
(d) For non-residential facilities, if a garbage grinder
is not used, the absorption area may be reduced by 10% (0.9
multiplier). If any automatic sequence washer is not used,
the absorption area may be reduced by 30% (0.7 multiplier).
If both of these appliances are not used, the absorption
area may be reduced by 40% (0.6 multiplier).
(e) For non-residential facilities, a minimum of 150 square
feet of trench bottom or sidewall absorption area shall be
provided.
(f) For non-residential facilities, a minimum of 300 square
feet of absorption area shall be provided.
(g) Soils with a percolation rate faster than 1 minute per
inch are only acceptable with the use of an alternative
packed bed media system with a disinfection unit.
(h) Not suitable for absorption beds.
(i) Acceptable for alternative packed bed media systems
only.
(j) Not suitable for absorption beds or mounds.
TABLE 6
M[in]aximum Hydraulic Loading Rates for Soil Classification
Texture Structure Absorption Systems Absorption Beds
Hydraulic Loading and Mound
Rate (gal/ft[2] 2 /day) Systems
(a)(b)(c) Hydraulic
Loading Rate
(gal/ft[2] 2 /day)
(a)(b)(d)
Coarse sand, Single 0.9 (e) 0.45 (e
sand, loamy grain
coarse sand,
loamy sand
Fine sand, Single 0.7 0.35
very fine grain
sand, loamy
fine sand,
loamy very
fine sand
Coarse sandy Massive 0.45 0.22 (f)
loam, sandy Platy 0.5 0.25 (f)
loam Prismatic, 0.65 0.32
blocky,
granular
Fine sandy Massive 0.4 (g)
loam, very Platy 0.35 (g)
fine sandy Prismatic, 0.5 0.25 (f)
loam blocky,
granular
Loam Massive 0.4 (g)
Platy (e) (g)
Prismatic, 0.5 0.25 (f)
blocky,
granular
Silt loam Massive (e) (g)
Platy (e) (g)
Prismatic, 0.45 0.22 (f)
blocky,
granular
Sandy clay Massive (e)(h) (g)
loam, clay Platy (i) (i)
loam, silty Prismatic,
clay loam blocky, 0.4 (e)(h) (g)
granular
Silt, silty Massive (i) (i)
clay, sandy Platy (i) (i)
clay, clay Prismatic, 0.35 (e)(h) (g)
blocky,
granular
NOTES
(a) Minimum absorption area is equal to the actual or
estimated wastewater flow in gallons per day, using Section
R317-4-13 Table 3, divided by the hydraulic loading rate
within the applicable soil texture and structure category.
(b) For non-residential facilities, if a garbage grinder is
not used, the absorption area may be reduced by 10% (0.9
multiplier). If any automatic sequence washer is not used,
the absorption area may be reduced by 30% (0.7
multiplier). If both of these appliances are not used,
the absorption area may be reduced by 40% (0.6
multiplier).
(c) For non-residential facilities, a minimum of 150 square
feet of trench bottom or sidewall absorption area shall be
provided.
(d) For non-residential facilities, a minimum of 300 square
feet of absorption area shall be provided.(e) These soils
are usually considered unsuitable for
absorption systems, but may be suitable, depending upon the
percentage and type of fines in coarse grained porous
soils, and the percentage of sand and structure in fine
grained soils. Percolation testing shall be used for
further evaluation.
(f) Not suitable for absorption beds.
(g) Not suitable for absorption beds or mounds.
(h) These soils may be permissible for packed bed media
absorption systems only.
(i) These soils are unsuitable for any absorption system.
. . . . . . .
R317-4-14. Appendices.
Appendix A. Septic Tank Construction.
1.1. Plans for Tanks Required.
Plans for all septic tanks and underground holding tanks shall be submitted to the division for approval. Such plans shall show all dimensions, capacities, reinforcing, maximum depth of soil cover, and such other pertinent data as may be required. All tanks shall conform to the design drawing and shall be constructed under strict, controlled supervision by the manufacturer.
A. Precast Reinforced Concrete Tanks.
1. The walls and base of precast tanks shall be securely bonded together and the walls shall be of monolithic or keyed construction.
2. The sidewalls and bottom of such tanks shall be at least 3 inches in thickness.
3. The top shall have a minimum thickness of 4 inches.
4. Such tanks shall have reinforcing of at least 6 inch x 6 inch No. 6, welded wire fabric, or equivalent. Exceptions to this reinforcing requirement may be considered by the division based on an evaluation of acceptable structural engineering data submitted by the manufacturer.
5. All concrete used in precast tanks shall be Class A, at least 4,000 pounds per square inch, and shall be vibrated or well-rodded to minimize honeycombing and to assure water tightness.
6. Precast sections shall be set evenly in a full bed of sealant. If grout is used it shall consist of two parts plaster sand to one part cement with sufficient water added to make the grout flow under its own weight.
7. Excessively mortared joints should be trimmed flush.
8. The inside and outside of each mortar joint shall be sealed with a waterproof bituminous sealing compound.
9. For the purpose of early reuse of forms, the concrete may be steam cured. Other curing by means of water spraying or a membrane curing compound may be used and shall comply to best acceptable methods as outlined in Guide to Curing Concrete, ACI308R-01, by American Concrete Institute, Farmington Hills, Michigan.
B. Poured-In-Place Concrete Septic Tanks.
1. The top of poured-in-place septic tanks with a liquid capacity of 1,000 to 1,250 gallons shall be a minimum of 4 inches thick, and reinforced with 3/8 inch reinforcing rods 12 inches on center both ways, or equivalent.
2. The top of tanks with a liquid capacity of greater than 1,250 gallons shall be a minimum of 6 inches thick, and reinforced with 3/8 inch reinforcing rods 8 inches on center both ways, or equivalent.
3. The walls and floor shall be a minimum of 6 inches thick. The walls shall be reinforced with 3/8 inch reinforcing rods 8 inches on center both ways, or equivalent. Inspections by the regulatory authority may be required of the tank reinforcing steel before any concrete is poured.
4. A 6 inch water stop shall be used at the wall-floor juncture to ensure water tightness.
5. All concrete used in poured-in-place tanks shall be Class A, at least 4,000 pounds per square inch, and shall be vibrated or well-rodded to minimize honeycombing and to ensure water tightness.
6. Curing of concrete shall comply with the requirements in Subsection R317-4-14 Appendix A.1.2.
C. Fiberglass Tanks.
1. Fiberglass tanks shall comply with one of the following criteria for acceptance.
a. The Interim Guide Criteria for Glass-Fiber-Reinforced Polyester Septic Tanks, International Association of Plumbing and Mechanical Officials Z1000-2007. The identifying seal of the International Association of Plumbing and Mechanical Officials shall be permanently embossed in the fiberglass as evidence of compliance.
b. Manufactured to meet the structural requirements of Underwriters Laboratories (UL) Standard 1316.
c. Professionally engineered plans demonstrating compliance to tank configuration requirements of this rule including acceptable structural calculations or other pertinent data as may be required.
2. Inlet and outlet tees shall be attached to the tank by a rubber or synthetic rubber ring seal and compression plate, or in some other manner approved by the division.
3. The tank shall be installed in accordance with the manufacturer's recommendations.
D. Polyethylene Tanks.
1. Polyethylene tanks shall comply with the criteria for acceptance established in Prefabricated Septic Tanks and Wastewater Holding Tanks, Can3-B66-10 by the Canadian Standards Association, Ontario, Canada.
2. Inlet and outlet tees shall be attached to the tank by a rubber or synthetic rubber ring seal and compression plate, or in some other manner approved by the division.
3. The tank shall be installed in accordance with the manufacturer's recommendations.
1.2. Identifying Marks.
A. All prefabricated or precast tanks that are commercially manufactured shall be plainly, legibly, and permanently marked or stamped with:
1. the manufacturer's name and address, or nationally registered trademark;
2. the liquid capacity of the tank in gallons on the exterior at the outlet end within 6 inches of the top of the wall; and
3. the inlet and outlet of all such tanks shall be plainly marked as "IN" or "OUT" respectively.
1.3. Inlets and Outlets.
Inlets and outlets of tanks or compartments thereof shall meet the minimum diameter requirements for building sewers.
A. Only one inlet or outlet is allowed, unless preauthorized by the regulatory authority.
B. Inlets and outlets shall be located on opposite ends of the tank.
1. The invert of flow line of the inlet shall be located at least 2 inches, above the invert of the outlet to allow for momentary rise in liquid level during discharge to the tank.
2. Approved tanks with offset inlets may be used when approved by the regulatory authority.
C. All inlets and outlets shall have a baffle or sanitary tee.
1. An inlet baffle or sanitary tee of wide sweep design shall be provided to divert the incoming wastewater downward. This baffle or tee is to penetrate at least 6 inches below the liquid level, but the penetration is not to be greater than that allowed for the outlet device.
2. For tanks with vertical sides, outlet baffles or sanitary tees shall extend below the liquid surface a distance equal to approximately 40% of the liquid depth. For horizontal cylindrical tanks and tanks of other shapes, that distance shall be reduced to approximately 35% of the liquid depth.
3. All baffles shall be constructed from sidewall to sidewall or shall be designed as a conduit.
4. All sanitary tees shall be permanently fastened in a vertical, rigid position.
D. Inlet and outlet pipe connections to the septic tank shall be sealed and adhere to the tank and pipes to form watertight connections with a bonding compound or sealing rings.
E. Inlet and outlet devices may not include any design features preventing free venting of gases generated in the tank or absorption system back through the roof vent in the building plumbing system. The top of the baffles or sanitary tees shall extend at least 6 inches above the liquid level in order to provide scum storage, but no closer than 1 inch to the inside top of the tank.
1.4. Liquid Depth of Tanks.
Liquid depth of tanks shall be at least 30 inches. Depth in excess of 72 inches may only be considered in calculating liquid volume required in Subsection R317-4-6.6 if the tank length is at least two times the liquid depth.
1.5. Burial Depth.
The maximum burial depth shall be stated on the plans submitted.
1.6. Tank Compartments.
Septic tanks may be divided into compartments provided they meet the following:
A. The volume of the first compartment shall equal or exceed two-thirds of the total required septic tank volume;
B. No compartment shall have an inside horizontal dimension less than 24 inches;
C. Inlets and outlets shall be designed as specified for tanks, except that when a partition wall is used to form a multi-compartment tank, an opening in the partition may serve for flow between compartments provided the minimum dimension of the opening is 4 inches, the cross-sectional area is not less than that of a 6 inch diameter pipe (28.3 square inches), and the mid-point is below the liquid surface a distance approximately equal to 40% of the liquid depth of the tank.
1.7. Scum Storage.
Scum storage volume shall consist of 15% or more of the required liquid capacity of the tank and shall be provided in the space between the liquid surface and the top of inlet and outlet devices.
1.8. Access to Tank Interior.
Adequate access to the tank shall be provided to facilitate inspection, servicing and maintenance, and shall have no structure or other obstruction placed over it and shall conform to the following requirements:
A. Access to each compartment of the tank shall be provided through properly placed manhole openings not less than 18 inches in diameter, in minimum horizontal dimension or by means of an easily removable lid section.
B. All access covers shall be designed and constructed in such a manner that they cannot pass through the access openings, and when closed will be child-proof and prevent entrance of surface water, dirt, or other foreign material, and seal the odorous gases in the tank. Concrete access covers for manhole openings shall have adequate handles.
C. Access to inlet and outlet devices shall be provided through properly spaced openings not less than 12 inches in minimum horizontal dimension or by means of an easily removable lid section.
Appendix B. Pressure Distribution, Pumps, Controls, and Alarms.
1.1. Design.
The design shall generally be based on the Utah Guidance for Performance, Application, Design, Operation and Maintenance: Pressure Distribution Systems document with the following exceptions:
A. Design and equipment shall emphasize ease of maintenance, longevity, and reliability of components and shall be proven suitable by operational experience, test, or analysis, acceptable to the regulatory authority.
B. Electrical disconnects shall be provided that are appropriate for the installation and shall have gas-tight junction boxes or splices. Electrical components used in onsite wastewater systems shall comply with applicable requirements of the State of Utah Electrical Code.
C. All components shall be constructed and installed to facilitate ease of service without having to alter any other part.
1.2. Pumps, Controls, and Alarms.
Prior to final approval for operation, all pumps, controls and related apparatus shall be field tested and found to operate as designed.
A. When duplex pump system is designed, controls shall be provided that an alarm will signal when one of the pumps malfunctions.
B. Where multiple pumps are operated in series, controls shall be installed to prevent the operation of a pump or pumps preceding a station that experiences a high level alarm event.
C. Controls shall be capable of controlling all functions incorporated or required in the design of the system.
1. The control panel for all pressure distribution systems shall include a pump run-time hour meter and a pump event counter or other acceptable flow measurement method.
2. The control panel shall be installed within sight of the access risers.
a. Other locations may be approved by the regulatory authority.
3. Supporting hydraulic calculations and pump curve analysis shall be submitted to the regulatory authority with the design.
Appendix C. Soil Exploration Pits, Soil Logs, Soil Evaluations.
1.1. Soil Exploration Pit Construction.
Soil conditions shall be obtained from soil exploration pit(s) dug to a depth of 10 feet in the absorption area, or to the ground water table if it is shallower than 10 feet below ground surface. In the event that absorption system excavations will be deeper than 6 feet, soil exploration pits shall extend to a depth of at least 4 feet below the bottom of the proposed absorption system excavation.
A. Soil exploration pits shall be constructed in a manner to reduce potential for physical injury. One end of each pit should be sloped gently or "stair-stepped" to permit easy entry if necessary.
1.2. Soil Logs.
A. The soil log shall contain the following information.
1. A signed statement certifying that the logs were evaluated and recorded in accordance with this rule.
2. The names of all qualified individuals per Rule R317-11 conducting the tests.
3. The location of the property.
4. The location of the soil exploration pit on the property.
5. The date of the log.
6. A description and depths of the soil horizons throughout the soil exploration pit to include:
a. soil texture and structure using the USDA system of classification;
b. estimated volume percentage of coarse fragments defined as:
i. "Gravel" means a rock fragment from 0.1 inches to 3 inches in diameter;
ii. "Cobble" means rock fragment from 3 inches to 10 inches in diameter;
iii. "Stone" means a rock fragment greater than 10 inches in diameter;
c. the presence and abundance of mottling defined as:
i. "Few" when less than 2% of the exposed surface is occupied by mottles;
ii. "Common" when from 2% to 20% of the exposed surface is occupied by mottles; and
iii. "Many" when more than 20% of the exposed surface is occupied by mottles;
d. depth to groundwater or bedrock, if encountered, and maximum anticipated groundwater table; and
e. other pertinent information.
1.3. Soil Evaluation.
Soils shall be evaluated using the USDA Soil Texture Classification method.
A. The soil horizon with the lowest loading rate shall be used in calculating the required absorption area.
Appendix D. Percolation Method.
1.1. Percolation Test Requirements.
Percolation tests shall be completed by an individual certified per Rule R317-11 and shall be conducted in accordance with the instructions in this appendix.
A. Typical Areas.
When percolation tests are conducted, such tests shall be conducted at points and elevations selected as typical of the area in which the absorption system will be located.
B. Percolation Test Certificate.
Percolation test results shall be submitted on a signed "Percolation Test Certificate". The test certificate shall contain the following:
1. A signed statement certifying that the tests were conducted in accordance with this rule.
2. The names of all individuals per Rule R317-11 conducting the tests.
3. The location of the property.
4. The location of the percolation tests on the property.
5. The depth to the bottom of the percolation test hole from the existing grade.
6. The final stabilized percolation rate of each test in minutes per inch.
7. The date of the tests.
8. Other pertinent information.
C. Specific Requirements.
Percolation tests shall be conducted at the owner's expense and in accordance with the following:
1. Conditions Prohibited for Test Holes.
Percolation tests may not be conducted in test holes that extend into ground water, bedrock, or frozen ground. Where shrink-swell clays, fissured soil formations, or saprolite is encountered, tests shall be made under the direction of the regulatory authority.
2. Soil Exploration Pit Prerequisite to Percolation Tests.
Since the appropriate percolation test depth depends on the soil conditions at a specific site, the percolation test shall be conducted only after the soil exploration pit has been dug and examined for suitable and porous strata and ground water table information. Percolation test results should be related to the soil conditions found.
3. Test Holes to Commence in Specially Prepared Excavations.
All percolation test holes should commence in specially prepared larger excavations, preferably made with a backhoe, of sufficient size that extend to a depth approximately 6 inches above the strata to be tested.
4. Type, Depth, and Dimensions of Test Holes.
Test holes shall be dug or bored, preferably with hand tools such as shovels or augers, etc., and shall have horizontal dimensions ranging from 4 to 18 inches, preferably 8 to 12 inches. The vertical sides shall be at least 12 inches deep, terminating in the soil at an elevation 6 inches below the bottom of the proposed onsite wastewater system. In testing individual soil strata for deep wall trenches and seepage pits, the percolation test hole shall be located entirely within the strata to be tested, if possible.
5. Preparation of Percolation Test Hole.
Carefully remove any smeared soil surfaces to provide an open, natural soil interface into that water may percolate. Remove all loose soil from the bottom of the hole. Add 2 to 3 inches of clean pea gravel to protect the bottom from scouring or sealing with sediment when water is added. Caving or sloughing in some test holes can be prevented by placing in the test hole a wire cylinder or perforated pipe surrounded by clean pea gravel.
6. Saturation and Swelling of the Soil.
It is important to distinguish between saturation and swelling. Saturation means that the void spaces between soil particles are full of water. This can be accomplished in a relatively short period of time. Swelling is a soil volume increase caused by intrusion of water into the individual soil particles. This is a slow process, especially in clay-type soil, and is the reason for requiring a prolonged swelling period.
7. Placing Water in Test Holes.
Water should be placed carefully into the test holes by means of a small diameter siphon hose or other suitable method to prevent washing down the side of the hole.
8. Percolation Rate Measurement, General.
Necessary equipment should consist of a tape measure with at least 1/16 inch calibration or float gauge, and a time piece or other suitable equipment. All measurements shall be made from a fixed reference point near the top of the test hole to the surface of the water.
9. Percolation Test Procedure.
The hole shall be carefully filled with clear water and a minimum depth of 12 inches shall be maintained above the gravel for at least a four hour period by refilling whenever necessary. Water remaining in the hole after four hours may not be removed. Immediately following the saturation period, the soil shall be allowed to swell not less than 16 hours or more than 30 hours. Immediately following the soil swelling period, the percolation rate measurements shall be made as follows:
a. Any soil that has sloughed into the hole shall be removed and water shall be adjusted to 6 inches over the gravel.
b. Thereupon, from the fixed reference
point, the water level shall be measured and recorded at
approximately 30 minute intervals for a period of four hours[, unless two successive water level drops do not vary more
than 1/16 of an inch and indicate that an approximate stabilized
rate has been obtained].
i. If 6 inches of water seeps away in less
than [15]30 minutes, a shorter time interval of
15 minutes between measurements may be used.
ii. If 6 inches of water seeps away in
less than [30]15 minutes, a shorter time interval of [1]5 minutes between measurements may be used.
iii. Eight consecutive time intervals shall be recorded unless two successive water level drops do not vary more than 1/16 of an inch and indicate that an approximate stabilized rate has been obtained.
c. The hole shall be filled with 6 inches of clear water above the gravel after each time interval.
d. In no case shall the water depth exceed 6 inches above the gravel.
e. The final water level drop shall be used to calculate the percolation rate.
i. If no stabilized rate is achieved, the smallest drop shall be used to make this calculation.
f. Precautions shall be taken to prohibit water or soil from freezing during the test procedure.
10. Test Procedure for Type 1 and Type 2 Soils.
The hole shall be carefully filled with clear water to a minimum depth of 12 inches over the gravel and the time for this amount of water to seep away shall be determined. The procedure shall be repeated and if the water from the second filling of the hole at least 12 inches above the gravel seeps away in 10 minutes or less, the test may proceed immediately as follows:
a. Water shall be added to a point not more than 6 inches above the gravel.
b. Thereupon, from the fixed reference point, water levels shall be measured at 10 minute intervals for a period of one hour.
i. If 6 inches of water seeps away in less than 10 minutes, a shorter time interval of 5 minutes between measurements may be used.
ii. Six consecutive time intervals shall be recorded unless two successive water level drops do not vary more than 1/16 of an inch and indicate that an approximate stabilized rate has been obtained.
c. The hole shall be filled with 6 inches of clear water above the gravel after each time interval.
d. In no case shall the water depth exceed 6 inches above the gravel.
e. The final water level drop shall be used to calculate the percolation rate.
i. If no stabilized rate is achieved, the smallest drop shall be used to make this calculation.
11. Calculation of Percolation Rate.
The percolation rate is equal to the time elapsed in minutes for the water column to drop, divided by the distance the water dropped in inches and fractions thereof.
12. Using Percolation Rate to Determine Absorption Area.
The minimum or slowest percolation rate shall be used in calculating the required absorption area.
Appendix E. Tank Operation and Maintenance.
1.1. Maintenance of Septic Tanks.
A. Septic tanks shall be emptied before too much sludge or scum is allowed to accumulate and seriously reduce the tank volume settling depth. If either the settled solids or floating scum layer accumulate too close to the bottom of the outlet baffle or bottom of the sanitary tee pipe in the tank, solid particles will overflow into the absorption system and eventually clog the soil and ruin its absorption capacity.
B. A septic tank that receives normal loading should be inspected as indicated in Section R317-4-11 to determine if it needs emptying. Although there are wide differences in the rate that sludge and scum accumulate in tanks, a septic tank for a private residence will generally require emptying every three to five years. Actual measurement of scum and sludge accumulation is the only sure way to determine when a tank needs to be emptied. Experience for a particular system may indicate the desirability of longer or shorter intervals between inspections.
C. The tank should be completely emptied if either the bottom of the floating scum mat is within 3 inches of the bottom of the outlet baffle or tee or the sludge level has built up to approximately 12 inches from the bottom of the outlet baffle or tee, or the scum and sludge layers together equal 40% or more of the tank volume. All scum and solids should be washed out and removed from the tank.
D. If multiple tanks or tanks with multiple compartments are provided, care should be taken to ensure that each tank or compartment is inspected and emptied.
E. Septic tank wastes contain disease causing organisms and shall be disposed of only in areas and in a manner that is acceptable to local health authorities and consistent with state rules.
F. Immediate replacement of damaged inlet or outlet fittings in the septic tank is essential for effective operation of the system.
G. Effluent screens or filters.
Remove the filter in a manner that prevents solids from passing to the absorption system. Wash the filter over the inlet side of septic tank. Replace the cleaned filter back into the outlet tee.
H. When the tank is empty, the interior surfaces of the tank should be inspected for leaks or cracks using a strong light.
I. A written record of all maintenance of the septic tank and absorption system should be kept by the owner of that system.
J. The functional operation of septic tanks is not improved by the addition of yeasts, disinfectants, additives or other chemicals; therefore, use of these materials is not recommended.
K. The advice of your regulatory authority should be sought before chemicals arising from a hobby or home industry or other unusual activities are discharged into a septic tank system.
L. Economy in the use of water helps prevent overloading of a septic tank system that could shorten its life and necessitate expensive repairs. The plumbing fixtures in the building should be checked regularly to repair any leaks that can add substantial amounts of water to the system. Industrial wastes and other liquids that may adversely affect the operation of the onsite wastewater system should not be discharged into such a system. Paper towels, facial tissue, disinfectant wipes, newspaper, wrapping paper, disposable diapers, sanitary napkins, coffee grounds, rags, sticks, and similar materials should also be excluded from the septic tank since they do not readily decompose and can lead to clogging of both the plumbing and the absorption system.
1.2. Maintenance of Other Tanks.
A. Other Tanks.
Any measurable amount of sludge or scum present in other tanks should be removed.
B. If a screen is present, it should be rinsed and cleaned over the opening of the septic tank.
KEY: waste water, onsite wastewater systems, alternative onsite wastewater systems, septic tanks
Date of Enactment or Last Substantive Amendment: [September 1, 2013]2015
Notice of Continuation: February 3, 2015
Authorizing, and Implemented or Interpreted Law: 19-5-104
Additional Information
More information about a Notice of Proposed Rule is available online.
The Portable Document Format (PDF) version of the Bulletin is the official version. The PDF version of this issue is available at https://rules.utah.gov/publicat/bull-pdf/2015/b20151101.pdf. The HTML edition of the Bulletin is a convenience copy. Any discrepancy between the PDF version and HTML version is resolved in favor of the PDF version.
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For questions regarding the content or application of this rule, please contact Judy Etherington at the above address, by phone at 801-536-4344, by FAX at 801-536-4301, or by Internet E-mail at jetherington@utah.gov. For questions about the rulemaking process, please contact the Division of Administrative Rules.