DAR File No. 37853

This rule was published in the August 1, 2013, issue (Vol. 2013, No. 15) of the Utah State Bulletin.

Environmental Quality, Water Quality

Rule R317-5

Large Underground Wastewater Disposal Systems

Notice of Proposed Rule


DAR File No.: 37853
Filed: 07/15/2013 04:51:15 PM


Purpose of the rule or reason for the change:

The proposed amendments update the rule to conform with changes to the Utah Water Quality Act initiated by S.B. 21 passed in the 2012 General Legislative Session.

Summary of the rule or change:

The proposed amendments update the rule to conform with changes to the Utah Water Quality Act initiated by S.B. 21 (2012). The majority of the proposed changes are editorial, largely consisting of replacing the term "Executive Secretary" with "Director". However, the amendments also make additional changes mandated by S.B. 21 (2012) which reflect the transfer of certain powers and duties from the Water Quality Board to the Director of the Division of Water Quality in the realm of permits, certifications, and other administrative authorizations.

State statutory or constitutional authorization for this rule:

  • Section 19-5-104

Anticipated cost or savings to:

the state budget:

Enactment of these changes likely will not result in direct, measurable costs to the state budget as this amendment only changes who has authority to make regulatory decisions regarding permits, certifications, and other administrative authorizations.

local governments:

Enactment of these changes likely will not result in direct, measurable costs for local governments as this amendment only changes who has authority to make regulatory decisions regarding permits, certifications, and other administrative authorizations.

small businesses:

Enactment of these changes likely will not result in direct, measurable costs to small businesses as this amendment only changes who has authority to make regulatory decisions regarding permits, certifications, and other administrative authorizations.

persons other than small businesses, businesses, or local governmental entities:

Enactment of these changes likely will not result in direct, measurable costs to other persons as this amendment only changes who has authority to make regulatory decisions regarding permits, certifications, and other administrative authorizations.

Compliance costs for affected persons:

Enactment of these changes likely will not result in direct, measurable compliance costs as this amendment only changes who has authority to make regulatory decisions regarding permits, certifications, and other administrative authorizations.

Comments by the department head on the fiscal impact the rule may have on businesses:

Enactment of these changes likely will not result in direct, measurable costs to businesses as this amendment only changes who has authority to make regulatory decisions regarding permits, certifications, and other administrative authorizations.

Amanda Smith, Executive Director

The full text of this rule may be inspected, during regular business hours, at the Division of Administrative Rules, or at:

Environmental Quality
Water QualityRoom DEQ, Third Floor
195 N 1950 W

Direct questions regarding this rule to:

  • Dave Wham at the above address, by phone at 801-536-4337, by FAX at 801-536-4301, or by Internet E-mail at dwham@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:


This rule may become effective on:


Authorized by:

Walter Baker, Director


R317. Environmental Quality, Water Quality.

R317-5. Large Underground Wastewater Disposal Systems.

R317-5-1. General.

1.1 SCOPE: These [regulations]rules shall apply to large underground disposal systems for domestic wastewater discharges which exceed 5,000 gallons per day (gpd) and all other domestic wastewater discharges not covered under the definition of an "Onsite wastewater disposal system" in R317-1-1.13. Usually these systems should not be designed for over 15,000 gpd. In general, it is not acceptable to dispose of industrial wastewater in an underground disposal system.

1.2 ENGINEERING REPORT: An engineering report shall be submitted which shall contain design criteria along with all other information necessary to clearly describe the proposed project and demonstrate project feasibility.

1.3 SUBMISSION OF PLANS FOR REVIEW: Plans for new large underground wastewater disposal systems or extensions of existing systems shall be submitted to the [Department]Director for review as required by R317-1. All designs shall be prepared and submitted under the supervision of a registered professional engineer licensed to practice in the State of Utah and certified pursuant to R317-11. A construction permit must be issued by the [Utah Water Quality Board]Director prior to construction of the wastewater disposal system or the building(s) to be served by the wastewater system. The system designer must, following construction of the system, certify in writing that the system was installed in accordance with the approved plans and specifications.

A. Local Health Department Requirements - it is the applicant's responsibility to ensure that the Large Underground Wastewater Disposal System (LUWDS) application to the Division is in compliance with local health department requirements reqarding the location, design, construction and maintenance of an LUWDS prior to the applicant submitting a request for a construction permit to the [Division of Water Quality (DWQ)]Director. Local Health Departments may petition the [Division]Director to require local review for compliance with local requirements prior to DWQ initiating its review. Where the petition has been approved by the [Executive Secretary]Director, the applicant is required to submit documentation that the local health department has approved the proposed LUWDS prior to issuance of a construction permit.

1.4 OPERATION AND MAINTENANCE: Operation and maintenance shall be provided by the owner to ensure the disposal system is functioning properly at all times. An operating permit will be required for all large underground wastewater disposal systems to monitor that proper operation and maintenance is occurring for the protection of the environment and public health. The operating permit shall be issued by the [Division of Water Quality]Director or, by delegated authority, by the local health department having jurisdiction, and shall be effective for a period not to exceed 5 years from the issuance date.

A. Operating Permit Required: The owner of a large underground wastewater disposal system shall provide a written notice of intent (NOI) to the Division of Water Quality and the local health department having jurisdiction of its intent to operate a large underground wastewater disposal facility. Those systems currently in operation must submit the NOI no later than January 1, 2010. New systems permitted under this rule must submit the NOI prior to final inspection. The notice of intent shall be specific for the operating permit and shall include the following information:

1. Facility name and address; owner name, address, and phone number.

2. List of Facility Components, e.g., septic tank, pump tank, gravel drainfield trench, gravelless chambers, pressure drainfield, etc.

3. Design flow (gallons per day) and number and type of connections.

4. Type of waste treated and disposed, i.e., residential, restaurant, other commercial establishment, etc.

5. Sketch plan of existing system showing major facility components.

B. Local Health Department Authority to Issue Operating Permits:

1. A local health department that currently has approval from the [Division of Water Quality]Director to administer an alternative systems program may obtain authority within its jurisdiction to administer operating permits for large underground wastewater disposal systems by submitting a written request to administer this program. The request must include an agreement to implement and enforce inspection, servicing, monitoring, and reporting requirements of this rule.

2. Local health departments that have been delegated authority to administer the operating permit program must submit an annual report on or before September 1 of the calendar year, to the Division of Water Quality containing:

(a) A list of LUWD systems under delegation.

(b) A summary listing the compliance status of each system, showing those systems that are currently failing, and those systems that have been repaired.

(c) A summary of any enforcement actions taken, identifying those actions that are still pending, and those that been resolved.

C. Annual Report. The owner shall summit an annual covering the period of July 1 to June 30 (the "reporting year") to the permitting agency no later than August 1 of each year. In this report, the owner shall report the following items:

1. All information required to be submitted in the NOI.

2. Checklist of inspections performed including the date of the inspection and a list of findings.

3. Packed Bed media system sampling results.

4. Signature of owner or certified operator, and date.

D. Owner Responsibility to Maintain System: The owner is responsible for maintaining its large underground wastewater disposal system and for performing periodic inspections and servicing of its system. Inspections of conventional systems (gravity, or pump to gravity) shall be not less than once each reporting year, and inspections of at-grade, pressure, mound and packed bed media systems shall be not less than twice each reporting year. At a minimum, the owner is responsible for inspecting these components of the various type of system:

1. Community septic tank or treatment unit - measure sludge and scum levels, and pump when necessary.

2. Effluent filter - clean when necessary.

3. Inspect distribution box.

4. Inspect pump, floats, alarm and control panel, and record flow or hour meter reading.

5. Disposal field - inspect for ponding or surfacing in disposal area. Flush, clean, re-adjust to equal pressure in laterals.

E. Operation and Maintenance Manual Required: New systems must have a written operation and maintenance document describing the treatment and disposal system and outlining routine maintenance procedures, including checklists and maintenance logs needed for proper operation of the system. This document must be available at the time of the final inspection on all new systems.

F. Packed Bed Media System Sampling and Monitoring Requirements:

The owner of a packed bed media system is responsible for sampling and monitoring for COD (Chemical Oxygen Demand), TSS (Total Suspended Solids) and TIN (Total Inorganic Nitrogen) at an interval not exceeding six calendar months. Additional sampling and monitoring may be required if it has been determined that there is a potential for groundwater impacts. Effluent quality of a grab sample, before discharge to a disposal method, shall not exceed 75 mg/L COD or 25 mg/L TSS.

1. Effluent COD exceeding 75 mg/L or TSS exceeding 25 mg/L shall be followed up with weekly sampling commencing within 30 days until such time as two successive results are obtained that are within these limits. Any two successive samples resulting in exceedence of either 75 mg/L COD or 25 mg/L TSS shall result in the system being deemed non-compliant requiring further evaluation and a corrective action plan.

2. For non-complying systems, the permitting agency shall require the order:

(a) all necessary steps such as maintenance servicing, repairs, and/or replacement of system components to correct the system;

(b) effluent quality testing for COD and TSS shall continue every week until two successive samples of COD and TSS are found to be in compliance;

(c) payment of fees for additional inspections, reviews and testing;

(d) evaluation of the system design including non-approved changes to the system, the wastewater flow, and biological and chemical loading to the system;

(e) investigation of household practices related to the discharge of chemicals into the system, such as photo-finishing chemicals, laboratory chemicals, excessive amount of cleaners or detergents, etc.; and

(f) additional tests or samples to troubleshoot the system malfunction.


The drainage system of any building or establishment covered herein shall receive all wastewater as required by R309-100, the Utah Plumbing Code and shall have a connection to a public sewer except when such sewer is not available for use, in which case connection shall be made as follows:

A. To an underground wastewater disposal system found to be adequate and constructed in accordance with requirements stated herein.

B. To any other type of disposal system acceptable under R317-3.

1.6 MULTIPLE UNITS UNDER SEPARATE OWNERSHIP: Multiple Units Under Separate Ownership shall not be served by a common large underground disposal system except when, based upon sound engineering judgment, other alternatives are determined infeasible. In such cases, a common subsurface system may be used provided the following requirements are met:

A. The common subsurface disposal system and conveyance sewers shall be under the sponsorship of a body politic.

B. The subsurface absorption system shall be designed and constructed to provide duplicate capacity (two independent systems). Each system shall be designed to accommodate the total anticipated maximum daily flow. The duplicate systems shall be designed with appropriate valving, etc., to allow for periodic alternation of the use of each system.

C. Sufficient land area with suitable characteristics shall be available to provide for a third absorption system capable of handling the total maximum daily wastewater flow. This area shall be kept free of permanent structures, traffic or soil modification (See Section R317-5-3.1(L)).

D. The subsurface absorption system should be used only until a more permanent system becomes available.

1.7 NEW PROCESSES AND METHODS OF DISPOSAL: Where unusual conditions exist, other methods of disposal not described herein may be employed if approved by the [Utah Water Pollution Control Committee] Director and by the local health authority having jurisdiction. The approval will be based on evidence of adequacy to meet water quality standards and other requirements of the Code.

1.8 UNITS REQUIRED IN A LARGE UNDERGROUND WASTEWATER DISPOSAL SYSTEM: The large underground wastewater disposal system shall typically consist of the following:

A. A building sewer with cleanout.

B. A septic tank.

C. An effluent filter.

D. A pressurized subsurface disposal system. This may be an absorption field, deep wall trenches, absorption beds, or, for packed bed media applications, drip irrigation dispersal, depending on location, topography, soil conditions and maximum ground water level.

E. Accessibility components to insure proper maintenance and servicing. These may include risers on tanks to the surface of the ground, with firmly secured lids; and absorption field inspection ports.

F. Pressurized systems typically require a dosing chamber or dosing tank and cleanouts at the end of pressurized laterals.

G. Additional components may also be required depending on the waste stream characteristics and the need to provide adequate protection to groundwater. These components may include pretreatment devices such as grease traps, or may involve secondary treatment using packed bed media systems.

1.9 LOCATION AND INSTALLATION: Location and installation of the wastewater disposal system shall be such that with reasonable maintenance it will function properly and will not create a nuisance, health hazard or endanger the quality of any waters of the State. Due consideration shall be given to the size and shape of the area in which the system is installed, slope of natural and finished grade, soil characteristics, maximum ground water elevation, proximity of existing or future water supplies or water courses, possible flooding and expansion potential of the disposal system.

1.10 ISOLATION: The system shall be isolated as shown in Table 5-1.


(Undisturbed Earth)

                   Building Septic Absorption Seepage Absorption
                   Sewer    Tank   Field      Pit or  Bed
                                   Trench     trench

Drinking Water
Supply Source
  Deep Well        (a)100   100    100        100     100
  Shallow Well
    or Spring        (b)    (b)    (b)        (b)     (b)
  Domestic Water
    Supply Lines     (c)     10     10         10      10

Ponds, Lakes,
Reservoirs and
Water Courses        ---     25    (d)         (d)    (d)

Foundation Walls      3       5     25         25      25

Land Drain
  Located upslope    ---     10     20         20      20
    downslope        ---     25    100        100     100

Property Line         5       5      5         15      10

Seepage Pits
(Trenches)           ---      5     10         12(e)   10

Absorption beds      ---      5     10         10      10

Absorption fields    ---      5     (f)        10      10

     (a)  Sewers may be constructed within the 100 foot
protective zone, provided the sewer construction meets the
requirements of R309-106-2.3.4.
     (b)  It is recommended that the listed concentrated
sources of pollution be located at least 1,500 feet from
shallow wells and springs.  Any proposal to locate closer than
1,500 feet will be reviewed on a case-by-casebasis, taking
account geology, topography, existing land use agreements,
designated use of water system (public or non-public) and
potential for pollution of water sources.  It is the
responsibility of the water supply owner to establish an
adequate protection zone in accordance with the applicable
drinking water [regulations]rules.  Even separation of 1500
feet or greater from concentrated sources of pollution will not
guarantee suitability of the water supply system.
     (c)  The requirements stated in R317-5-1.13(F) must be met
     (d)  A minimum of 100 feet is desirable, but may be
modified to a lesser or greater distance, depending on soil
conditions or mitigating measures such as lining the water
course with impervious material.
     (e)  Seepage pits or seepage trenches must be installed
within an established absorption zone.  The absorption zone
will be sized based on the ratio of ground surface area "GSA"
to the required sidewall area "SWA".  The GSA/SWA ratio must
be at least 2.5.  The trenches and pits shall be installed
within the absorption zone such that the spacing between
trenches will be equal.  Spacing of 12 feet (sidewall to
sidewall) shall be a minimum.  Distance to the edge or
boundary of the established absorption zone shall be a minimum
of 15 feet.  The system must also conform to all other
separation requirements identified in Table 5-1.
     The required sidewall area "SWA" shall be computed based
on the design application rate with the associated soil type
depicted in Table 5-8.  The ground surface
area identified
within the absorption zone will be a minimum of 2.5 times the
required sidewall area.  An example of a typical seepage
trench design with variation is available from the
[Bureau of Water Pollution Control]Division.
     (f)  See Table 5-4.


1.11 CONSTRUCTION INSPECTION: Approval to operate the constructed/installed facilities shall be issued following a final inspection by a representative of the Department of Health. The facilities must be inspected after installation but prior to backfilling.

1.12 CONSTRUCTION MATERIALS: Materials used in construction of the system shall be durable, sound, and not unduly subject to corrosion. Pipe, pipe fittings and similar materials shall comply with the requirements of R309-100.

1.13 WASTEWATER DRAINAGE LINE OR BUILDING SEWER: Wastewater drainage lines (or building sewers) shall comply with R309-100, the Utah Plumbing Code, or meet the following requirements, whichever is more restrictive.

A. Any generally accepted material will be given consideration, but material selected shall be suitable for local conditions to include soil characteristics, external loadings, abrasions and similar problems.

B. The lines shall have a minimum inside diameter of 4 inches, in which case they shall be laid on a minimum slope of 1.25 percent. For sewer lines serving more than one dwelling unit, it is recommended that the line be sized greater than 4 inches in diameter. Lines of greater sizes should be designed for a minimum velocity of 2 feet per second based on the pipe flowing full. See R317-3 for calculation of flow velocities.

C. The lines shall have cleanouts every 50 feet and at all changes in direction or grade, except where manholes are installed every 400 feet and at every change in direction or grade.

D. On 4-inch and 6-inch lines, two 45 degree bends with cleanout will be acceptable in lieu of a manhole, and 90 degree ells are not recommended.

E. The design of wastewater pump stations shall comply with the requirements contained in R317-3.

F. Lines shall be separated from water service pipes in separate trenches and by at least 10 feet horizontally. If the local conditions prevent a 10 foot separation, or when sewer lines must cross water lines, the two lines may be placed within the 10 feet of each other, provided:

1. The bottom of the water service pipe, at all points, shall be at least 18 inches above the top of the wastewater drainage line at its highest point.

2. The water service pipe shall be placed in a separate trench or the line should be placed on a shelf of undisturbed soil to one side of the sewer line trench.

3. The number of joints in the service pipe shall be kept to a minimum and the materials and joints of both the sewer line and water service line shall be of a strength and durability to prevent leakage under known adverse conditions. The joints between the two lines shall be staggered to the extent possible.

4. When it is impossible to obtain the proper horizontal and vertical separation as stipulated above, both the water and sewer line shall be constructed in accordance with the requirements of R309-112.2.


. . . . . . .


R317-5-3. Absorption Systems.


A. Suitable soil exploration, to a depth of about 10 feet, or at least 4 feet below the bottom of the proposed absorption systems and percolation tests, shall be made to provide information on subsoil conditions. Percolation tests and soil exploration reports shall be completed and submitted as part of the engineering report for the disposal facility. After January 1, 2002, the soil evaluation and percolation tests must be done in accordance with certification requirements in R317-11. A minimum of 5 percolation tests must be conducted at different sites for each disposal system. Additional tests may be required, where necessary to adequately evaluate the total absorption system or where there is significant variability in test results. In general, the system will be sized based on the slowest stabilized percolation test rate. Soil logs should be prepared in accordance with the Unified Soil Classification System by a qualified individual. Requirements outlined in R317-5-4.1 and Table 5-8 will be helpful in developing this information.

B. Absorption devices, including seepage pits or trenches, placed in sloping ground should be so constructed that the horizontal distance between the distribution line and the ground surface is at least 10 feet.

C. Soil having excessively high permeability, such as gravel with large voids, affords little filtering and is unsuitable for absorption systems. Percolation rates (R317-5-4.1) of approximately 5 minutes per inch or less usually will not be acceptable.

The extremely fine-grained "blow sand" found in some parts of Utah is generally unsuitable for absorption systems and should be avoided. If no choice is available, systems may be constructed in such material, provided it is within the required percolation range specified in this code, and the required area is calculated on the minimum percolation rate (60 minutes per inch for absorption fields and 30 minutes per inch for absorption beds).

D. Absorption system excavations may be made by machinery provided that the soil in the bottom and sides of the excavation is not compacted. Strict attention shall be given to the protection of the natural absorption properties of the soil. Absorption systems shall not be excavated when the soil is wet enough to smear or compact easily. All smeared or compacted surfaces should be raked to a depth of one inch, and loose material removed before the filter material is placed in the absorption system excavation.

E. Effluent distribution lines or pipe shall be perforated and should consist of 4-inch diameter pipe of appropriate material which has demonstrated satisfactory results for the given application. The distribution pipe shall be bedded true to line and grade, uniformly and continuously supported on firm, stable material.

F. The coarse material in the absorption system shall consist of crushed stone, gravel, or similar material of equivalent strength and durability. It shall be free from fines, dust, sand or clay. The top of the stone or gravel shall be covered with a pervious material such as an acceptable synthetic filter fabric, a 2-inch compacted layer of straw, or similar material before being covered with earth backfill to prevent infiltration of backfill into the stone or gravel.

G. Distribution pipes placed under driveways or other areas subjected to heavy loads shall receive special design considerations to insure against crushing or disruption of alignment. Absorption area under driveways or pavement shall not be considered in determining the minimum required absorption area.

H. Absorption systems shall be backfilled with earth that is free from debris and large rocks. The first 4 to 6 inches of soil backfill should be hand placed. Distribution pipes shall not be crushed or misaligned during backfilling. When backfilling, the earth should be mounded slightly above the surface of the ground to allow for settlement.

I. Heavy equipment shall not be driven in or over absorption systems during backfilling or after completion.

J. That portion of absorption system below the top of distribution pipes shall be in natural soil. Under unusual circumstances the [Utah Water Pollution Control Committee]Director may allow installation in acceptably stabilized earth fill. The earth fill and location will have to be evaluated on a case-by-case basis, taking into consideration the soil characteristics and degree of consolidation of the fill material.

K. Soil and Ground Water Requirements. In areas where absorption systems are to be constructed, soil cover must be adequate to insure at least 4 feet of soil between bedrock or any other impervious formation, and the bottom of absorption systems. Maximum ground water elevation must be at least 2 feet below the bottom of absorption systems and at least 4 feet below finished grade.

L. Replacement Area for Absorption System. Adequate and suitable land shall be reserved and kept free of permanent structures, traffic, or adverse soil modification for replacement of the absorption system. Suitability must be demonstrated through soil exploration and percolation tests results.

3.2 ABSORPTION FIELDS: Absorption fields are the preferred type of absorption system. They consist of a series of gravel-filled trenches provided with perforated pipes designed to distribute septic tank effluent into the gravel fill, from which it percolates through the trench walls and bottom into the surrounding sub-surface soil.

A. Design of absorption fields shall be as outlined in Tables 5-3 and 5-4.


. . . . . . .


B. The minimum absorption area (total bottom area of trenches) of the absorption field shall be determined from the following equation but in no case the maximum allowable application rate shall exceed 2.2 gallons per square foot per day

Q = 5 / square root of t

Where Q = maximum rate of effluent application to the soil in gallons per square foot per day

t = stabilized percolation rate in minutes per inch

Percolation tests shall be performed as specified in R317-5-4.1. Rates in excess of 60 minutes per inch indicate a soil unsuitable for absorption field construction.

C. Wherever possible all trench bottoms should be constructed at the same elevation. Distribution pipes and trenches should be level and should be connected at both ends to provide a continuous system. If ground surface slope is too steep to permit a level installation, then a system of serial trenches following land contours should be used, with each trench and distribution pipe being constructed level but at a different elevation. A schematic diagram showing the recommended layout of trenches and distribution systems is available from the [Bureau of Water Pollution Control]Director.

1. The system should include drop boxes which should generally conform to the detail in Appendix 1 and should operate in such a manner that a trench will be filled with wastewater to the depth of the gravel fill before the wastewater flows to the next lower trench. The drop boxes shall be watertight and should be provided with a means of access at the top.

2. The lines between the drop boxes should be a minimum of 4 inches in diameter and should be watertight with direct connections to the distribution box. They should be laid in a trench excavated through undisturbed earth to the exact depth required. Backfill should be carefully tamped.


. . . . . . .


KEY: water pollution, sewerage

Date of Enactment or Last Substantive Amendment: [April 7, 2009]2013

Notice of Continuation: June 18, 2012

Authorizing, and Implemented or Interpreted Law: 19-5


Additional Information

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For questions regarding the content or application of this rule, please contact Dave Wham at the above address, by phone at 801-536-4337, by FAX at 801-536-4301, or by Internet E-mail at dwham@utah.gov.