DAR File No. 38271
This rule was published in the February 15, 2014, issue (Vol. 2014, No. 4) of the Utah State Bulletin.
Environmental Quality, Water Quality
Rule R317-5
Large Underground Wastewater Disposal (LUWD) Systems
Notice of Proposed Rule
(Repeal and Reenact)
DAR File No.: 38271
Filed: 01/31/2014 12:06:01 PM
RULE ANALYSIS
Purpose of the rule or reason for the change:
The purpose of this filing is to repeal the existing Rule R317-5 by replacing old language and awkward organization with newer concepts and technologies, referencing Rule R317-4 in similar subsections and parallel rules.
Summary of the rule or change:
Some highlights of the new rule include: 1) the new draft is not a "stand-alone" rule. It incorporates specific provisions in the new Rule R317-4 that are also pertinent to Large Underground Wastewater Disposal (LUWD) systems. These include: a) definitions; b) material standards; c) horizontal setbacks shown in Table 2 in Rule R317-4; d) soil exploration pits and percolation tests; e) design requirements; f) construction and installation; and g) final inspection; 2) outline and contents of new draft closely resemble Rule R317-4; 3) the addition of new authority and purpose sections to comply with format of other rules; 4) the scope section details where an engineer needs to consider factors in design such as flow, waste strength, site characteristics, etc.; 5) emphasis on sound engineering concepts needed for designing these large wastewater systems in more sensitive areas of the state with shallow groundwater or poorer soils being mindful of the increased design flows (over 5,000 pgd); 6) the entire rule has waiver capability granted by the director as long as the proposal does not override "the safeguarding of public health, protection of water quality, or engineering practice"; 7) twelve new definitions with LUWD systems language are included; 8) the new section titled General Standards, Prohibition, Requirements and Enforcement closely resembles Rule R317-4; 9) the new section Feasibility Determination and Concept Approval closely resembles the part of Rule R317-4 that are also pertinent to LUWD systems. In the old rule, no direction was given for applications for approval in concept. All new applications will have to obtain a feasibility determination prior to applying for a construction permit. This will include: a) number of soil logs and percolation tests required (it was unclear in the old rule); b) ground water determination (nothing previously specified; c) ground slope detailed up to 35%, using the same language as Rule R317-4; 10) Engineering Reports, Plans and Construction Permits includes more details about contents of reports and plans that are needed for DWQ review: a) must be designed by a Utah PE and certified Level 3 Onsite Professional per R317-11; details in applications closely resemble Rule R317-4; 11) the Design Requirements section references incorporation of Rule R317-4, with two minor exceptions, and details components required for a LUWD system (same as existing Rule R317-5). Horizontal separation distance between bottom of absorption trenches and anticipated highest ground water table is increased to 48 inches, unless pre-treatment unit is installed, then the separation can be 24 inches; 12) construction and installation is a new section that incorporates Rule R317-4 as a reference; 13) final Inspection and Authorization to Use inspection section references Rule R317-4 and the requirements are more clearly explained when compared to the old version; 14) operation and maintenance section has been overhauled. Closely resembles Rule R317-4 using the same frequency and inspection components; and 15) the section of the Operating Permits and Annual Inspection Reports has been removed which details what information is required to submit in order to obtain an operating permit on existing systems. This is no longer necessary as all LUWD systems have been identified and have operating permits. The rest of this section has the same language as the existing rule, explaining operating permits for new systems and annual inspection reports. Details on the inspection report with new fields to record septic tank measurements, pressure squirt height, date of last pumping, etc., which were all previously required on an operating permit.
State statutory or constitutional authorization for this rule:
- Title 19, Chapter 5
Anticipated cost or savings to:
the state budget:
No impact to state budget is anticipated. Design of large underground wastewater systems are made by the private sector representing the engineering community and their clients.
local governments:
This rule offers the Local Health Departments (LHDs) some aspects of administration of these systems, but it is strictly voluntary. Those LHDs not wanting to participate, which represent a majority of the counties in Utah, will still have the Division of Water Quality being the lead in review and administration. For those few counties asking for this authority, local ordinances with application fees should cover any of their costs.
small businesses:
As additional lots are developed, businesses involved in the design and construction of large underground wastewater disposal systems may show an increased need for their services and products.
persons other than small businesses, businesses, or local governmental entities:
This rule should not add any additional costs from the present rule. There is language that allows an engineer to seek a waiver from any section of this rule, provided sound engineering and equivalent environmental and public health protection is met.
Compliance costs for affected persons:
No difference in compliance costs is anticipated for affected persons since the overall requirements are nearly identical to the original rule, but have been better organized for easier reference.
Comments by the department head on the fiscal impact the rule may have on businesses:
There is no difference in the fiscal impact expected on businesses since most of the proposed changes are in rule organization and clarity.
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 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:
03/17/2014
This rule may become effective on:
03/24/2014
Authorized by:
Walter Baker, Director
RULE TEXT
R317. Environmental Quality, Water Quality.
[R317-5. Large Underground Wastewater Disposal Systems.
R317-5-1. General.
1.1 SCOPE: These 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 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 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 Director. Local Health
Departments may petition the Director to require local review for
compliance with local requirements prior to DWQ initiating its
review. Where the petition has been approved by the 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 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 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.
1.5 LARGE UNDERGROUND WASTEWATER DISPOSAL SYSTEM
REQUIRED:
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 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.
TABLE 5-1
MINIMUM HORIZONTAL SEPARATION IN FEET (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 Located 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 Footnotes: (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 into 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 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 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.
1.14 ESTIMATES OF WASTEWATER QUANTITY: The maximum daily
wastewater flow to be disposed of should be determined as
accurately as possible, preferably by actual measurement. Where
this is not possible, Table 5-2 may be used to estimate the
flow.
TABLE 5-2
ESTIMATED QUANTITY OF DOMESTIC WASTEWATER
TYPE OF ESTABLISHMENT GALLONS PER DAY Construction/work camps (semi-permanent) 60 per person Resort camps with limited plumbing 60 per person Country Clubs 25 per person Dwellings a. Boarding house 60 per person Additional kitchen waste for non-resident boarder 10 per person b. Boarding schools 75-100 per person c. Condominium 400 per unit d. Mobile home 400 per unit e. Single family dwelling 400 per day f. Rooming House 40 per person Highway Rest Areas (improved with restroom facilities) 5 per vehicle Hospitals 250 per bed Nursing Homes 200 per Bed Institutions other than Hospitals and Nursing Homes 75-125 per person Motels and Hotels 62 per person Industrial Buildings (exclusive of industrial waste) 15-35 per person Launderette (self-service) 50 per load Office Buildings a. With cafeteria 25 per employee b. Without cafeteria 15 per employee Recreational Vehicle Parks/ Campgrounds a. Sanitary stations for self-contained Vehicles 50 per space b. Independent spaces (temporary or transient with sewer connections) 125 per space c. Dependent spaces (temporary or transient with no sewer connections) 125 per space with service building including showers 35 per person (Campground) (1) with service building but no showers 85 per space 25 per person (Campground) d. Campground with no flush toilets 5 per person Restaurants 35 per seat a. Additional for bars and cocktail lounges 2 per person Schools a. Boarding 75 per person b. Day, without cafeteria, gymnasiums or showers 15 per person c. Day, with cafeteria, but no gymnasium or shower 20 per person d. Day, with cafeteria, gymnasium and shower 25 per person Service Station (per vehicle served) 5 per vehicle Ski Areas and Visitor Centers 5 per visitor
R317-5-2. Septic Tanks.
2.1 GENERAL REQUIREMENTS: Septic tanks shall be
constructed of durable materials designed to withstand expected
physical loads and corrosive forces. They shall be watertight and
designed to provide settling of solids, accumulation of sludge
and scum, and access for cleaning, as specified in the following
paragraphs.
2.2 TANK CAPACITY: Septic tanks shall be sized on the
following basis:
(1) V = 1.5Q for Q less than or equal to 1500
(2) V = 1125 + 0.75 Q for Q greater than 1500
V = liquid volume of tank in gallons
Q = (Maximum anticipated) wastewater discharge in gallons
per day
2.3 TANK DIMENSIONS: In general, tank length should be at
least 2 or 3 times the width. Liquid depth of tanks shall be at
least 30 inches. A liquid depth greater than 6 feet shall not be
considered in determining tank capacity.
2.4 TANK COMPARTMENTS: Septic tanks may be divided into
compartments, or separate tanks may be installed in series, up to
a maximum of 3, provided the following requirements are
met:
A. The volume of the first compartment or tank must equal
or exceed the volume of any other compartment.
B. No compartment or tank shall have an inside horizontal
dimension less than 24 inches.
C. Inlets and outlets shall be designed as specified for
tanks, except when a partition wall is used to form a
multi-compartment tank. Under such conditions, an opening in the
partition may be used to allow for flow between compartments,
provided the minimum dimension of the opening is 4 inches, the
cross-sectional area is not less than 30 square inches, and the
mid-point is below the liquid surface a distance approximately
equal to 40% of the liquid depth of the tank.
2.5 INLETS AND OUTLETS:
A. Inlets and outlets of tanks or compartments shall be
submerged or baffled to divert incoming flow toward the tank
bottom and minimize the discharge of sludge or scum in the
effluent.
B. Sanitary Tees may be used in lieu of baffled inlet or
outlet structures.
C. All outlet baffles shall extend below the liquid
surface a distance equal to approximately 40% of the liquid
depth. Space between the baffle top and the underside of the tank
cover shall be at least 1 inch.
D. 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 liquid surface and top of inlet devices, which
shall be set at least 1 inch below the underside of the tank
cover.
E. Inlets and outlets shall allow free venting of tank
gases back through the drainage system.
F. The inlet invert shall be at least 1 inch above outlet
invert.
2.6 ACCESS TO TANK:
A. Access to inlet and outlet devices shall be provided
through properly placed openings not less than 18 inches in
minimum horizontal dimension.
B. The top of the tank shall be at least 6 inches below
finished grade.
C. If the top of the tank is located more than 18 inches
below finished grade, all access openings required by sub-section
(1) above, shall be extended to within 18 inches of the finished
grade.
2.7 ABANDONED SEPTIC TANKS: Septic tanks, cesspools and
seepage pits which are no longer in use shall be completely
pumped and filled with sand or soil.
2.8 DISCHARGE TO ABSORPTION SYSTEM: Septic tank effluent
shall be conducted to the absorption system through a watertight
sewer line meeting the requirements for wastewater drainage lines
as contained in R317-5-1.13(A), (B), and (F). Tees, wyes, or
other distributing devices may be used as needed. If a
distribution box is used, it shall be of sufficient size to
accommodate the necessary distribution line connections. Outlet
inverts shall be at the same elevation and at least 1 inch below
the inlet invert. Conveyance to the absorption system must be
adequately sized to handle peak hydraulic flow.
R317-5-3. Absorption Systems.
3.1 GENERAL REQUIREMENTS:
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 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.
TABLE 5-3
ABSORPTION FIELD CONSTRUCTION DETAILS
ITEMS UNITS MINIMUM MAXIMUM Number of lateral trenches 2 - Length of trenches Feet - 100 Width of trenches Inches 12 36 Slope of pipe (bottom) In./100 ft. Level Level Depth of coarse material: Under pipe Inches 6 - Under pipe located within 10 ft. of trees Inches 12 - Over pipe Inches 2 - Size of coarse material Inches 3/4 2-1/2 Depth of backfill over coarse material Inches 6 -
TABLE 5-4
SIZE AND MINIMUM SPACING FOR ABSORPTION FIELD TRENCHES
Minimum Spacing of wall to Trenches Width of wall (ft.) trench at bottom (inches) 12 to 18 6.0 18 to 24 6.5 24 to 30 7.0 30 to 36 7.5
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
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.
3.3 ABSORPTION BEDS: Absorption beds consist of large
excavated areas provided with gravel fill in which effluent
distribution lines are laid. They may be used in place of
absorption fields when trenches are not considered desirable, and
shall conform to requirements applying to absorption fields,
except for the following:
A. They shall comply with construction details specified
in Table 5-5.
TABLE 5-5
ABSORPTION BED CONSTRUCTION DETAILS
ITEM UNIT MINIMUM MAXIMUM Distance between distribution lines Feet - 6 Distance between distribution lines and wall Feet - 3 Depth to bottom of bed Feet 1-1/2 - Size of coarse material Inches 3/4 2-1/2 Depth of coarse material Under pipe Inches 6 - In bed within 10 ft. of trees Inches 12 - Over pipe Inches 2 - Depth of backfill over coarse material Inches 6 -
B. Required absorption area (total bottom area of bed)
shall be determined from the following equation, but in no case
shall it exceed 1.1 gallons per square foot per day.
Q = 2.5/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 30 minutes per inch indicate a
soil unsuitable for absorption bed construction.
3.3 SEEPAGE PITS: If absorption fields or beds are not
feasible, seepage pits will be considered. These consist of deep
pits which receive septic tank effluent and allow it to seep
through sidewalls into the adjacent subsurface soil. Seepage pits
may be either hollow lined or filled with clean coarse material.
They shall conform to the following requirements:
A. Number and size of seepage pits required shall be
determined by calculation of seepage rate into each stratum of
soil encountered in pit sidewall by reference to Table 5-8. Only
pervious side-wall area below the inlet shall be considered. In
order to calculate a sidewall seepage rate a representative
number of soil explorations shall be evaluated to adequately
identify the type and depth of each soil stratum expected
throughout the absorption area. In general, a minimum of 5
explorations will be evaluated. This information shall be
provided in the engineering report.
B. For the purposes of confirming an appropriate sidewall
seepage rate, the owner shall submit a statement describing the
character and thickness of each stratum of soil encountered
during pit construction. Soil classification and assumed seepage
rates shall be as specified in Table 5-8 except when valid
seepage measurements are available.
C. The lining may be brick, stone, block or similar
materials, at least 4 inches thick, laid in cement mortar above
the inlet and with tight butted joints below the inlet. The
annular space between the lining and the earth wall shall be
filled with crushed rock or gravel varying in diameter from 3/4
inch to 2-1/2 inches.
D. A structurally sound and otherwise suitable top shall
be provided. Structural design and materials used throughout
shall assure a durable safe structure.
E. If more than one seepage pit is provided, the
installation may be operated in series or parallel with
distribution of effluent as specified in R317-5-2.1(G).
F. For hollow lined pits, the inlet pipe should extend
horizontally at least 1 foot into the pit with a tee to divert
flow downward and prevent washing and eroding the
sidewall.
G. For filled pits a thin layer of crushed rock or gravel
ranging from 3/4 to 2-1/2 inches in diameter, free from fines,
sand, clay or organic material shall cover the coarse material to
permit leveling of the distribution pipe.
TABLE 5-6
SEEPAGE PITS CONSTRUCTION DETAILS
ITEM UNIT MINIMUM MAXIMUMGeneralsDistance betweenseepage pits feet 12(a) -Diameter ofdistribution pipe inches 4 -Size of coarsematerial inches 3/4 12Bottom of pit tomaximum groundwater feet 2 -Bottom of Pit inunsuitable soilor bedrockformations feet 4 -Hollow-lined Pits:Width of annularspace betweenlining and sidewallcontaining crushedrock (3/4 to 2-1/2inches in diameter) inches 6 -Thickness of brick,or block linings inches 4(b)Filled Pits:Depth of coarse material:Under pipe feet 4 -Over distribution pipe inches 2 -Depth of backfill overmaterial inches 6 -Footnotes:(a) See Table 5-1(b) Pre-manufactured linings may be approved with thicknesses less than 4 inches.
3.5 SEEPAGE TRENCHES (MODIFIED SEEPAGE PITS):
Seepage trenches are considered as modified seepage pits
and consist of deep trenches filled with clean, coarse material.
They shall conform to the requirements applying to seepage pits
except for the following:
A. The effective sidewall absorption area shall be
considered as the outside surface of the seepage trench (vertical
sidewall area) calculated below the inlet or distribution pipe.
Only pervious sidewall area below the inlet shall be
considered.
TABLE 5-7
SEEPAGE TRENCH DETAIL
ITEM UNIT MINIMUM MAXIMUM Seepage trench width feet 2 - Seepage trench length feet - 100 Effluent Distribution pipe Diameter inches 4 - Slope percent level level Distance between seepage trenches feet 12(a) - Footnote: (a) See Table 5-1.
TABLE 5-8
SEEPAGE TRENCHES AND PITS
ALLOWABLE SIDEWALL SEEPAGE RATES
SYMBOL AND CHARACTER OF SOIL GALLONS/ BY UNIFIED SOIL CLASSIFICATION DAY/ SYSTEM SQ. FT. Hardpan or bedrock (including fractured bedrock with little or no fines). 0 GW Well graded gravels, gravel-sand mixtures little or no fines. 1.55 GP Poorly graded gravels or gravel-sand mixtures, little or no fines. 1.55 SW Well graded sands, gravelly sand, little or no fines. 1.20 SP Poorly graded sands or gravelly sands, little or no fines. 1.20 SM Silty sand, sand-silt mixtures. 0.8 GM Silty gravels, poorly graded gravel-sand-silt mixtures. 1.0 GC Clayey gravels, gravelly-sand-clay mixtures. 0.45(a) SC Clayey sands, sand-clay mixtures. 0.45(a) ML Inorganic silts and very fine sand, rock flour, silt or clayey find sands or clayey silts with slight plasticity. 0.45(a) MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts. 0.45(a)(b) CL Inorganic clays or low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. 0.45(a)(b) CH Inorganic clays of high plasticity, fat clays. 0 OL Organic silts and organic silty clays of low plasticity. 0 OH Organic clays of medium to high plasticity, organic silts. 0 PT Peat and other highly organic silts. 0 Other Impervious formations. 0 Footnotes: (a) For the purpose of this table, whenever there are reasonable doubts regarding the suitability and estimated absorption capacities of soils, percolation tests shall be conducted in those soils in accordance with R317-4-1. Soils within the same classification may exhibit extreme variability in permeability, depending on the amount and type of clay and silt present. The following soils categories, SC,GC, and ML, MH and CL soils, may prove unsatisfactory for absorption systems, depending upon the percentage and type of fines present. (b) 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 gravels in fine-grained soils.
R317-5-4. Percolation Tests.
A. General Requirements.
1. A percolation test measures the rate which subsurface
soil absorbs water for the purpose of identifying porous soil
strata and site suitability for absorption systems, and is also a
basis for estimating the design criteria of such systems to
insure a reasonably long lifespan.
2. While percolation tests constitute a valuable guide
for successful operation of disposal systems, considerable
judgment must be used in applying the results. Percolation test
results shall not be presumptive, prima facie, or conclusive
evidence as to the suitability for absorption systems. Such
percolation tests may be considered and analyzed as one of many
criteria in determining soil suitability for absorption systems.
There is no need for conducting percolation tests when the soil
or other site conditions are clearly unsuitable.
3. When percolation tests are made, such tests shall be
made at points and elevations selected as typical of the area in
which the absorption system will be located. Consideration should
be given to the finished grades of building sites so that test
results will represent the percolation rate of the soil in which
absorption systems will be constructed. After the suitability of
any area to be used for absorption systems has been evaluated and
approved for construction, no grade changes shall be made to this
area unless the health authority is notified and a reevaluation
of the area's suitability is made prior to the initiation of
construction.
B. Required Test Procedures.
1. Test results when required shall be considered an
essential part of plans for absorption systems and shall be
submitted on a signed "Percolation Test Certificate" or
equivalent, certifying that the tests were conducted in
accordance with these requirements, and indicating the depth and
rate of each test in minutes per inch, the date of the tests, the
logs of the soil exploration pits, a statement of the present and
maximum ground water table, and all other factors affecting
percolation test results. Percolation tests shall be conducted at
the owner's expense by or under the supervision of a
registered sanitarian, registered engineer, or other qualified
person approved by the health authority in accordance with the
following:
(a) Conditions Prohibited for Test Holes.
Percolation tests shall not be conducted in test holes
which extend into ground water, bedrock, or frozen ground. Where
a fissured soil formation is encountered, tests shall be made
under the direction of the health authority.
(b) Number and Location of Percolation Tests.
One or more tests shall be made in separate test holes on
the proposed absorption system site to assure that the results
are representative of the soil conditions present.
Where questionable or poor soil conditions exist, the
number of percolation tests and soil explorations necessary to
yield accurate, representative information shall be determined by
the health authority and may be accepted only if conducted with
an authorized representative present.
(c) 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 absorption system.
2. Test Procedure for Sandy or Granular Soils
For tests in sandy or granular soils containing little or
no clay, 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 1
hour.
(c) If 6 inches of water seeps away in less than 10
minutes a shorter time interval between measurements shall be
used, but in no case shall the water depth exceed 6
inches.
(d) The final water level drop shall be used to calculate
the percolation rate.
3. Test Procedure for Other Soils Not Meeting the Above
Requirements.
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 4-hour period by refilling whenever necessary.
Water remaining in the hole after 4 hours shall 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 which 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 4 hours unless 2 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 clear water to a point
not more than 6 inches above the gravel whenever it becomes
nearly empty.
(d) Adjustments of the water level shall not be made
during the last 3 measurement periods except to the limits of the
last water level drop.
(e) When the first 6 inches of water seeps away in less
than 30 minutes, the time interval between measurements shall be
10 minutes, and the test run for 1 hour.
(f) The water depth shall not exceed 6 inches at any time
during the measurement period.
(g) The drop that occurs during the final measurement
period shall be used in calculating the percolation
rate.
4. 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 or fractions thereof.
5. Using Percolation Rate to Determine Absorption
Area.
The minimum or slowest percolation rate shall be used in
calculating the required absorption area.
C. Recommendations to Enhance Test Procedures.
1. 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
should 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.
2. 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 which extend to a depth approximately 6 inches
above the strata to be tested.
3. Preparation of Percolation Test Hole. Carefully
roughen or scratch the bottom and sides of the hole with a knife
blade or other sharp pointed instrument in order to remove any
smeared soil surfaces and to provide an open, natural soil
interface into which water may percolate. Nails driven into a
board will provide a good instrument to scarify the sides of the
hole. Remove all loose soil from the bottom of the hole. Add up
to 3 inches of clean coarse sand or pea-sized 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 coarse gravel.
4. 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 increase 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.
5. 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.
6. 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.
]R317-5. Large Underground Wastewater Disposal (LUWD) Systems.
R317-5-1. Authority, Purpose, Scope, Jurisdiction, Waiver Approval and Administrative Requirements.
1.1. Authority.
Construction and operating permits and approvals are issued pursuant to the provisions of Utah Water Quality Act Sections 19-5-104, 19-5-106, 19-5-107 and 19-5-108. Violation of these permits or approvals including compliance with the conditions thereof, or beginning construction, or modification without the director's approval, is subject to the penalties provided in Section 19-5-115.
1.2. Purpose.
A. The purpose of this rule is to protect the public health and the environment from potential adverse effects from large underground wastewater disposal systems within the boundaries of Utah.
B. This rule incorporates specific provisions contained in Rule R317-4 that are referenced herein, and pertinent to large underground wastewater disposal (LUWD) systems for the purpose of providing minimum design standards. Where the engineered design includes information supporting a deviation from the minimum requirements within this rule or referenced to in Rule R317-4, then the engineer may request a waiver. This rule also establishes the administrative requirements for obtaining from the division a LUWD system:
1. approval-in-concept;
2. construction permit;
3. authorization to use; and
4. operating permit
1.3 Scope.
This rule applies to large underground wastewater disposal systems designed to handle more than 5,000 gallons per day of domestic wastewater, or wastewater that originates in multiple units under separate ownership (except condominiums), or any other underground wastewater disposal system not covered under the definition of an onsite wastewater system per Rule R317-4.
A. The engineer shall use recognized practice standards for wastewater treatment to increase long term performance and lessen potential impacts to public health and the environment. Depending on site-specific characteristics, the division may require a LUWD system to pretreat effluent prior to disposal in the absorption system. In general, systems with high waste strength or flows over 15,000 gpd should consider pretreatment. Factors that should be evaluated include, but are not limited to, the following:
1. design flow (gpd)
2. highly variable flows, including seasonal fluctuations;
3. wastewater strength characteristics;
4. site characteristics.
5. proximity to ground water table, considering various soil types and separation distance;
6. ground water classification;
7. proximity to nearby drinking water sources, or location within a drinking water source protection zone; and
8. anticipated system life expectancy.
1.4. Jurisdiction. Large underground wastewater disposal systems are under the jurisdiction of the Division of Water Quality. Local Health Departments may petition the division to require local review for compliance with local requirements prior to the division initiating its review.
1.5 Waiver.
The director may grant a waiver from the minimum requirements stated in this rule, subject to site-specific consideration and justification, but not overriding the safeguarding of public health, protection of water quality or engineering practice. The intent of the waiver is to allow the engineer to utilize site specific information, recognized practice standards, or other acceptable justification while designing an appropriate LUWD system for the property. The engineer is encouraged to discuss waivers with the division staff prior to formal application for feasibility determination review.
R317-5-2. Definitions.
2.1. Definitions found in Rules R317-1 and R317-4 apply to large underground wastewater disposal systems except where specifically replaced by the following definitions:
"Alternative system" means a LUWD system that is not a conventional system.
"Building sewer" means the pipe that carries wastewater from the building to a public sewer, a LUWD system, or other point of dispersal. It sometimes is synonymous with "house sewer".
"Conventional system" means a LUWD system typically consisting of a building sewer, septic tank, and an absorption system utilizing absorption trenches, absorption beds, or deep wall trenches.
"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 LUWD system.
"Malfunctioning or failing system" means a LUWD system that is not functioning in compliance with the requirements of this rule and may include:
1. absorption systems that seep or flow to the surface of the ground or into waters of the state;
2. systems that overflow from any of their components;
3. systems that cause backflow into any portion of a building drainage system;
4. systems discharging effluent that does not comply with applicable effluent discharge standards of its operating permit;
5. leaking septic tanks; or
6. noncompliance with standards stipulated in 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 a LUWD system at that site.
"Mound system" means an alternative LUWD 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.
"Packed bed media system" means an alternative LUWD 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.
"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 LUWD system constitutes a public health hazard.
"Sand lined trench system" means an alternative LUWD system consisting of a series of narrow excavated trenches utilizing sand media and pressure distribution.
"Unapproved LUWD system" means any LUWD system that is deemed by the division to be any of the following:
1. installation without the required division oversight, permits, or inspections;
2. repairs to an existing system without the required division oversight, permits, or inspections; or
3. alteration to an existing system without the required division oversight, permits, or inspections.
"Waiver" means an acceptable deviation from the requirements established within this rule or referenced rules. The waiver must be acceptable to division staff based on the engineer providing adequate design justification to demonstrate that the deviation proposed will not override the safeguarding of public health, the protection of water quality, or the protection of the receiving environment. Waiver requests should be based on acceptable engineering practice and standards.
R317-5-3. General Standards, Prohibitions, Requirements, and Enforcement.
3.1. Failure to Comply With Rules.
Any person failing to comply with this rule shall be subject to enforcement action as specified in Sections 19-5-115 and 26A-1-123.
3.2. Feasibility.
LUWD systems are not feasible in some areas and situations. If property characteristics indicate conditions that may fail in any way to meet the requirements specified herein, the use of a LUWD system shall be prohibited.
3.3. Prohibited Flows.
No ground water drainage, drainage from roofs, roads, yards, or other similar sources shall discharge into any portion of a LUWD system, but shall be disposed of so they will in no way affect the system. Non-domestic wastes such as chemicals, paints, or other substances that are detrimental to the proper functioning of a LUWD system may not be disposed of in such systems.
3.4. Increased Flows Prohibited.
Wastewater flow may not exceed the design flow of a LUWD system.
3.5. Property Lines Crossed.
Privately owned LUWD systems, including replacement areas, shall be located on the same lot as the building served unless, when approved by the division, a perpetual utility easement and right-of-way is established and recorded on an adjacent or nearby lot for the construction, operation, and continued maintenance, repair, alteration, inspection, relocation, and replacement of a LUWD system, including all rights to ingress and egress necessary or convenient for the full or complete use, occupation, and enjoyment of the granted easement. The easement shall be large enough to accommodate the proposed LUWD system and replacement area. The easement shall meet the setbacks specified in Section R317-4-13 Table 2.
3.6. Initial Absorption Area and Replacement Area.
A. All properties that utilize LUWD systems shall be required to have a replacement area.
B. The absorption area, including installed system and replacement area, may not be subject to activity that is likely to adversely affect the soil or the functioning of the system. This may include vehicular traffic, covering the area with asphalt, concrete, or structures, filling, cutting or other soil modifications.
3.7. Operation and Maintenance.
Owners of a LUWD systems shall operate, maintain, and service their systems according to the standards of this rule.
3.8. No Discharge to Surface Waters or Ground Surface.
Effluent from any LUWD system may not be discharged to surface waters or upon the surface of the ground. Wastewater may not be discharged into any abandoned or unused well, or into any crevice, sinkhole, or similar opening, either natural or artificial.
3.9. Repair of a Malfunctioning or Unapproved System.
Upon determination by the regulatory authority that a malfunctioning or unapproved LUWD wastewater system creates or contributes to any dangerous or unsanitary condition that may involve a public health hazard, or noncompliance with this rule, the regulatory authority shall order the owner to take the necessary action to cause the condition to be corrected, eliminated or otherwise come into compliance.
A. For malfunctioning systems, the regulatory authority shall require and order:
1. all necessary steps, such as maintenance, servicing, repairs, and replacement of system components to correct the malfunctioning system, to meet all rule requirements to the extent possible and may not create any new risk to the environment or public health;
2. effluent quality testing as required by Subsection R317-5-9.2.D;
3. evaluation of the system design including non-approved changes to the system, the wastewater flow, and biological and chemical loading to the system;
4. additional tests or samples to troubleshoot the system malfunction.
3.10. Procedure for Wastewater System Abandonment. Whenever the use of a LUWD system has been abandoned or discontinued, the owner of the real property on which such wastewater system is located shall render it safe by having the septic tank, any other tanks, hollow seepage pit, or cesspool wastes pumped out or otherwise disposed of in an approved manner. Within 30 days the tanks shall be:
A. crushed in place and the void filled;
B. completely filled with earth, sand, or gravel; or
C. removed and backfilled.
3.11. Septage Management.
A person shall only dispose of septage, or sewage contaminated materials in a location or manner in accordance with the requirements of the division and any local agencies having jurisdiction.
3.12. Multiple Units Under Separate Ownership (except condominiums).
The common components of the LUWD system, including the reserve absorption area, shall be under the sponsorship of a body politic.
A. The subsurface absorption system shall be designed and constructed to provide duplicate capacity, meaning two independent systems. Each system shall be designed to accommodate the total anticipated maximum daily flow. The duplicate system shall be designed with appropriate valving, etc., to allow for periodic alternation of the use of each system.
B. Sufficient land area with suitable characteristics shall be planned and 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.
3.13. Underground Injection Control.
Large underground wastewater disposal (LUWD) systems with design flow rates of 5,000 gallons per day or more are co-regulated by the Utah 1422 Underground Injection Control (UIC) Program in Rule R317-7. LUWD systems are authorized-by-rule under the UIC program provided they remain in compliance with the construction and operating permits issued according to Rule R317-5. However, if any noncompliance with these permits results in the potential for or demonstration of actual exceedance of any Utah Maximum Contaminant Levels (MCLs) in a receiving ground water, the noncompliance may also be a violation of the Utah UIC administrative rules and therefore be subject to enforcement action. Owners and operators of a large underground wastewater disposal system are required to submit UIC inventory information according to Subsection R317-7-6.4(C) using the approved form for a LUWD system.
R317-5-4. Feasibility Determination and Approval-in-Concept.
4.1. General Criteria for Determining LUWD System Feasibility.
The division shall determine the feasibility of using a LUWD system. Upon favorable determination for feasibility an approval-in-concept will be granted by the division.
A. General Information. The required information shall include:
1. situs address if available;
2. name and address of the property owner and person requesting feasibility;
3. the location, type, and depth of all existing and proposed private and public drinking water wells, and other water supply sources within 1500 feet of the proposed LUWD system;
4. the location of all drinking water source protection zones delineated on the project site;
5. the location of all existing creeks, drainages, irrigation ditches, canals, and other surface and subsurface water conveyances within 1500 feet of the proposed LUWD system;
6. the location and distance to nearest sewer, owner of sewer, whether property is located within service boundary, and size of sewer; and
7. statement of proposed use if other than a single-family dwelling.
B. If the proposed LUWD system is located in aquifer recharge areas or areas of other particular geologic concern, the division may require such additional information relative to ground water movement, or possible subsurface wastewater flow.
C. Soil and Site Evaluation.
1. Soil Exploration Pit and Percolation Test.
a. A minimum of five soil exploration pits shall be excavated to allow the evaluation of the soils. The soil exploration pits shall be constructed and soil logs recorded as detailed in Section R317-4-14 Appendix C.
b. The division may require percolation tests in addition to the soil exploration pits.
c. The division may require additional pits, tests, or both where:
i. soil structure varies;
ii. limiting geologic conditions are encountered; or
iii. the division deems it necessary.
d. The percolation test shall be conducted as detailed in Section R317-4-14 Appendix D.
e. Soil exploration pits and percolation tests shall be conducted as closely as possible to the proposed absorption system site. The division shall have the option of inspecting the open soil exploration pits and monitoring the percolation test procedure. All soil logs and percolation test results shall be submitted to the division.
f. When there is a substantial discrepancy between the percolation rate and the soil classification, it shall be resolved through additional soil exploration pits, percolation tests, or both.
g. Absorption system feasibility and sizing shall be based on Section R317-4-13 Table 5 or 6.
2. Wind-Blown Sand.
The extremely fine grained wind-blown sand found in some parts of Utah shall be deemed not feasible for LUWD systems unless pretreatment is provided, as percolation test results in wind-blown sand will generally be rapid, but experience has shown that this soil has a tendency to become sealed with minute organic particles within a short period of time.
3. Suitable Soil Depth.
For conventional systems, effective suitable soil depth shall extend at least 48 inches or more below the bottom of the dispersal system to bedrock formations, impervious strata, or excessively permeable soil. Some alternative LUWD systems may have other requirements.
4. Ground Water Requirements.
The elevation of the anticipated maximum ground water table shall meet the separation requirements of the anticipated absorption systems.
a. Maximum Ground Water.
Maximum ground water table shall be determined where the anticipated maximum ground water table, including irrigation induced water table, might be expected to rise closer than 48 inches to the elevation of the bottom of a LUWD system. Maximum ground water table shall be determined where alternative LUWD wastewater systems may be considered based on groundwater elevations. The maximum ground water table shall be determined by the following.
i. Regular monitoring of the ground water table, or ground water table, perched, in an observation well for a period of one year, or for the period of the maximum groundwater table.
(1) Previous ground water records and climatological or other information may be consulted for each site proposed for a LUWDS system and may be used to adjust the observed maximum ground water table elevation.
ii. Direct visual observation of the maximum ground water table in a soil exploration pit for:
(1) evidence of crystals of salt left by the maximum ground water table; or
(2) chemically reduced iron in the soil, reflected by redoximorphoric features i.e., a mottled coloring.
(3) Previous ground water records and climatological or other information may be consulted for each site proposed for a LUWD system and may be used to adjust the observed maximum ground water table elevation in determining the anticipated maximum ground water table elevation.
iii. In cases where the anticipated maximum ground water table is expected to rise to closer than 34 inches from the original ground surface and an alternative LUWD system would be considered, previous ground water records and climatological or other information shall be used to adjust the observed maximum ground water table in determining the anticipated maximum ground water table.
b. Curtain Drains.
A curtain drain or other effective ground water interceptor may be allowed as an attempt to lower the groundwater table to meet the requirements of this rule. The division shall require that the effectiveness of such devices in lowering the ground water table be demonstrated during the season of maximum ground water table.
5. Ground Slope.
Absorption systems may not be placed on slopes where the addition of fluids is judged to create an unstable slope.
a. Absorption systems may be placed on slopes between 0% and 25%, inclusive.
b. Absorption systems may be placed on slopes greater than 25% but not exceeding 35% if:
i. all other requirements of this rule can be met;
ii. effluent from the proposed system will not contaminate ground water or surface water, and will not surface or move off site before it is adequately treated to protect public health and the environment;
iii. no slope will fail, and there will be no other landslide or structural failure if the system is constructed and operated adequately, even if all properties in the vicinity are developed with a LUWD system; and
iv. a report is submitted by a professional engineer or professional geologist that is licensed to practice in Utah. The report shall be imprinted with the engineer's or geologist's registration seal and signature and shall include the following.
(1) Predictions and supporting information of ground water transport from the proposed system and of expected areas of ground water mounding.
(2) A slope stability analysis that shall include information about the geology of the site and surrounding area, soil exploration and testing, and the effects of adding effluent.
(3) The cumulative effect on slope stability of added effluent if all properties in the vicinity were developed with LUWD systems.
c. Absorption systems may not be placed on slopes greater than 35%.
6. Other Factors Affecting a LUWD System Feasibility.
a. The locations of all rivers, streams, creeks, dry or ephemeral washes, lakes, canals, marshes, subsurface drains, natural storm water drains, lagoons, artificial impoundments, either existing or proposed, that will affect building sites, shall be provided.
b. Areas proposed for LUWD wastewater systems shall comply with the setbacks in Section R317-4-13 Table 2.
c. If any part of a property lies within or abuts a flood plain area, the flood plain shall be shown within a contour line and shall be clearly labeled on the plan with the words "flood plain area".
7. Unsuitable.
Where soil and other site conditions are clearly unsuitable for the placement of a LUWD system, there is no need for conducting soil exploration pits or percolation tests.
R317-5-5. Engineering Reports, Plans and Construction Permits.
All engineering reports, plans and specifications shall be prepared by a registered professional engineer licensed to practice in the State of Utah and certified Level 3 in accordance with Rule R317-11.
5.1 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 as described in feasibility determination and approval-in-concept of Section R317-5-4.
5.2. Plan Review.
Submission of plans for review. Plans for new, alterations, repairs and replacements of large underground wastewater disposal systems shall be submitted to the division for review as required by Rule R317-1 and include the following:
A. Local Health Departments Requirements.
It is the applicant's responsibility to ensure that a LUWD System application to the division is in compliance with local health department requirements regarding the location, design, construction and maintenance of a LUWD system prior to the applicant submitting a request for a construction permit to the division. Where the petition has been approved by the director, the applicant is required to submit documentation that the local health department has approved the proposed LUWD system before a construction permit may be issued.
B. Information Required.
Plans submitted for review shall be drawn to scale, 1" = 10', 20' or 30', or other scale as approved by the division. Plans shall be prepared in such a manner that the contractor can read and follow them in order to install the system properly. Depending on the individual site and circumstances, or as determined by the division, some or all of the following information may be required.
1. Applicant Information.
a. The name, current address, and telephone number of the applicant.
b. Complete address, legal description of the property, or both to be served by this LUWD system.
2. LUWD System Site Plan.
a. Submittal date of plan.
b. North arrow.
c. Lot size and dimensions.
d. Legal description of property.
e. Ground surface contours, preferably at 2 foot intervals, of both the original and proposed final grades of the property, or relative elevations using an established bench mark.
f. Location and explanation of type of dwelling(s) or structure(s) to be served by a LUWD system.
g. Location and dimensions of paved and unpaved driveways, roadways and parking areas.
h. Location and dimensions of the essential components of the wastewater system including the replacement area for the absorption system.
i. Location of all soil exploration pits and all percolation test holes.
j. Location of building sewer and water service line to serve the building.
k. Location of sewer mains, manholes, clean-outs, and other appurtenances.
l. Location of easements or drainage right-of-ways affecting the property.
m. Location of all intermittent or year-round streams, ditches, watercourses, ponds, subsurface drains, etc. within 100 feet of proposed LUWD system.
n. The location, type, and depth of all existing and proposed water supply sources
o. Delineation of all drinking water source protection zones located on the project site.
p. Distance to nearest public water main and size of main.
q. Distance to nearest public sewer, size of sewer, and whether accessible by gravity.
3. Statement with Site Plan.
Statement indicating the source of culinary water supply, whether a well, spring, non-public or public system, its location and distances from all LUWD systems.
4. Soil Evaluation.
a. Soil Logs, Percolation Test Certificates, or both.
b. Statement with supporting evidence indicating the maximum anticipated ground water table and the flooding potential for LUWD system sites.
5. Relative Elevations.
Show relative elevations of the following, using an established bench mark.
a. Building drain outlet.
b. The inlet and outlet inverts of any septic tanks.
c. Septic tank access cover, including height and diameter of riser, if used.
d. Pump tank inlet, if used, including height and diameter of riser.
e. The outlet invert of the distribution box, if provided, and the ends or corners of each distribution pipe lateral in the absorption system.
f. The final ground surface over the absorption system.
6. System Design.
Details for said site, plans, and specifications are listed in Design in Section R317-4-6.
a. Schedule or grade, material, diameter, and minimum slope of building sewer and effluent sewer.
b. Septic tank and pump tank capacity, design, cross sections, etc., materials, and dimensions. If tank is commercially manufactured, state the name and address of manufacturer.
c. Absorption system details, including the following:
i. details of drop boxes or distribution boxes, if provided;
ii. schedule or grade, material, and diameter of distribution pipes;
iii. length, slope, and spacing of each absorption system component;
iv. maximum slope across ground surface of absorption system area;
v. distance of absorption system from trees, cut banks, fills, or subsurface drains; and cross section of absorption system showing the:
(1) depth and width of absorption system excavation;
(2) depth of distribution pipe;
(3) depth of filter material;
(4) barrier material, i.e., synthetic filter fabric, straw, etc., used to separate filter material from cover; and
(5) depth of cover.
d. Pump, if provided, details as referenced in Section R317-4-14 Appendix B.
e. If an alternative LUWD system is designed, include all pertinent information to allow plan review and permitting for compliance with this rule.
C. Plans Submitted.
1. All applicants requesting plan approval for a LUWD shall submit two copies of the above required information to enable the division to retain one copy as a permanent record.
2. Applications may be rejected if proper information is not submitted.
5.3. Construction Permit Required.
No person shall make or construct any device for treatment or discharge of wastewater without first receiving a permit to do so from the director.
R317-5-6. Design Requirements.
6.1. Shall meet the requirements of Section R317-4-6, with these exceptions:
A. When a LUWD serves multiple single family dwellings the wastewater flow shall be estimated at 400 gpd per dwelling.
B. Minimum separation distance from the bottom of the absorption trenches to the anticipated maximum ground water table is 48 inches. If a mound, sand lined trench, or packed bed pretreatment unit is designed and installed on the LUWD system, the horizontal separation distance may be reduced to 24 inches.
6.2. Components Required in a LUWD System:
A. A septic tank;
B. An effluent filter;
C. A pressurized subsurface disposal system.
1. 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.
2. Pressurized systems require cleanouts at the end of pressurized laterals and typically require a dosing chamber or dosing tank.
3. The Utah Guidance for Performance, Application, Design, Operation & Maintenance: Pressure Distribution Systems document shall be used for design requirements, along with the following:
a. Dosing pumps, controls and alarms shall comply with Section R317-4-14 Appendix B.
b. Pressure distribution piping.
i. All pressure transport, manifold, lateral piping, and fittings shall meet PVC Schedule 40 standards or equivalent.
ii. The ends of lateral piping shall be constructed with sweep elbows or an equivalent method to bring the end of the pipe to the final grade. The ends of the pipe shall be provided with threaded plugs, caps, or other devices acceptable to the division to allow for access and flushing of the lateral.
D. Accessibility components to insure proper maintenance and servicing. These include that all tanks shall have access risers to the surface of the ground; and absorption field inspection ports.
E. 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.
R317-5-7. Construction and Installation.
Shall meet the requirements of Section R317-4-7.
R317-5-8. Final Inspection and Authorization to Use.
8.1. Final inspection.
Upon completion of construction, but before backfilling, the system designer must notify the division of completion and schedule a final inspection with the division. Where the local health department has the authority to issue operating permits they shall be included in the final inspection. The final inspection shall meet the requirements of Section R317-4-8. No wastewater may be introduced into a LUWD system until an authorization to use has been issued by the division.
8.2. Authorization to Use
The following documents, sealed by the engineer, must be provided to the division in order to receive authorization to use:
A. Written certification that the system was installed in accordance with the construction permit and any approved change orders.
B. Two record drawings of the completed system.
C. Two Operation & Maintenance Manuals. Manuals must include details of:
1. individuals of contact for the installed system;
2. list of all key components of the system;
3. maintenance and service instructions of each component;
4. schedule of maintenance inspections and servicing.
D. Written recommendation to the owner to place the facilities into service, pending issuance of the authorization to use by the division.
R317-5-9. Operation and Maintenance.
9.1. Operation and maintenance shall be provided by the owner to ensure the disposal system is functioning properly at all times.
9.2. The owner is responsible for maintaining a LUWD system and for performing periodic inspections, servicing and monitoring of its system as detailed in the issued operating permit, including the following:
A. Any new system installed after April 2009 must have a written operation and maintenance manual document describing the treatment and disposal system and outlining routine maintenance procedures, including checklists and maintenance logs needed for proper operation of the system.
B. Each LUWD Conventional System shall be assessed after the first year of operation and annually thereafter.
C. Each LUWD Pressure Distribution System shall be inspected as outlined in Section R317-4-23 Tables 7.1 and 7.2.
D. LUWD Alternative Systems.
1. Each alternative system shall be inspected as outlined in Section R317-4-13 Tables 7.1 and 7.2.
2. Each packed bed media system shall be sampled a minimum of every six months as outlined in Section R317-4-13 Table 7.3.
a. The grab sample shall be taken before discharge to an absorption system.
b. Effluent not meeting the standards of Section R317-4-13 Table 7.3, shall be followed with two successive weekly tests of the same type within a 30 day period from the first exceedance.
3. If two successive samples exceed the minimum standards, the system shall be deemed to be malfunctioning, and shall require further evaluation and a corrective action plan, see Subsection R317-5-3.9.
R317-5-10. Operating Permits and Annual Inspection Reports.
10.1. Operating Permit required.
An operating permit is required for all LUWD 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 director or, by delegated authority, the local health department having jurisdiction, and shall be effective for a period not to exceed 5 years from the date of issuance.
10.2. Local Health Department Authority to Issue Operating Permits.
Local health departments may request delegated authority to administer the operating permit program. The request must include an agreement to implement and enforce inspection, servicing, monitoring, and reporting requirements of this rule. The local health department must submit an annual report on or before September 1 of each calendar year, to the division 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.
10.3. Annual Inspection Report.
The owner of a LUWD system shall summit an annual inspection report 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 on all requirements listed in the operating permit. As a minimum, the report shall include the following items:
A. Facility name and address; owner name, address, and phone number;
B. List of facility components, e.g., septic tank, pump tank, gravel drainfield trench, gravelless chambers, pressure drainfield, etc.;
C. Design flow in gallons per day and number and type of connections;
D. Type of waste treated and disposed, i.e., residential, restaurant, other commercial establishment, etc.;
E. Checklist of inspections performed including the date of the inspection and a list of findings. The report must include, where pertinent:
1. measured sludge and scum levels;
2. date tanks were last pumped;
3. verify pumps, floats; and control panel are operating as designed;
4. date pump filter last cleaned;
5. date pressure laterals last cleaned and flushed and squirt height recorded;
6. any surfacing in absorption field; and
7. any observed or suspected system malfunction;
F. Packed Bed media system sampling results, where pertinent;
G. Name of the certified individual per Rule R317-11 conducting the inspection;
H. Signature of owner or certified operator, and date.
KEY: water pollution, large underground wastewater, sewerage, engineering
Date of Enactment or Last Substantive Amendment: [September 24, 2015]2014
Notice of Continuation: June 18, 2012
Authorizing, and Implemented or Interpreted Law: 19-5
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/2014/b20140215.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.
Text to be deleted is struck through and surrounded by brackets ([example]). Text to be added is underlined (example). Older browsers may not depict some or any of these attributes on the screen or when the document is printed.
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.