Chapter 13.06
ON-SITE SEWAGE SYSTEMS

Sections:

13.06.010    Authority.

13.06.020    Administration.

13.06.030    Definitions.

13.06.040    Applicability.

13.06.050    Location.

13.06.060    Soil and site evaluation.

13.06.070    Design requirements—General.

13.06.080    Design requirements—Septic tank sizing.

13.06.090    Design requirements—Soil dispersal components.

13.06.100    Installation.

13.06.110    Inspection.

13.06.120    Record drawings.

13.06.130    Operation, monitoring, and maintenance—Food service establishments.

13.06.140    Repair of failures.

13.06.150    Septage management.

13.06.160    Certification of installers, pumpers, and maintenance service providers.

13.06.170    Waiver of state regulations.

13.06.180    Enforcement.

13.06.190    Appeals.

13.06.010 Authority.

Pursuant to the authority of RCW 70.05.060 (powers and duties of local board of health), these regulations are hereby established as minimum requirements of the Adams County board of health governing on-site sewage systems. (Res. R-34-20)

13.06.020 Administration.

A.    Chapter 246-272A WAC governs on-site sewage systems as now written or as it may be hereafter amended and this policy supplements those rules.

Where the provisions of Chapter 246-272A WAC and this policy conflict, the more strict regulation shall apply.

B.    The Adams County board of health adopts in its entirety as a rule and regulation of this board of health, the current Department Recommended Standards and Guidance for Pressure Distribution.

C.    Where the provisions of any local, state, or federal regulation shall conflict with this policy, the more strict regulation shall apply, with the order of enforcement proceeding from federal, state, then health department. (Res. R-34-20)

13.06.030 Definitions.

“ACHD” means Adams County health department.

“As-built” means record drawing.

“Denied” means the proposal has been rejected and a new application is needed to proceed with a new permitting process.

“Department” means the Washington State Department of Health.

“Designer” means an individual who designs septic systems such as a licensed septic designer or engineer, and, in limited circumstances, a homeowner.

“Fully completed application” means an application that has been accepted over the counter by Adams County health department with proper payment to Adams County health department and that has been presented as complete, with a completed application checklist, by the applicant or the applicant’s agent.

“Health officer” means the health officer of Adams County or designee.

“Local technical review committee” means a minimum of three ACHD-approved on-site sewage system professionals, to include current health officer and/or Department oversight if requested.

“Nonrestrictive caliche” refers to a lower soil horizon comprised of calcium carbonate precipitate with sufficient permeability to absorb drain field effluent. Designers may apply a maximum application rate of four-tenths of one gallon per square foot per day.

“OSS” means on-site sewage system.

“Pending” means an application status when the proposal has issues that need to be addressed and permitting is not possible until the issues are addressed.

“Permitted” means the application for an OSS has been signed by a designated employee of Adams County health department.

“Policy” refers to the Adams County health department policy regulating on-site sewage disposal and treatment.

“Septic maintenance provider” means a person qualified by the health officer through experience or by examination to evaluate the condition and functioning of the components of an on-site sewage system. A septic system installer, septic system pumper, septic system designer, or other person approved by the health officer may qualify for certification.

“Site registration” means a report normally prepared on a form provided by ACHD of the soil and terrain conditions for a lot proposed for installation of an OSS.

“Surface water” means any body of water, whether fresh or marine, flowing or contained in natural or artificial unlined depressions for significant periods of the year, including natural and artificial lakes, ponds, springs, rivers, streams, swamps, marshes, irrigation canals and tidal waters.

“Treatment standard 1” means a thirty-day average of less than ten milligrams per liter of BOD5 and ten milligrams per liter of total suspended solids and a thirty-day geometric mean of less than two hundred fecal coliform per one hundred milliliters.

“Treatment standard 2” means a thirty-day average of less than ten milligrams per liter of BOD5 and ten milligrams per liter of total suspended solids and a thirty-day geometric mean of less than eight hundred fecal coliform per one hundred milliliters. (Res. R-34-20)

13.06.040 Applicability.

A.    The health officer:

1.    Shall apply this policy to OSS treating sewage and dispersing effluent from residential sources with design flows under three thousand five hundred gallons per day;

2.    May apply this policy to OSS for nonresidential sources of sewage if treatment, siting, design, installation, and operation and maintenance measures provide treatment and effluent dispersal equal to that required of residential sources;

3.    May not apply this policy to industrial wastewater.

B.    A valid sewage system design approval, or installation permit issued prior to the effective date of the current ACHD policy:

1.    Shall be acted upon in accordance with ACHD policy in force at the time of issuance;

2.    Shall have a maximum validity period of one year from the date of issuance or remain valid for an additional year beyond the effective date of the requirements of this policy, whichever assures the most lenient expiration date; and

3.    May be modified to include additional requirements if the health officer determines that a serious threat to public health exists.

C.    This policy does not apply to facilities regulated as reclaimed water use under Chapter 90.46 RCW.

D.    A fully completed application shall be processed in the following manner:

1.    Reviewed within twenty working days;

2.    A permitted or pending decision will be made within the review time allowed in subsection (D)(1) of this section;

3.    If the application decision is pending the reasons for the status will be communicated to the designer, and the designer will be given twenty days to respond and attempt to address the reasons for the pending status;

4.    If the designer fails to address the pending status within the time allowed in subsection (D)(3) of this section a letter will be sent to the applicant; the letter must advise the applicant of the application status, prior communication of the status to the designer, reason(s) for the status decision, and that the applicant has thirty days to attempt to address the issues which led to the status decision in order to avoid permit denial; the designer will be sent a copy of the letter; and

5.    If the applicant fails to meet the requirements outlined per the letter in subsection (D)(4) of this section, the application will be denied. A written justification for denial and an explanation of the procedure for appeal will be provided by the health officer.

E.    Every place where people congregate or reside shall be provided with a means of sewage disposal acceptable to the health officer. This shall include all recreational sites and all other places where, in the opinion of the health officer, toilet facilities are necessary to protect the public health. (Res. R-34-20)

13.06.050 Location.

 

Table IV—Minimum Horizontal Separations 

Items Requiring Setback	From Edge of Soil Dispersal Component and Reserve Area	From Sewage Tank and Distribution Box	From Building Sewer, and Nonperforated Distribution Pipe
Well or suction line	100 ft.	50 ft.	50 ft.
Public drinking water well	100 ft.	100 ft.	100 ft.
Public drinking water spring measured from the ordinary high water mark	200 ft.	200 ft.	100 ft.
Spring or surface water used as drinking water source measured from the ordinary high water mark1	100 ft.	50 ft.	50 ft.
Pressurized water supply line	10 ft.	10 ft.	10 ft.
Decommissioned well (decommissioned in accordance with Chapter 173-160 WAC)	10 ft.	N/A	N/A
Surface water measured from the ordinary high water mark	100 ft.	50 ft.	10 ft.
Building foundation/in-ground swimming pool	10 ft.	5 ft.	2 ft.
Property or easement line	5 ft.	5 ft.	N/A
Interceptor/curtain drains/foundation drains/drainage ditches
Down-gradient2:	30 ft.	5 ft.	N/A
Up-gradient3:	10 ft.	N/A	N/A
Other site features that may allow effluent to surface
Down-gradient2:	30 ft.	5 ft.	N/A
Up-gradient3:	10 ft.	N/A	N/A
Down-gradient cuts or banks with less than 5 ft. of original, undisturbed soil above a restrictive layer due to a structural or textural change	50 ft.	N/A	N/A
Down-gradient cuts or banks with at least 5 ft. of original, undisturbed soil above a restrictive layer due to a structural or textural change	25 ft.	N/A	N/A
Other adjacent soil dispersal components/subsurface stormwater infiltration systems	10 ft.	N/A	N/A
Drainfield/reserve drainfield	10 ft.	5 ft.	N/A

1    If surface water is used as a public drinking water supply, the designer shall locate the OSS outside of the required source water protection area.

2    The item is down-gradient when liquid will flow toward it upon encountering a water table or a restrictive layer.

3    The item is up-gradient when liquid will flow away from it upon encountering a water table or restrictive layer.

(Res. R-34-20)

13.06.060 Soil and site evaluation.

Type 5 soil shall include nonrestrictive caliche as shown in Table V.

Table V—Soil Type Descriptions 

Soil Type	Soil Textural Classifications
1	Gravelly and very gravelly coarse sands, all extremely gravelly soils excluding soil types 5 and 6, and all soil types with greater than or equal to 90% rock fragments.
2	Coarse sands.
3	Medium sands, loamy coarse sands, loamy medium sands.
4	Fine sands, loamy fine sands, sandy loams, loams.
5	Very fine sands, loamy very fine sands; or silt loams, nonrestrictive caliche, sandy clay loams, clay loams and silty clay loams with a moderate or strong structure (excluding platy structure).
6	Other silt loams, sandy clay loams, clay loams, silty clay loams, nonrestrictive platy structure.
7 Unsuitable for treatment or dispersal	Sandy clay, clay, silty clay, strongly cemented or firm soils, soil with a moderate or strong platy structure, any soil with a massive structure, any soil with appreciable amounts of expending clays, restrictive caliche.

(Res. R-34-20)

13.06.070 Design requirements—General.

A.    On-site sewage systems may only be designed by professional engineers, licensed under Chapter 18.43 RCW or on-site sewage system designers, licensed under Chapter 18.210 RCW, except that the health officer may allow a resident owner of a single-family residence to design the septic system if the property is suitable for a gravity OSS.

B.    The nonperforated pipe in the OSS shall be bedded with soil or sand with gravel less than one-fourth inch in diameter with a minimum of four inches of this material under the pipe six inches over the pipe.

C.    The treatment standard required is determined by the texture and depth of soil as illustrated in Table VI.

D.    The public domain OSS design meeting the requirements of treatment levels A, B, C, and D is shown on Table VI A.

Table VI—New Building Sites 

Soil Type	Soil Type	Loading Rate (gal./sq. ft./day)	Vertical Separation 12" < 18"	Vertical Separation ≥ 18"< 24"	Vertical Separation ≥24"< 36"	Vertical Separation ≥36"< 60"	Vertical Separation ≥60"
1	Gravelly and very gravelly coarse sands, all extremely gravelly soils excluding soil types 5 and 6, all soil types with greater than or equal to 90% rock fragments	1.0	A Timed dosing	B Timed dosing	B Timed dosing	B Timed dosing	C Pressure
2	Coarse sands	1.0	B Timed dosing	B Timed dosing	C Pressure	E Pressure	E Gravity
3	Medium sands, loamy coarse sands, loamy medium sands	0.8	B Timed dosing	B Timed dosing	E Pressure	E Gravity	E Gravity
4	Fine sands, loamy fine sands, sandy loams, loams	0.6	B Timed dosing	B Timed dosing	E Pressure	E Gravity	E Gravity
5	Very fine sands, loamy very fine sands; or silt loams, nonrestrictive caliche, sandy clay loams, clay loams and silty clay loams with a moderate or strong structure (excluding platy structure)	0.4	B Timed dosing	B Timed dosing	E Pressure	E Gravity	E Gravity
6	Other silt loams, sandy clay loams, clay loams, silty clay loams	0.2	B Timed dosing	B Timed dosing	E Pressure	E Gravity	E Gravity
7	Sandy clay, clay, silty clay, strongly cemented or firm soils, soil with moderate or strong platy structure, any soil with a massive structure and any soil with expanding clays	Not Suitable	Not Suitable	Not Suitable	Not Suitable	Not Suitable	Not Suitable
“Gravelly”means soil with ≥ 15%, but < 35% rock fragments by volume.
“Very gravelly” means soil with ≥ 35%, but < 60% rock fragments by volume.
“Extremely gravelly” means soil with ≥ 60%, but < 90% rock fragments by volume.

 

Table VI A 

Public Domain Technology Name*	TS1	TS2	TLA	TLB	TLC	TLD	TLE	TLN
Intermittent sand filter system		✓		✓	✓	✓
Mound system		✓		✓	✓	✓
Recirculating gravel filter system					✓	✓
Sand lined trenches/bed system		✓		✓	✓	✓
Stratified sand filter system	✓	✓	✓	✓	✓

*    Listed treatment technologies meet levels of treatment performance when constructed and used according to their respective departmental recommended standards and guidance documents.

    TS1 = Treatment Standard 1, TS2 = Treatment Standard 2, TLA = Treatment Level A, TLB = Treatment Level B, TLC = Treatment Level C, TLD = Treatment Level D, TLE = Treatment Level E, TLN = Treatment Level N (See WAC 246-272A-0010).

(Res. R-34-20)

13.06.080 Design requirements—Septic tank sizing.

A.    Septic tanks must be approved by the Department and shall have an effluent filter installed in the outlet baffle.

B.    A riser or manhole shall be installed over the lids of septic tanks and pump chambers with a bolted lid extended to the level of final surface grade.

C.    Access to all septic tank outlet filters is required; the filter handle needs to be within six inches of finished grade. The pump disconnect union access needs to be within twenty-four inches of the finished grade and located in order to allow for easy removal of the pump.

D.    The required volume of the septic tank and pump chamber are shown in Table VII.

Table VII—Required Minimum Liquid Volumes of Septic Tanks and Pump Chambers for Residential Sources in Gallons 

Number of Bedrooms	1Septic Tank Size	2Pump Chamber Total Required Volume (gal.)
3	1,000	1,000
4	1,000	1,250
For each added bedroom	250	250

1    Tank volume refers to the area below the invert outlet.

2     Total required pump chamber volume is based on liquid depth of one hundred seventy-five percent of the daily design flow and the height of the pump shroud.

(Res. R-34-20)

13.06.090 Design requirements—Soil dispersal components.

A.    Maximum hydraulic loading rates shall be based on the rates described in Table VIII.

Table VIII—Maximum Hydraulic Loading Rate 

Soil Type	Soil Textural Classification Description	Loading Rate (gal./sq. ft./day)	Loading Rate (sq. ft./bedroom)
1	Gravelly and very gravelly coarse sands, all extremely gravelly soils excluding soil types 5 and 6, and all soil types with greater than or equal to 90% rock fragments.	1.0	120
2	Coarse sands.	1.0	120
3	Medium sands, loamy coarse sands, loamy medium sands.	0.8	150
4	Fine sands, loamy fine sands, sandy loams, loams.	0.6	200
5	Very fine sands, loamy very fine sands; or silt loams, sandy clay loams, clay loams, nonrestrictive caliche, and silty clay loams with a moderate structure or strong structure (excluding a platy structure).	0.4	300
6	Other silt loams, sandy clay loams, clay loams, silty clay loams.	0.2	600
7	Sandy clay, clay, silty clay and strongly cemented firm soils, soil with a moderate or strong platy structure, any soil with a massive structure, any soil with appreciable amounts of expanding clays.	Not suitable	Not suitable

B.    All SSAS shall meet the following requirements:

1.    A pressure dosing design is required for all beds.

a.    Bed width may not exceed ten feet.

b.    A bed design is allowed in soil type 4 if fine sand and in types 1, 2, and 3.

2.     Separation from edge to edge between active trenches and beds shall be four feet minimum.

C.    For SSAS with drain rock and distribution pipe:

1.    A minimum of two inches of drain rock is required above the distribution pipe;

2.    Clean gravel three-fourths inch to two and one-half inches in diameter is required;

3.    The trench sidewall below the invert of the distribution pipe must be at least six inches into original undisturbed soil; and

4.    The soil used as backfill cover over a gravel drainfield shall not have rock particles greater than six inches in diameter.

D.    For SSAS with gravelless drainfield:

1.    Gravelless chambers shall be bedded to an adequate depth with ASTM C-33 sand to assure levelness when utilized in soil type 1; and

2.    Backfill material to six inches above the top of the drainfield component shall be soil not having rock more than three inches in diameter.

E.    The health officer may permit systems consisting solely of a septic tank and a gravity SSAS in soil type 1 if all the following criteria are met:

1.    The system serves a single-family residence;

2.    The lot size is two and one-half acres or greater;

3.    Annual precipitation in the region is less than twenty-five inches per year as described by “Washington Climate” published jointly by the Cooperative Extension Service, College of Agriculture, and Washington State University (available for inspection at Washington state libraries); and

4.    The geologic conditions beneath the dispersal component must satisfy the minimum unsaturated depth requirements to ground water as determined by the local health officer. The method for determination is described by “Design Guideline for Gravity Systems in Soil Type 1” (available upon request to the Department).

F.    Gravity systems must be designed to have equal distribution to all lines.

G.    All distribution boxes are required to have access to the ground surface for service and maintenance; the distribution box shall be protected from unintended access. (Res. R-34-20)

13.06.100 Installation.

A.    All sewage disposal systems shall be installed by approved installers, with the following exceptions:

1.    With a written request, a residential system with a conventional gravity design may be installed by the resident owner of the property for a single-family dwelling as allowed under WAC 246-272A-0250(2) subject to an approval and review of the environmental staff. In no circumstance shall any nonlicensed installer be allowed to install more than one OSS in a twelve-month period. (Res. R-34-20)

13.06.110 Inspection.

A.    For all activities requiring a permit, the health officer shall:

1.    Visit the OSS site during the site evaluation, construction, or final construction inspection;

2.    Either inspect the OSS before cover or allow the designer of the OSS to perform the inspection before cover if the designer does not have a conflict of interest such as a business or family relationship with the installer of the system; and

3.    Keep the record drawings on file with the approved design documents.

B.    The person responsible for the final construction inspection shall assure the OSS meets the standards of this policy and the conditions of any authorized waiver.

C.    The installer of the septic system shall be responsible to assure that the OSS meets the approved design and system location. (Res. R-34-20)

13.06.120 Record drawings.

A.    Record drawings are required at the time of final inspection.

B.    If the record drawing is not provided at the time of final construction inspection, no additional inspections for any other OSS completed by the installer responsible will be completed until the required information is submitted. (Res. R-34-20)

13.06.130 Operation, monitoring, and maintenance—Food service establishments.

A.    An evaluation and inspection of all OSS for food establishments shall be required annually. The required annual evaluation and inspection of OSS shall be done by a septic maintenance provider authorized by the ACHD. Food service establishments that do not serve exposed foods may be exempted from these requirements by the health officer.

B.    Other OSS as determined by the health officer may also require an annual report as determined by the conditions of the permit when issued. (Res. R-34-20)

13.06.140 Repair of failures.

A.    The person responsible for the design shall locate and design repairs to meet the requirements of Table IX if the effluent treatment and soil dispersal component to be repaired or replaced is closer to any surface water, well, or spring than prescribed by the minimum separation required in Table IV of WAC 246-272A-0210. Pressure distribution with timed dosing in the soil dispersal component is required in all cases where a conforming system is not feasible.

B.    Table IX shall be amended as follows:

Table IX—Treatment Component Performance Levels for Repair of OSS Not Meeting Vertical and Horizontal Separations
1 

Vertical Separation (in inches)	Horizontal Separation2
	< 25 feet			25 < 50 feet			50 < 100 feet3			≥ 100 feet
	Soil Type			Soil Type			Soil Type			Soil Type
	1	2	3—6	1	2	3—6	1	2	3—6	1	2	3—6
< 12	A	A	A	A	A	A	A	A	B	B	B	B
≥ 12 < 18	A	A	A	A	B	B	A	B	B	Conforming System
≥ 18 < 24	A	A	A	A	B	B	A	B	C
≥ 24 < 36	A	B	B	B	C	C	B	C	C
≥ 36	A	B	B	B	C	C	B	C	E

1    The treatment component performance levels correspond with those established for treatment components under the product performance testing requirements in Table III of WAC 246-272A.

2    The horizontal separation indicated in Table IV of Section 13.06.050 is the distance between the soil dispersal component and the surface water, well, or spring. If the soil dispersal component is up-gradient of surface water, well, or spring to be used as a potable water source, the next higher treatment level shall apply unless treatment level A is already required.

3    On a site where there is a horizontal setback of seventy-five to one hundred feet between an OSS dispersal component and an individual water well, individual spring, nonmarine surface water or surface water that is not a public water source and a vertical separation of greater than twelve inches, a conforming system that complies with WAC 246-272A-0210(4) shall be installed if feasible.

(Res. R-34-20)

13.06.150 Septage management.

A.    Persons removing septage from an OSS shall:

1.    Report all activities on monthly forms designed by ACHD;

2.    Include all information requested on the monthly forms (i.e., customer name, location of dump site, etc.); and

3.    Submit all monthly reports in order to renew annual certifications. (Res. R-34-20)

13.06.160 Certification of installers, pumpers, and maintenance service providers.

A.    OSS installers and pumpers must obtain approval from the health officer prior to providing services within Adams County.

B.    The health officer may establish programs and requirements for approving maintenance service providers.

C.    An installer who fails to renew their license for two years or greater will need to retake the installer certification exam and apply as a new installer. (Res. R-34-20)

13.06.170 Waiver of state regulations.

A local technical review committee shall review mitigation measures for which waivers of the requirements specific to this policy may be granted. (Res. R-34-20)

13.06.180 Enforcement.

In addition to any other penalties prescribed by law, any person who violates or refuses or fails to comply with any of the provisions of this policy shall be deemed to have committed a civil infraction and be subject to a penalty of up to one thousand dollars. (Res. R-34-20)

13.06.190 Appeals.

A.    Any person requesting appeal of an action by ACHD staff regarding the administration of this policy may appeal in writing to the health officer within ten days of a written notice or directive of the Department. If the written appeal does not provide sufficient evidence for the health officer to change the ACHD staff decision:

1.    First Appeal. Within thirty days after receipt of an appeal, the health officer may conduct an administrative hearing in the disputed matter.

a.    The hearing may include taking evidence orally and written from ACHD staff, the party aggrieved, and witnesses.

b.    A decision will be given in writing to the person or party making the appeal.

c.    Such administrative hearing may take place sooner than thirty calendar days if the aggrieved party shows extraordinary hardship or duress caused by the ACHD staff decision.

2.    Second Appeal. Following a written request to the health officer, within ten days of the health officer’s written decision, any person not satisfied with the health officer’s decision or the results of the administrative hearing shall make a written request for a meeting with the Adams County board of health.

a.    The appellant will be provided the opportunity to address the board of health at the next regularly scheduled meeting, or sooner if the aggrieved party demonstrates extraordinary hardship or duress caused by the health officer’s decision.

b.    The matter under appeal will be decided by a majority vote of the board of health.

B.    Pending hearings or appeals shall not stay the orders of the regulatory authority. (Res. R-34-20)