(1) When an OSS failure occurs, the OSS owner shall:
(a) Repair or replace the OSS with a conforming system or component, or a system meeting the requirements of Table IX either on the:
(i) Property served; or
(ii) Nearby or adjacent property if easements are obtained; or
(b) Connect the residence or facility to a:
(i) Publicly owned LOSS;
(ii) Privately owned LOSS where it is deemed economically feasible; or
(iii) Public sewer; or
(c) Perform one of the following when requirements in (a) and (b) of this subsection are not feasible:
(i) Use a holding tank; or
(ii) Obtain a National Pollution Discharge Elimination System or state discharge permit from the Washington state department of ecology issued to a public entity or jointly to a public entity and the system owner only when the local health officer determines:
(A) An OSS is not feasible; and
(B) The only realistic method of final dispersal of treated effluent is discharge to the surface of the land or into surface water; or
(iii) Abandon the property.
(2) Prior to repairing the soil dispersal component, the OSS owner shall develop and submit information required under WAC
246-272A-0200(1).
(3) The local health officer shall permit a system that meets the requirements of Table IX only if the following are not feasible:
(a) Installation of a conforming system or component; and
(b) Connection to either an approved LOSS or a public sewer.
(4) The person responsible for the design shall locate and design repairs to:
(a) 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(1). Pressure distribution with timed dosing in the soil dispersal component is required in all cases where a conforming system is not feasible.
TABLE IX
Treatment Component Performance Levels for Repair of OSS Not Meeting
Vertical and Horizontal Separations1
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 | |
≥ 18 < 24 | A | A | A | A | B | B | A | B | C | Conforming |
≥ 24 < 36 | A | B | B | B | C | C | B | C | C | Systems |
≥ 36 | A | B | B | B | C | C | B | C | E | |
1The treatment component performance levels correspond with those established for treatment components under the product performance testing requirements in Table III of WAC 246-272A-0110. |
2The horizontal separation indicated in Table IX is the distance between the soil dispersal component and the surface water, well, or spring. If the soil dispersal component is up-gradient of a surface water, well, or spring to be used as a potable water source, or beach where shellfish are harvested, the next higher treatment level shall apply unless treatment level A is already required. |
3On a site where there is a horizontal setback of 75 - 100 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. |
(b) Protect drinking water sources and shellfish harvesting areas;
(c) Minimize nitrogen discharge in areas where nitrogen has been identified as a contaminant of concern in the local plan under WAC
246-272A-0015;
(d) Prevent the direct discharge of sewage to groundwater, surface water, or upon the surface of the ground;
(e) Meet the horizontal separations under WAC
246-272A-0210(1) to public drinking water sources;
(f) Meet other requirements of this chapter to the maximum extent permitted by the site; and
(g) Maximize the:
(i) Vertical separation;
(ii) Distance from a well, spring, or suction line; and
(iii) Distance to surface water.
(5) Prior to designing the repair system, the designer shall consider the contributing factors of the failure to enable the repair to address identified causes.
(6) If the vertical separation is less than twelve inches, the local health officer may permit ASTM C-33 sand or coarser to be used as fill to prevent direct discharge of treated effluent to groundwater, surface water, or upon the surface of the ground.
(7) For a repair using the requirements of Table IX, disinfection may not be used to achieve the fecal coliform requirements to meet:
(a) Treatment levels A or B where there is less than eighteen inches of vertical separation;
(b) Treatment levels A or B in type 1 soils; or
(c) Treatment level C.
(8) The local health officer shall identify repair permits meeting the requirements of Table IX for the purpose of tracking future performance.
(9) An OSS owner receiving a repair permit for a system meeting the requirements of Table IX from the local health officer shall:
(a) Immediately report any failure to the local health officer;
(b) Comply with all local and state requirements stipulated on the permit.