Section 246-272A-0238. Design requirements—Facilitate operation, monitoring and maintenance.

(1) The OSS must be designed to facilitate operation, monitoring and maintenance according to the following criteria:

(a) For gravity systems, septic tank access for maintenance and inspection at finished grade is required. If effluent filters are used, access to the filter at finished grade is required. The local health officer may allow access for maintenance and inspection of a system consisting of a septic tank and gravity flow SSAS to be a maximum of six inches below finished grade provided a marker showing the location of the tank access is installed at finished grade.

(b) For all other systems, service access and monitoring ports at finished grade are required for all system components. Specific component requirements include:

(i) Septic tanks must have service access manholes and monitoring ports for the inlet and outlet. If effluent filters are used, access to the filter at finished grade is required;

(ii) Surge, flow equalization or other sewage tanks must have service access manholes;

(iii) Other pretreatment units (such as aerobic treatment units and packed-bed filters) must have service access manholes and monitoring ports;

(iv) Pump chambers, tanks and vaults must have service access manholes;

(v) Disinfection units must have service access and be installed to facilitate complete maintenance and cleaning; and

(vi) Soil dispersal components shall have monitoring ports for both distribution devices and the infiltrative surface.

(c) For systems using pumps, clearly accessible controls and warning devices are required including:

(i) Process controls such as float and pressure activated pump on/off switches, pump-run timers and process flow controls;

(ii) Diagnostic tools including dose cycle counters and hour meters on the sewage stream, or flow meters on either the water supply or sewage stream; and

(iii) Audible and visual alarms designed to alert a resident of a malfunction. The alarm must be placed on a circuit independent of the pump circuit.

(2) All accesses must be designed to allow for monitoring and maintenance and shall be secured to minimize injury or unauthorized access in a manner approved by the local health officer.

[Statutory Authority: RCW 43.20.050. WSR 05-15-119, § 246-272A-0238, filed 7/18/05, effective 7/1/07.]

RCW 43.20.050. WSR 05-15-119, § 246-272A-0238, filed 7/18/05, effective 7/1/07.