- (1) The department shall conduct a final inspection for all LOSS and witness a pressure test of the drainfield prior to cover except for LOSS with subsurface drip systems.
- (2) The department may accept baseline pressure and flow information from the design engineer in lieu of witnessing a pressure test of subsurface drip systems.
(3) The department may allow the drainfield to be partially covered prior to the final inspection if:
- (a) The design engineer verifies the LOSS has been pretested and functions according to the approved design; and
- (b) The department is able to witness a pressure test of at least the distal orifice in every lateral during the final inspection.
[Statutory Authority: RCW 70.118B.020. WSR 11-12-035, § 246-272B-05300, filed 5/25/11, effective 7/1/11.]