(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.