The design engineer or the engineer's authorized representative shall:

1. (1) Conduct inspections to:

   1. (a) Verify LOSS construction and materials conform with approved plans and specifications; and
   2. (b) Collect data for the record drawings.

2. (2) Inspect the following:

   1. (a) Poured-in-place sewage tanks construction;
   2. (b) Installation of proprietary and public domain treatment and dispersal components;
   3. (c) Installation of LOSS components in difficult conditions including, but not limited to, steep slopes and shallow soils; and
   4. (d) Placement of sand or other fill material.

3. (3) Conduct or witness LOSS component testing to verify that all results fall within acceptable limits:

   1. (a) Water tightness testing of all tanks under WAC 246-272B-05200; and
   2. (b) Pressure testing of all new collection and conveyance piping according to an acceptable industry standard; and either
   3. (c) Pressure and flow testing of the subsurface drip system to verify it functions properly prior to scheduling a LOSS final inspection by the department; or
   4. (d) Pressure testing of the drainfield to verify it functions properly prior to scheduling a LOSS final inspection by the department.
4. (4) Record baseline pressure and flow information and provide passing results to the department during the final inspection.

[Statutory Authority: RCW 70.118B.020. WSR 11-12-035, § 246-272B-05100, filed 5/25/11, effective 7/1/11.]