The installer shall:

(1) Be currently approved by the local health jurisdiction in the county where the LOSS is to be constructed.

(2) Have the following experience:

(a) Three or more years experience installing OSS; or

(b) A record of successful completion of at least one similar installation, including a pressure distribution drainfield.

(3) Maintain a copy of approved plans and specifications on-site during construction;

(4) Follow the approved plans and specifications or obtain approval from the design engineer prior to making field changes;

(5) Install sewage tanks approved by the department according to the provisions of chapter 246-272C WAC, On-site sewage system tanks;

(6) Be on the site at all times during the excavation and construction of the LOSS;

(7) Backfill and grade the site after construction to prevent surface water from accumulating over any LOSS component; and

(8) Leave the drainfield lines uncovered until the drainfield passes the department's final inspection. Driplines may be covered prior to inspection.