(1) Design engineers shall use design criteria detailed in this chapter and from generally accepted guidance and standards when designing LOSS.
(2) All sewage from a building served must be directed to the LOSS, unless the LOSS permit allows another option.
(3) LOSS must be designed to produce effluent prior to dispersal that is equal to or higher quality than STE.
(4) LOSS owners and operators are responsible for ensuring that certain substances do not enter a LOSS collection system. These include:
(a) Strong bases, acids, chlorinated solvents, or other toxic or hazardous substances;
(b) Fire or explosion hazards;
(c) Solid or viscous wastes that could plug sewer lines;
(d) Drainage from surface runoff, footing drains, roof drains, subsurface stormwater infiltration systems, swimming pools, hot tubs, and other nonsewage drains; and
(e) Industrial wastewater.
(5) Chemicals in common household products used in moderate amounts are exempt from the provisions of subsection (4) of this section.
(6) Drainage identified in subsection (4) of this section must also be prevented from entering any areas where LOSS components are located, including primary and reserve drainfield areas.
[Statutory Authority: RCW
70.118B.020. WSR 11-12-035, § 246-272B-06000, filed 5/25/11, effective 7/1/11.]