Wash. Rev. Code § 90.48.160
Any person who conducts a commercial or industrial operation of any type which results in the disposal of solid or liquid waste material into the waters of the state, including commercial or industrial operators discharging solid or liquid waste material into sewerage systems operated by municipalities or public entities which discharge into public waters of the state, shall procure a permit from either the department or the *thermal power plant site evaluation council as provided in RCW 90.48.262(2) before disposing of such waste material: PROVIDED, That this section shall not apply to any person discharging domestic sewage only into a sewerage system.
The department may, through the adoption of rules, eliminate the permit requirements for disposing of wastes into publicly operated sewerage systems for:
if the department determines such permit requirements are no longer necessary for the effective implementation of this chapter. The department may by rule eliminate the permit requirements for disposing of wastes by upland finfish rearing facilities unless a permit is required under the federal clean water act's national pollutant discharge elimination system.
RCW 90.48.160
*Reviser's note: The "thermal power plant site evaluation council" was redesignated the "energy facility site evaluation council" by 1975-'76 2nd ex.s. c 108.