Wash. Rev. Code § 43.42.080
With the agreement of all participating permitting agencies and the permit applicant or project proponent, state permitting agencies may establish timelines to make permit decisions, including the time periods required to determine that the permit applications are complete, to review the applications, and to process the permits. Established timelines shall not be shorter than those otherwise required for each permit under other applicable provisions of law, but may extend and coordinate such timelines. The goal of the established timelines is to achieve the maximum efficiencies possible through concurrent studies and consolidation of applications, permit review, hearings, and comment periods. A timeline established under this subsection with the agreement of each permitting agency shall commit each permitting agency to act within the established timeline.
RCW 43.42.080