Wash. Rev. Code § 35.87A.010
To aid general economic development and neighborhood revitalization, and to facilitate the cooperation of merchants, businesses, and residential property owners which assists trade, economic viability, and liveability, the legislature hereby authorizes all counties and all incorporated cities and towns, including unclassified cities and towns operating under special charters:
RCW 35.87A.010
Retroactive application- 2021 c 225 : "This act applies prospectively to any special assessment amounts collected by a lodging business as provided in section 1 of this act that are collected on or after May 10, 2021, as well as retroactively for any taxpayer who has been assessed taxes by the department of revenue prior to May 10, 2021, on any special assessment amounts collected by a lodging business as provided in section 1 of this act. Nothing in this act is intended to be construed to require or otherwise authorize a refund of taxes lawfully paid prior to May 10, 2021." [ 2021 c 225 s 4.]
Effective date- 2021 c 225 : "This act is necessary for the immediate preservation of the public peace, health, or safety, or support of the state government and its existing public institutions, and takes effect immediately [May 10, 2021]." [2021 c 225 s 5.]