Wash. Rev. Code § 35A.34.230
At a time fixed by the city's ordinance or city charter, not later than the first Monday in October of the second year of each fiscal biennium, the chief administrative officer shall provide the city's legislative body with current information on estimates of revenues from all sources as adopted in the budget for the current biennium, together with estimates submitted by the clerk under RCW 35A.34.070. The city's legislative body and the city's administrative officer or the officer's designated representative shall consider the city's total anticipated financial requirements for the ensuing fiscal biennium, and the legislative body shall determine and fix by ordinance the amount to be raised the first year of the biennium by ad valorem taxes. The legislative body shall review such information as is provided by the chief administrative officer and shall adopt an ordinance establishing the amount to be raised by ad valorem taxes during the second year of the biennium. Upon adoption of the ordinance fixing the amount of ad valorem taxes to be levied, the clerk shall certify the same to the county legislative authority as required by RCW 84.52.020.
RCW 35A.34.230