Wash. Rev. Code § 29A.60.260
The votes on proposed amendments to the state Constitution, recommendations for the calling of constitutional conventions and other questions submitted to the people must be counted, canvassed, and returned by each county canvassing board in the manner provided by law for counting, canvassing, and returning votes for candidates for state offices. The secretary of state shall, in the presence of the governor, within thirty days after the election, canvass the votes upon each question and certify to the governor the result. The governor shall forthwith issue a proclamation giving the whole number of votes cast in the state for and against such measure and declaring the result. If the vote cast upon an initiative or referendum measure is equal to less than one-third of the total vote cast at the election, the governor shall proclaim the measure to have failed.
RCW 29A.60.260