Wash. Rev. Code § 36.70.430
When it deems it to be for the public interest, or when it considers a change in the recommendations of the planning agency to be necessary, the board may initiate consideration of a comprehensive plan, or any element or part thereof, or any change in or addition to such plan or recommendation. The board shall first refer the proposed plan, change or addition to the planning agency for a report and recommendation. Before making a report and recommendation, the commission shall hold at least one public hearing on the proposed plan, change or addition. Notice of the time and place and purpose of the hearing shall be given by one publication in a newspaper of general circulation in the county and in the official gazette, if any, of the county, at least ten days before the hearing.
RCW 36.70.430