Wash. Rev. Code § 85.20.030
Whenever a petition is presented as provided in RCW 85.20.020, the county legislative authority shall order an election to be held to determine if the district shall be reorganized. The county legislative authority shall specify the election date which may or may not be at the normal special district general election. Notice of the election shall be posted and published, and the election shall be conducted, as for any special district election. The notice shall state the number of the district so petitioning to reorganize, the place where and the time when the election is to be held. The auditor shall certify the results of the election to the county legislative authority. If the proposition to reorganize the district is approved by a simple majority vote of the voters voting on the proposition, the district shall be reorganized as either a diking improvement district or drainage improvement district upon the county legislative authority ordering the reorganization. The district shall be liable to the county for its costs incurred for the election.
RCW 85.20.030