Wash. Rev. Code § 54.04.060
The supervisor of elections or other proper officer of the county shall give notice of all elections held under this title, for the time and in the manner and form provided for city, town, school district, and port district elections. When the supervisor or other officer deems an emergency exists, and is requested so to do by a resolution of the district commission, he or she may call a special election at any time in the district, and he or she may combine or divide precincts for the purpose of holding special elections, and special elections shall be conducted and notice thereof given in the manner provided by law.
The supervisor or other officer shall provide polling places, appoint the election officers, provide their compensation, provide ballot boxes, and ballots or voting machines, poll books and tally sheets, and deliver them to the election officers at the polling places, publish and post notices of the elections in the manner provided by law, and apportion to the district its share of the expense of the election.
The manner of conducting and voting at the elections, opening and closing of polls, keeping of poll lists, canvassing the votes, declaring the result, and certifying the returns, shall be the same as for the election of state and county officers, except as otherwise provided herein.
The district commission shall certify to the supervisor a list of offices to be filled at a district election and the commission, if it desires to submit to the voters of the district a proposition, shall require the secretary of the commission to certify it at the time and in the manner and form provided for certifying propositions by the governing board of cities, towns, and port districts.
RCW 54.04.060