Wash. Rev. Code § 53.46.030
The county canvassing board of election returns shall certify the results of the election to the board of county commissioners; and if at such election a majority of voters voting on the question of consolidation in each port district to be consolidated shall vote in favor of consolidation, the board of county commissioners shall so declare, and the port district resulting from the consolidation shall then be and become a municipal corporation of the state of Washington. The county auditor shall in such event issue a certificate of election to the successful candidate from each port commissioner district. If the proposed district includes area in two or more counties, certificates of election shall be issued by the principal county auditor, and the canvassing board of elections shall be made up of the chairs of the board of county commissioners, prosecutors, and the auditors of each county with area within the consolidated port district. Of the successful port commissioner candidates, if three are elected, the one receiving the highest number of votes shall serve until his or her successor is elected and qualified at the third subsequent regular election for port commissioner, and the ones receiving the second and third highest numbers of votes shall serve until their successors are elected and qualified at the second and first subsequent regular elections for port commissioner, respectively. If five or seven commissioners are elected, the two with the greatest number of votes shall serve until their successors are elected and qualified at the third subsequent regular election of port commissioners, the two commissioners receiving the next highest number of votes shall serve until their successors are elected and qualified at the second subsequent regular election of port commissioners; and the remaining commissioner or commissioners shall serve until their successors are elected and qualified at the next regular election of port commissioners.
RCW 53.46.030