Wash. Rev. Code § 35A.08.040
The election on the question whether to adopt a charter and become a charter code city and the nomination and election of the members of the charter commission shall be conducted, and the result declared, according to the laws regulating and controlling elections in the city. Candidates for election to the charter commission must be nominated by petition signed by ten registered voters of the city and residents therein for a period of at least two years preceding the election. A nominating petition shall be filed within the time allowed for filing declarations of candidacy and shall be verified by an affidavit of one or more of the signers to the effect that the affiant believes that the candidate and all of the signers are registered voters of the city and he or she signed the petition in good faith for the purpose of endorsing the person named therein for election to the charter commission. A written acceptance of the nomination by the nominee shall be affixed to the petition when filed with the county auditor. Nominating petitions need not be in the form prescribed in RCW 35A.01.040. Any nominee may withdraw his or her nomination by a written statement of withdrawal filed at any time not later than five days before the last day allowed for filing nominations. The positions on the charter commission shall be designated by consecutive numbers one through fifteen, and the positions so designated shall be considered as separate offices for all election purposes. A nomination shall be made for a specific numbered position.
RCW 35A.08.040