Wash. Rev. Code § 2.64.030
Commission membership shall terminate if a member ceases to hold the position that qualified him or her for appointment. Vacancies caused by disqualification or resignation shall be filled by the appointing authority for the remainder of the term. No person may serve more than two consecutive four-year terms. A person may be reappointed after a lapse of one year. A member, rather than his or her successor, shall continue to participate in any hearing in progress at the end of his or her term, or when the member ceases to hold the position that qualified him or her for appointment. The appointing authority shall appoint an alternate to serve during a member's temporary disability, disqualification, or inability to serve. No member may otherwise be removed from the commission before the end of his or her term except upon good cause found by the appointing authority.
RCW 2.64.030