Wash. Rev. Code § 33.20.130
When any savings member shall have neither paid in nor withdrawn any funds from his or her savings account in the association for seven consecutive years, and his or her whereabouts is unknown to the association and he or she shall not respond to a letter from the association inquiring as to his or her whereabouts, sent by registered mail to his or her last known address, the association may transfer his or her account to a "Dormant Accounts" fund. Any savings account in the "Dormant Accounts" fund shall not participate in the earnings of the association except by permissive action of the directors of the association. The member, or his or her or its executor, administrator, successors or assigns, may claim the amount so transferred from his or her account to the dormant accounts fund at any time after such transfer. Should the association be placed in liquidation while any savings account shall remain credited in the dormant accounts fund and before any valid claim shall have been made thereto, as hereinabove provided, such savings account so credited, upon order of the director and without any other escheat proceedings, shall escheat to the state of Washington.
RCW 33.20.130
Escheats: Chapter 11.08 RCW.
Revised uniform unclaimed property act: Chapter 63.30 RCW.