Wash. Rev. Code § 59.12.085
(2) Upon filing of an affidavit from the person or persons attempting service describing those attempts, and the filing of an affidavit from the plaintiff, plaintiff's agent, or plaintiff's attorney stating the belief that the defendant or defendants cannot be found, the court may enter an order authorizing service of the summons as follows:
[ 2014 c 3 s 1.]