In Washington, a process server registers with the auditor of the county where he or she resides or operates his or her principal place of business and pays a $10 fee. Washington does not have a testing or requirement for insurance or bonding.

Service of process, except when service is by publication, is done by the sheriff of the county wherein the service is made, or by his deputy, or by any person over 18 years of age who is competent to be a witness in the action, other than a party.

The divorce papers, the summons and complaint, are served together.

Personal service in a divorce means delivery to the defendant personally, or by leaving a copy of the summons at the house of his or her usual abode with some person of suitable age and discretion who lives there.

When the defendant cannot with reasonable diligence be served, the summons may be served by leaving a copy at his or her usual mailing address with a mature person who is a resident or proprietor, and by mailing a copy by first class mail, postage prepaid, to the defendant at his or her usual mailing address. The mailing provision does not allow service to be mailed to a United States postal service post office box or the person's place of employment.

Service by publication is authorized when the defendant cannot be found within the state, and upon the filing of an affidavit stating that the plaintiff believes that the defendant is not a resident or cannot be found, and that he or she has deposited a copy of the summons and complaint in the post office, directed to him or her at his or her home unless the residence is not known, and stating the defendant keeps himself or herself concealed.

When the court determines that service by mail is “just as likely” to give actual notice as service by publication, it may order that service be made by any person over 18, who is competent to be a witness, by mailing copies of the papers to the defendant at his or her last known address or any other address determined by the court. Two copies are mailed, postage prepaid, one by ordinary first class mail and the other by a form of mail requiring a signed receipt showing when and to whom it was delivered. The envelopes bear the return address of the sender. The summons contains the date it was deposited in the mail and requires the defendant to appear and answer the complaint within 90 days from the date of mailing. Service under this subsection has the same jurisdictional effect as service by publication.

Proof of service includes written acceptance or admission of the defendant, his agent or attorney, or the return of the sheriff or his deputy endorsed upon or attached to the summons. A notice of appearance, if made, shall be in writing, shall be signed by the defendant or his attorney, and shall be served upon the person whose name is signed on the summons.