Wash. Rev. Code § 12.04.080
Any justice may, by appointment in writing, authorize any person other than the parties to the proceeding, or action, to serve any subpoena, summons, or notice and complaint issued by such justice; and any such person making such service shall return on such process or paper, in writing, the time and manner of service, and shall sign his or her name to such return, and be entitled to like fees for making such service as a sheriff or constable, and shall indorse his or her fees for service thereon: PROVIDED, It shall not be lawful for any justice to issue process or papers to any person but a regularly qualified sheriff or constable, in any precinct where such officers reside, unless from sickness or some other cause said sheriff or constable is not able to serve the same: PROVIDED FURTHER, That it shall be lawful for notice and complaint or summons in a civil action in the justice court to be served by any person eighteen years of age or over and not a party to the action in which the summons or notice and complaint shall be issued without previous appointment by the justice.
RCW 12.04.080
Severability-1971 ex.s. c 292: See note following RCW 26.28.010.