All process provided for in this chapter may be served in the same manner as is provided by law for the service of process in the superior court; and it shall be the duty of any officer to whom any process may be delivered or issued, to serve the same as directed: PROVIDED, That in the service of process a copy thereof shall be delivered to the witness.
RCW 44.16.020
Service of summons: RCW 4.28.080.