WAC 230-17-030
WAC 230-17-030. Methods of service
Parties must serve all orders, notices, pleadings, and other documents by:
(1) Personal service; or
(2) First class, registered, or certified mail; or
(3) Commercial parcel delivery service; or
(4) Electronic transmission by email as authorized by RCW 34.05.010 (19). Parties are required to provide a valid email address in any request for hearing.