WAC 388-101-4360. Notice—Proof of service

The department may establish proof of service by any of the following: (1) A declaration of personal service; (2) An affidavit or certificate of mailing to the service provider or to the individual to whom the notice is directed; (3) A signed receipt from the person who accepted the certified mail, the commercial delivery service, or the legal messenger service package; or (4) Proof of fax transmission.