Any notice required under this chapter shall be in writing, but service thereof is sufficient if mailed by certified mail, return receipt requested, addressed to the last known address of the parties, or sent by electronic facsimile transmission with transaction report verification and same-day United States postal service mailing of copies or service as specified in Title 316 WAC, unless otherwise provided in this chapter. Refusal of certified mail by any party shall be considered service. Prescribed time periods commence from the date of the receipt of the notice. Any party may at any time execute and deliver an acceptance of service in lieu of mailed notice.