Washington Revised Code Title 1. General Provisions § 1.12.060. Certified mail--Use--Electronic return receipts authorized

(1) Whenever the use of “registered” mail is authorized by this code, “certified” mail, with return receipt requested, may be used.

(2) Whenever the use of “certified mail with a return receipt requested” is authorized or required by this code, electronic return receipt delivery confirmation provided by the United States postal service may be used.