Wash. Rev. Code § 65.08.050
Every cash or final receipt from any receiver, and every cash or final certificate from any register of the United States land office, evidencing that final payment has been made to the United States as required by law, or that the person named in such certificate is entitled, on presentation thereof, to a patent from the United States for land within the state of Washington, shall be recorded by the county auditor of the county wherein such land lies, on request of any party presenting the same, and any record heretofore made of any such cash or final receipt or certificate shall, from the date when this section becomes a law, and every record hereafter made of any such receipt or certificate shall, from the date of recording, impart to third persons and all the world, full notice of all the rights and equities of the person named in said cash or final receipt or certificate in the land described in such receipt or certificate.
RCW 65.08.050