Wash. Rev. Code § 64.08.020
Acknowledgments of deeds conveying or encumbering real estate situated in this state, or any interest therein, and other instruments in writing, required to be acknowledged, may be taken in any other state or territory of the United States, the District of Columbia, or in any possession of the United States, before any person authorized to take the acknowledgments of deeds by the laws of the state, territory, district, or possession wherein the acknowledgment is taken, or before any commissioner appointed by the governor of this state, for that purpose, but unless such acknowledgment is taken before a commissioner so appointed by the governor, or before the clerk of a court of record of such state, territory, district, or possession, or before a notary public or other officer having a seal of office, the instrument shall have attached thereto a certificate of the clerk of a court of record of the county, parish, or other political subdivision of such state, territory, district, or possession wherein the acknowledgment was taken, under the seal of said court, certifying that the person who took the acknowledgment, and whose name is subscribed to the certificate thereof, was at the date thereof such officer as he or she represented himself or herself to be, authorized by law to take acknowledgments of deeds, and that the clerk verily believes the signature of the person subscribed to the certificate of acknowledgment to be genuine.
RCW 64.08.020