RCW 58.09.120: Monuments—Requirements.

Any monument set by a land surveyor to mark or reference a point on a property or land line shall be permanently marked or tagged with the certificate number of the land surveyor setting it. If the monument is set by a public officer it shall be marked by an appropriate official designation.

Monuments set by a land surveyor shall be sufficient in number and durability and shall be efficiently placed so as not to be readily disturbed in order to assure, together with monuments already existing, the perpetuation or reestablishment of any point or line of a survey.