Wash. Rev. Code § 49.52.090
Every person, whether as a representative of an awarding or public body or officer, or as a contractor or subcontractor doing public work, or agent or officer thereof, who takes or receives, or conspires with another to take or receive, for his or her own use or the use of any other person acting with him or her any part or portion of the wages paid to any laborer, worker, or mechanic, including a piece worker and working subcontractor, in connection with services rendered upon any public work within this state, whether such work is done directly for the state, or public body or officer thereof, or county, city and county, city, town, township, district or other political subdivision of the said state or for any contractor or subcontractor engaged in such public work for such an awarding or public body or officer, shall be guilty of a gross misdemeanor.
RCW 49.52.090
Prevailing wages must be paid on public works: RCW 39.12.020.