Any code city or any regional planning commission that includes a code city, when authorized by the legislative bodies of the municipalities represented by the regional planning commission, may enter into an agreement with any department or agency of the government of the United States or the state of Washington, or its agencies or political subdivisions, or any other public or private agency, to arrange for the receipt and expenditure of funds for planning in the interest of furthering the planning program.
RCW 35A.63.050