RCW 39.34.080: Contracts to perform governmental activities which each contracting agency is authorized to perform.

Any one or more public agencies may contract with any one or more other public agencies to perform any governmental service, activity, or undertaking which each public agency entering into the contract is authorized by law to perform: PROVIDED, That such contract shall be authorized by the governing body of each party to the contract. Such contract shall set forth fully the purposes, powers, rights, objectives, and responsibilities of the contracting parties.