Wash. Rev. Code § 39.34.130
Except as otherwise provided by law, the full costs of a state agency incurred in providing services or furnishing materials to or for another agency under chapter 39.34 RCW or any other statute shall be charged to the agency contracting for such services or materials and shall be repaid and credited to the fund or appropriation against which the expenditure originally was charged. Amounts representing a return of expenditures from an appropriation shall be considered as returned loans of services or of goods, supplies or other materials furnished, and may be expended as part of the original appropriation to which they belong without further or additional appropriation. Such interagency transactions shall be subject to regulation by the director of financial management, including but not limited to provisions for the determination of costs, prevention of interagency contract costs beyond those which are fully reimbursable, disclosure of reimbursements in the governor's budget and such other requirements and restrictions as will promote more economical and efficient operations of state agencies.
Except as otherwise provided by law, this section shall not apply to the furnishing of materials or services by one agency to another when other funds have been provided specifically for that purpose pursuant to law.
RCW 39.34.130
Duty to submit agreement of jurisdictional state officer or agency: RCW 39.34.050.