Wash. Rev. Code § 36.68.510
If the service area is formed, there shall be created in the office of the county treasurer a local service area fund with such accounts as the treasurer may find convenient, or as the state auditor may direct, into which shall be deposited all revenues received by the service area from tax levy, from gifts or donations, and from service or admission charges. Such fund shall be designated "(name of county) service area No. . . . . fund." Or "(name of district) service area fund." Special accounts shall be established within the fund for the deposit of the proceeds of each bond issue made for the construction of a specified project or improvement, and there shall also be established special accounts, within the fund for the deposit of revenues raised by special levy or derived from other specific revenues, to be used exclusively for the retirement of an outstanding bond issue or for paying the interest or service charges on any bond issue.
RCW 36.68.510