Wash. Rev. Code § 89.30.265
In case any district authorized in this chapter is appointed fiscal agent of the United States or is authorized by the United States in connection with any irrigation project in which the United States is interested to make collections of money for or on behalf of the United States, such secretary and each such director and the county treasurer of the county where the organization of the district was effected shall each execute a further additional official bond in such sum respectively as the secretary of the interior may require conditioned for the faithful discharge of the duties of his or her respective office and the faithful discharge by the district of its duties as fiscal or other agent of the United States in such appointment or authorization; such additional bonds to be approved, recorded, filed, and paid for as herein provided for other official bonds.
RCW 89.30.265