Wash. Rev. Code § 85.05.390
In case lands belonging to the state, county, school district or other public corporations are benefited by any improvement instituted under the provisions of this chapter, all benefits shall be assessed against such lands, and the same shall be paid by the proper authorities of such public corporations at the times and in the same manner as assessments are called and paid in case of private persons out of any general fund of such corporation; and also all costs of repair and maintenance of such diking system shall be levied against and apportioned to such lands of such public corporations, whether owned at the time of the original improvement or subsequently acquired either by deed through delinquent tax foreclosure or otherwise, in the same manner as such costs of repair and maintenance are levied against and apportioned to lands belonging to private persons, and the same shall also be paid out of any general fund of such corporation.
RCW 85.05.390