Wash. Rev. Code § 17.12.080
Whenever there shall be included within any pest district lands belonging to the state or to the county the board of county commissioners shall determine the amount of the tax or assessment for which such land would be liable if the same were in private ownership for each subdivision of forty acres or fraction thereof. The assessor shall transmit to the county commissioners a statement of the amounts so due from county lands and the county commissioners shall appropriate from the current expense fund of the county sufficient money to pay such amounts. A statement of the amounts due from state lands within each county shall be annually forwarded to the commissioner of public lands who shall examine the same and if he or she finds the same correct and that the determination was made according to law, he or she shall certify the same and issue a warrant for the payment of same against any funds in the state treasury appropriated for such purposes.
The commissioner of public lands shall keep a record of the amounts so paid on account of any state lands which are under lease or contract of sale and such amounts shall be added to and become a part of the annual rental or purchase price of the land, and shall be paid annually at the time of payment of rent or payment of interest or purchase price of such land. When such amounts shall be collected by the commissioner of public lands it shall be paid into the general fund in the state treasury.
RCW 17.12.080