Wash. Rev. Code § 86.13.030
When such a contract shall have been entered into it shall be the duty of each of the boards of county commissioners to make for their respective counties, each year, a tax levy at a rate sufficient to meet the requirements of the contract to be performed by the county, or sufficient to provide such lesser amount as the boards of county commissioners shall agree upon for such year, to be evidenced by separate resolution of each board, and when such levy shall be made the same shall be extended upon the tax rolls of the county levying the same as other taxes shall be extended, and shall be collected in the same manner and shall be a lien upon the property as in the case of other taxes. The fund realized in each county by such tax levy shall go into a separate fund in the treasury of the county collecting the same, to be designated intercounty river improvement fund, and the entire fund so collected in the two counties shall be devoted to and be disbursed for the purposes specified in such contract and as in this chapter provided, and for no other purpose, but without regard to the particular county in which the work is performed, material required or expenditure made, it being the intent that the entire fund realized in the two counties shall be devoted to the one common purpose as if the two counties were one county and the two funds one fund. The fund in each county shall be disbursed by the county treasurer of such county upon warrants signed by the county auditor of that county. Such warrants shall be issued by order of the board of county commissioners of such county, or a majority thereof. Each county auditor shall, whenever requested by the county auditor of the other county, furnish the county auditor of the other county a statement of payments into and warrants drawn upon the fund of his or her county from time to time, and in addition thereto, each county auditor shall on the first Monday of January, April, July and October each year during the life of the contract furnish the other a complete statement thereof. Obligations incurred in the prosecution of such improvement and warrants issued shall be payable only out of said special funds, and no general obligation against or debt of either county shall be created thereby or by any contract entered into by virtue of this chapter, but it is not the intent of this chapter to deny to either county the right to have in the courts any proper proceeding to compel compliance with such contract on the part of the other county.
RCW 86.13.030
Limitation on levies: State Constitution Art. 7 s 2 (Amendments 55 and 59); chapter 84.52 RCW.