Wash. Rev. Code § 85.24.170
The treasurer of each county shall collect the taxes levied and assessed hereunder upon all that portion of the property situated within the county for which the treasurer is acting. The treasurer of the county in which the smaller or minor portion of the taxes are to be collected shall forward the amount collected by him or her quarterly each year on the first Monday in January, April, July, and October, to the treasurer of the county in which the larger or major portion of the taxes are to be collected. The treasurer of the county in which the larger portion of the taxes have been levied and assessed shall be the disbursing officer of such diking and drainage district, and shall pay out the funds of such district upon orders drawn by the chair and secretary of the board acting under authority of the board, and shall be the treasurer of the fund.
RCW 85.24.170