Wash. Rev. Code § 17.10.900
Any weed district formed under chapter 17.04 or 17.06 RCW prior to the enactment of this chapter, continues to operate under the provisions of the chapter under which it was formed: PROVIDED, That if ten percent of the landowners subject to any such weed district, and the county noxious weed control board upon its own motion, petition the county legislative authority for a dissolution of the weed district, the county legislative authority shall provide for an election to be conducted in the same manner as required for the election of directors under the provisions of chapter 17.04 RCW, to determine by majority vote of those casting votes, if the weed district will continue to operate under the chapter it was formed. The land area of any dissolved weed district becomes subject to the provisions of this chapter. Any district assessment funds may be transferred after the dissolution election under contract to the county noxious weed control board to fund the noxious weed control program.
RCW 17.10.900