Wash. Rev. Code § 87.03.900
All irrigation districts in the state of Washington, and all proceedings had for the organization of any irrigation district, and all proceedings now pending in or relating to any irrigation district, shall be governed and controlled by the terms of this act, and this act shall not be construed as abridging or abrogating any of the rights or privileges of any irrigation district now organized, or being organized, and any contract, obligation, lien or charge, or bonds of any district, which may have been made, incurred, authorized or issued, prior to the taking effect of this act shall not be abridged or impaired by the terms of this act, but this act shall be construed as being a continuation of, and in aid of the previously existing laws relating to irrigation districts, except as to the sections specially repealed; and if in any instance relating to an existing district or any of its proceedings, the term of this amendatory act shall not be legally applicable, the district may proceed, and any contract, obligation, lien or charge against it may be enforced, under the terms and provisions of the law relating to irrigation districts in force and in effect prior to the taking effect of this act.
RCW 87.03.900