Ariz. Rev. Stat. § 48-2303
A. When five or more holders of title or evidence of title to agricultural lands which have at any time been recognized as within the exterior boundaries of a United States reclamation project and which are susceptible of irrigation by the same general system of irrigation works, desire to provide for the improvement of such lands, they may propose the organization of an agricultural improvement district under the provisions of this chapter for any of the following purposes: