Colo. Rev. Stat. § 37-41-133
The holder of title, or color of title, of any land adjacent to or situated within the boundaries of any irrigation district or irrigable from the ditches, canals, and irrigation works of the district may file with the board of directors of said district a petition in writing, praying that such lands be included in such district. The petition shall describe the tracts or body of land owned by the petitioners, but such description need not be more particular than is required when such lands are entered by the county assessor in the assessment book. Such petition shall be deemed to give the assent of the petitioners to the inclusion in said district of the lands described in the petition, and such petition must be acknowledged in the same manner that conveyances of land are required to be acknowledged.
C.R.S. § 37-41-133