This paper examines the extent to which environmental water needs, especially the needs of riparian habitats, have both been recognized and neglected in Arizona water law. Arizona manages surface water and groundwater under two different legal regimes, which ultimately lets environmental water fall between the cracks. Environmental water, the forgotten sector, demands a redevelopment in legal framework to prevent further degradation of Arizona's riparian vegetation, streambed, and habitats, which have altered hydrological patterns and significantly reduced environmental quality. In order to avoid further environmental degradation as Arizona water demands continue to grow, it is important to maintain existing legal and institutional options and develop new options for environmental preservation, restoration, and enhancement. Future opportunities and solutions include strengthening protections in existing federal regulations like the Federal Reserved Water Rights, the Clean Air Act, the Endangered Species Act, and the Wild and Scenic Rivers Act. State solutions include extending the concept of the public trust doctrine as California and Hawaii have done, and rethinking the existing appropriation of water rights to encourage conservation, and changing state law to provide for voluntary conservation transactions.