Water is scarcer due to climate change and in higher demand due to population growth than ever before. As if these stressors were not concerning enough, corporate investors are participating in water markets in ways that sidestep U.S. water law doctrine’s aims of preventing speculation and assuring that the holders of water rights internalize any externalities associated with changes in their rights. The operation of these new players in the shadow of traditional water law is producing elements of inefficiency and unfairness in the allocation of water rights. Resisting the polar calls for unfettered water markets, or, contrarily, the complete de-commodification of water in the face of these challenges, this Article identifies a portfolio of measures that can help get regulated water markets back on a prudent, sustainable track in our contemporary world. The portfolio includes institutional changes and measures aimed at redefining water rights. Regarding the administration and management of water rights, the Article proposes: mechanisms to address the effects on the communities where water originates, structures for joint management of surface and ground water; and tools to ensure fulfillment of all persons’ basic water needs. The changes in water rights: exclude return flows; establish character criteria for water rights holders; and define quantitative limits on the amount of water one person or entity can hold at a given time.