This Article divides all rights into two broad categories— provision rights and participation rights. With a provision right, the government makes substantive guarantees to provide some minimum quantity and quality of a good or service. With a participation right, the government is legally proscribed from interfering with an individual citizen’s access to institutions and resources controlled or held in trust by the state, and the state is required to facilitate access to those institutions and resources equally and transparently. A growing number of national constitutions guarantee a right to water. Without exception to date, these constitutions frame the right to water as a provision right. A provision right to water raises serious problems of enforceability, equity, and sustainability. This Article critically evaluates the provision right to water and suggests an alternative participation right in water. The foundation of such a participation right in water is laid in many nations by the public trust doctrine, wherein the state holds title to water resources for the benefit of its citizens. Unlike the typical formulation and implementation of the provision right to water, a participation right is sustainable, equitable, and enforceable, and would facilitate public participation, accountability, and experimentation in water policy.