The current drought has focused and renewed discussion about how California curtails water rights when water availability is insufficient. Prior to the 2013-14 water year, the most recent curtailment effort dates back almost 40 years to 1976-77. Since then, many changes and advances have occurred in water use, policies, and technology. New complicating issues include the growth of environmental and water quality requirements. Given the likely growing frequency of the need for water right curtailments and the centrality of curtailments to overall drought management, the State Water Resources Control Board needs a comprehensive, quantitative water rights curtailment program. Preliminary phases of such a program have already been developed and applied in the Eel and Russian River basins, including a Drought Water Right Allocation Tool (DWRAT) that estimates ideal curtailments given data sets on water rights and water availability. Extending this program to other basins, including the Sacramento-San Joaquin Delta watershed, will require decisions on water rights and water availability quantification and resolution of several ambiguous or conflicting policies. Supporting the development of DWRAT as the basis for water rights curtailment decisions will provide a long-term approach that brings structure, quantification, and transparency to a complex and difficult administrative process.