Natural resource management will continue to be increasingly important in the face of impending climate change and population growth, respectively, impacting supply-side and demand-side constraints. Water resources, the subject of this paper, require sustainable management to provide drinking water for society, habitat and ecological water for the environment, and a myriad of industrial water uses, including agriculture, power generation, and manufacturing. In addition to technologies that increase water supply or reduce demand, the effective management of data, specific to water resources, will be crucial in the immediate and long-term future. With diverse water data generators, collectors, synthesizers, users, and policymakers, an integrated system of water data management has potential to ensure sustainable water resource management. To bring this potential to fruition, this work synthesizes published recommendations, as well as those of water experts, and best practices from examples of water data management to provide a preliminary assessment for larger ongoing efforts to improve data for water decision-making in California. Stakeholder collaboration, data standardization, increased data collection, and data transparency and accessibility are among the most common and most important recommendations for sustainably developing and managing an integrated water data management system.