AbstractIn the US federal system, state governments play important roles between the federal and local levels in water resources planning, coordination, and regulation. How they coordinate these functions can indicate the degree of integration of their agencies and programs. A database of state programs was used to compile indicators of integration among water quality and quantity and drinking water source quality, as well as the status of comprehensive water planning. In most prior appropriation states and in some states in riparian areas, the management of water withdrawals and water quality remains in separate agencies. Some 35 of 50 states have a version of a “state water plan.” A scattered pattern of institutional arrangements shows that titles and functional coordination evolve in response to contextual situations, although state water management agencies have matured, and many have stable organizational forms. Water rights and regulatory controls for clean water and safe drinking water are firmly in place. Organizational structures are not likely to change much, but integration can be improved through management mechanisms and appropriate uses of planning, particularly at the watershed scale.Practical ApplicationsState governments are pressed to be active in water resources management because they have authority in a geographic sphere closest to the scales of watersheds, river basins, and regional aquifers. This authority is important for states to respond to new threats like climate change, worsening floods, long-term drought, and public health challenges. Like in other levels of government, the workforce in state water management agencies is mobile and requires constant capacity building. Institutional memory is especially important, and state government executives require a rapid but comprehensive view of past experiences in organizational management in regulation, planning, and interactions with the federal and state governments. The paper provides a review of these experiences, along with suggested priorities for water management enhancements that may help in the future.