More than ever, Americans rely on independent special districts to provide public services. The special district—which can be as small as a low-budget mosquito abatement district or as vast as the Port Authority of New York and New Jersey—has become the most common form of local governance in the United States. In Governing the Tap, Megan Mullin examines the consequences of specialization and the fragmentation of policymaking authority through the lens of local drinking-water policy. Directly comparing specific conservation, land use, and contracting policies enacted by different forms of local government, Mullin investigates the capacity of special districts to engage in responsive and collaborative decision making that promotes sustainable use of water resources. She concludes that the effect of specialization is conditional on the structure of institutions and the severity of the policy problem, with specialization offering the most benefit on policy problems that are least severe. Mullin presents a political theory of specialized governance that is relevant to any of the variety of functions special districts perform. Governing the Tap offers not only the first study of how the new decentralized politics of water is taking shape in American communities, but also new and important findings about the influence of institutional structures on local policymaking.