Policy-makers are giving increased attention to issues associated with financing and investing in the nation's drinking water and waste-water treatment systems, which take in water, treat it, and distribute it to households and other customers, and later collect, treat, and discharge water after use. The renewed attention is due to a combination of factors. These include the financial impacts on communities of meeting existing and anticipated regulatory requirements, the need to repair and replace existing infrastructure, concerns about paying for security-related projects, and proposals to stimulate U.S. economic activity by building and rebuilding the nation's infrastructure. This book identifies a number of issues that continue to receive attention in connection with water infrastructure investment. It begins with a review of federal involvement; describes the debate about needs; and then examines key issues, including the nature of the problems to be solved, who will pay, and what the federal role is, and questions about mechanisms for delivering federal support.