The National Water-Quality Assessment (NAWQA) has produced scientific data and knowledge that is used by national, regional, state, and local agencies to develop science-based policies and management strategies to improve and protect water resources used for drinking water, recreation, irrigation, energy development, and ecosystem needs. This web page provides an overview of information about the NAWQA. It includes related research, publications, maps, software, news, and a collection of data and tools. Our surface water, groundwater, and aquatic ecosystems are priceless resources, used by people across the Nation for drinking, irrigation, industry, and recreation. The National Water-Quality Assessment (NAWQA) Project is a leading source of scientific data and knowledge for development of science-based policies and management strategies to improve and protect our water resources (Introduction).