2017 National Water Quality Inventory Report to Congress
The National Water Quality Inventory Report to Congress (305(b) report) draws from two complementary sources of information on water quality. First, it summarizes the results of the statistically-representative National Aquatic Resource Surveys (NARS) conducted by the EPA in partnership with state and tribal water quality agencies. Second, it provides a tally of the local, site-specific assessment results reported by states in the Integrated 303(d)/305(b) Reports submitted biennially to EPA and loaded into the Assessment and Total Maximum Daily Load Tracking and Implementation System (ATTAINS) database.