The CWNS communicates to Congress current estimates for the CWA–related needs of the nation and each state, including territories. The EPA conducted the first survey in 1972 and continued biennially until 1992. From 1996 to 2012, EPA conducted the survey every four years. The last survey was conducted in 2012.
EPA, in partnership with the states, conducts the CWNS to identify and document the cost of each state’s capital needs to meet the water quality and water-quality-related public health goals of the CWA.