EPA ATTAINS Water Quality Assessment Database

EPA's national database of state water quality assessment, impairment, and TMDL information reported under the Clean Water Act.

ATTAINS houses the assessment data states submit under Clean Water Act sections 303(d) and 305(b), including which waters are listed as impaired and for which pollutants. It is the authoritative underlying dataset for identifying impaired streams in Pennsylvania, Ohio, and West Virginia that could be targeted for restoration projects. For grant writers, ATTAINS is where the documented impairment listing that most funders want to see actually lives.