National Water Quality Inventory: Report to Congress (2004 Reporting Cycle)

This National Water Quality Inventory: 2004 Report to Congress, prepared under section 305(b) of the Clean Water Act, summarizes water quality reports submitted electronically by 44 states, 2 territories, and the District of Columbia to the U.S. Environmental Protection Agency (EPA) for the 2004 reporting cycle. These state water quality assessment findings are contained in EPA's Water Quality Assessment and Total Maximum Daily Load (TMDL) Information database and website, known as ATTAINS (Assessment TMDL Tracking And ImplementatioN System), for the 2004 reporting cycle. The ATTAINS database is available online at the website http://www.epa.gov/waters/ir. Summary findings of the 2004 state water quality reports are presented below. It is important to note that this information is for a relatively small subset of the nation's total waters which may not be representative of the waters that were not assessed. Because many states target their limited monitoring resources to waters that they suspect are impaired, there may be a lower percentage of impaired waters among the non-assessed (and total) waters than among the assessed waters. Information about specific sources and causes of impairment is incomplete because the states do not always report the cause or source of pollution affecting every impaired waterbody. In some cases, states may recognize that water quality does not fully support a designated use; however, they may not have adequate data to document the specific pollutant or source responsible for the impairment. EPA also made changes in how specific causes and sources are categorized for 2004, and these changes in some cases affect how the findings of causes and sources of impairment compare to findings of previous years. Readers are urged to consult the ATTAINS website for detailed listings of the causes and sources of impairment reported by states.