Discharges from municipal wastewater treatment facilities with little to no treatment for nitrogen and phosphorus are a significant source of these nutrients to surface waters throughout the country. Setting permit limits and treating the wastewater to meet specific effluent limits can substantially reduce nitrogen and phosphorus loading from these facilities, protecting local and downstream water quality as a result. The data in this indicator represent major (≥1 million gallons/day (MGD)) and non-major ("minor," <1 MGD) municipal wastewater treatment facilities with individual National Pollutant Discharge Elimination System (NPDES) permits.

Presented by state or territory of the U.S. are the counts and percentages of such facilities that have permit limits¹ or monitoring requirements only, for any nutrient pollution parameter. Please refer to the data protocol document, "Nutrient Data Compilation and Analysis Outline," for details on how the data were generated and produced.

The data tables are based on February 2016 data from EPA's Integrated Compliance Information System (ICIS) database.

• View and download a pdf version of the nutrient data tables.
• View and download a pdf version of the protocol to learn how EPA constructed the nutrient data tables.