Numeric Nutrient Water Quality Criteria
For over 25 years, the U.S. Environmental Protection Agency has gathered data and measured the extent of nutrient pollution impacts to our nation’s waters, provided technical guidance, developed tools and policies in support of the adoption of numeric nutrient criteria by states, tribes, and territories.
Water quality criteria for nitrogen and phosphorus help to protect water bodies and restore those that are impaired by nutrient pollution. Adoption of numeric nutrient criteria allows effective monitoring of a water body for attainment of designated uses, simplifies the formulation of NPDES discharge permits, and supports restoration via development of total maximum daily loads (TMDLs).
Learn more about the EPA’s technical support, guidance, and numeric nutrient criteria recommendations, as well as the progress achieved by states and territories on the adoption of numeric nutrient criteria: