Numeric Nutrient Water Quality Criteria
For decades, the U.S. Environmental Protection Agency has measured the extent of nutrient pollution impacts to our nation’s waters and developed technical guidance, tools and policies to support state, Tribal and territorial adoption of numeric nutrient criteria into their water quality standards.
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 for effective monitoring of a water body's attainment of designated uses, simplifies the formulation of NPDES discharge permits, and supports waterbody 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 states' and territories' progress in adopting numeric nutrient criteria: