Ecoregional Criteria
Download GIS Data for Level III Ecoregions
The U.S. is divided into 14 distinct eco-regions.
We publish recommended water quality criteria to reduce problems associated with excess nutrients in waterbodies in specific areas of the country. We work with states and tribes to adopt regional-specific and locally appropriate water quality criteria for nutrients in lakes, reservoirs, rivers, streams, and wetlands in fourteen ecoregions.