These documents present EPA's nutrient criteria for Lakes and Reservoirs in Ecoregions across the country. They contain EPA's recommendations to states and authorized tribes for establishing their water quality standards. These recommended criteria are not laws or regulations - they are guidance that states and tribes may use as a starting point for the criteria for their water quality standards.

• Ecoregion I: Willamette and Central Valleys (Under development)
• Ecoregion II: Western Forested Mountains (EPA 822-B-00-007)
• Ecoregion III: Xeric West (EPA 822-B-01-008)
• Ecoregion IV: Great Plains Grass and Shrublands (EPA 822-B-01-009)
• Ecoregion V: South Central Cultivated Great Plains (EPA 822-B-01-010)
• Ecoregion VI: Corn Belt And Northern Great Plains (EPA 822-B-00-008)
• Ecoregion VII: Mostly Glaciated Dairy Region (EPA 822-B-00-009)
• Ecoregion VIII: Nutrient Poor Largely Glaciated Upper Midwest and Northeast (EPA 822-B-00-010)
• Ecoregion IX: Southeastern Temperate Forested Plains and Hills (EPA 822-B-00-011)
• Ecoregion X: Texas-Louisiana Coastal and Mississippi Alluvial Plains (Under development)
• Ecoregion XI: The Central and Eastern Forested Uplands (EPA 822-B-00-012)
• Ecoregion XII: Southeastern Coastal Plain (EPA 822-B-00-013)
• Ecoregion XIII: Southern Florida Coastal Plain (EPA 822-B-00-014)
• Ecoregion XIV: Eastern Coastal Plain (EPA 822-B-01-011)