The federal regulation at 40 CFR 131.10(b) requires that “In designating uses of a water body and the appropriate criteria for those uses, the State shall take into consideration the water quality standards of downstream waters and shall ensure that its water quality standards provide for the attainment and maintenance of the water quality standards of downstream waters.” This provision requires states and authorized tribes to consider and ensure the attainment and maintenance of downstream water quality standards during the establishment of designated uses and water quality criteria in upstream waters.
The following resources are intended to provide states, territories, and tribes with helpful information on EPA’s downstream protection efforts.
- Protection of Downstream Waters in Water Quality Standards: Frequently Asked Questions (PDF)(12 pp, 3.8 MB)
- Decision Tool for Downstream Water Quality Protection
- Templates for Narrative Downstream Protection Criteria in State Water Quality Standards
- (See Templates for Narrative Downstream Protection Criteria in State Water Quality Standards )
- (See Favorable Supreme Court Decision Concerning Interstate Water Pollution, Memorandum from Raymond Ludwiszewski (Arkansas v. Oklahoma) )
- (See Response to Sierra Club Petition )
- Favorable Supreme Court Decision Concerning Interstate Water Pollution, Memorandum from Raymond Ludwiszewski (Arkansas v. Oklahoma) (PDF)(29 pp, 2 MB)
- Templates for Narrative Downstream Protection Criteria in State Water Quality Standards (PDF)(8 pp, 127 K)
- Response to Sierra Club Petition (PDF)(54 pp, 701 K)