Antidegradation Clearinghouse

This clearinghouse is a compilation of information on antidegradation, including state, tribe, and territorial antidegradation policies, EPA guidance, regulations, and recent actions, including proposed and final federal water quality standards. The compiled antidegradation policies are from state, territorial, and authorized tribal water quality standards. These standards (and consequently, the antidegradation policies) are either EPA-approved or were effective before May 30, 2000 for Clean Water Act purposes. Additional information.

This site will be updated periodically to reflect EPA approved revisions and additions to state, tribal, and territorial antidegradation policies.

• State, Tribal & Territorial Antidegradation Policies
• Implementation Procedures
• Interstate Agencies
• Proposed & Final Rules
• Regulations
• EPA Policy and Guidance Memos

State, Tribal & Territorial Antidegradation Policies

Click on the map or drop down menus below to find state and territorial antidegradation policies. To view the designated uses of water bodies in table or map form for selected states, see the water quality standards database. For the most recent version of specific antidegradation policies and procedures please contact the appropriate regional water quality standards coordinator.

Tribal antidegradation policies

Implementation Procedures

The implementation procedures from the states listed below possess certain commendable features. However, it is important to note there are strengths and weaknesses to any implementation procedure, and that EPA does not necessarily recommend all aspects of the procedures below. Your regional water quality standards coordinator can provide assistance and technical support to help determine what antidegradation policy implementation procedures are appropriate for your state, tribe or territory.

• Colorado (PDF) (6 pp, 54K)
• Maryland (PDF) (12 pp, 90K)
• Ohio
• Oregon 

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Interstate Agencies

The links below give information about interstate agencies that help regulate water quality standards and antidegradation policy.

• Delaware River Basin Commission (DRBC)
• Interstate Environmental Commission (IEC)
• Interstate Water Commission on the Potomac River Basin (ICPRB)
• New England Interstate Water Pollution Control Commission (NEIWPCC)
• Ohio River Valley Water Sanitation Commission (ORSANCO)
• Susquehana River Basin Commission (SRBC)
• Tahoe Regional Planning Agency (TRPA)

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Proposed & Final Rules

• Federal Regulations 40 CFR 131.42 (Effective January 11, 2008): Federal Regulations establishing methods to implement Puerto Rico's antidegradation policy.
• Proposed Water Quality Standards for Oregon, 68 Fed. Reg. 58758, (Section III.E., pages 58775-58777 and section (i), page 58790), October 10, 2003
• Proposed Water Quality Standards for Kentucky, 67 Fed. Reg. 68971, November 14, 2002
• ANPRM: Water Quality Standards Regulation, (Section III.D., pages 36779-36787), July 7, 1998
• Final Water Quality Standards for Pennsylvania, 61 Fed. Reg. 64816, December 9, 1996 (withdrawn) 
• Final Water Quality Guidance for the Great Lakes System, 60 Fed. Reg. 15366, (Section IV.C. Antidegradation Provisions, page 15379), March 23, 1995

Regulations

• Water Quality Standards, 40 CFR Part 131 (PDF) (84 pp, 1.2MB) (Antidegradation policy)
• Water Quality Guidance for the Great Lakes System (PDF) (64 pp, 404K) 40 CFR part 132 {§132.4(a)(6); Appendix E to part 132}

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