Guidance & Policy Memos

Many documents on this web page were included to provide an historical context for current antidegradation policies and their implementation. However, all of these documents do not necessarily reflect the latest policies, procedures, or practices for applying antidegradation concepts of the Clean Water Act. Additionally, while the guidance below contains useful recommendations, they are not requirements and not binding. Your regional water quality standards coordinator can help determine what policies, guidance, and other documents are appropriate for developing antidegradation policies and implementation procedures for your state, tribe, or territory.

• EPA Policy Memos
• EPA HQ Guidance
• EPA Regional Guidance

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EPA Policy Memos

• Memorandum to Water Management Division Directors: Tier 2 Antidegradation Reviews and Significance Thresholds, August 08, 2005
• Memorandum to Water Management Division Directors: Interpretation of Antidegradation Regulatory Requirement (PDF) (7 pp, 448K) February 22, 1994
• Antidegradation Policy: ONRW (PDF) (2 pp, 54K) June 13, 1991
• Application of Antidegradation Policy to the Niagara River (PDF) (3 pp, 144K) August 4, 1989
• EPA Designation of Outstanding National Resource Waters (PDF) (8 pp, 409K) May 25, 1989
• Determination of "Existing Uses" for Purposes of Water Quality Standards Implementation (PDF) (3 pp, 157K) April 7, 1986
• Answers to Questions on Nonpoint Sources and WQS (PDF) (2 pp, 68K) March 7, 1986
• Antidegradation Policy (PDF) (6 pp, 292K) December 10, 1985
• Antidegradation Policy (PDF) (2 pp, 80K) November 22, 1985
• Interpretation of the Term "Existing Uses" Under the Antidegradation Policy (PDF) (2 pp, 54K) February 21, 1985
• Antidegradation, Wasteloads, and Permits (PDF) (2 pp, 77K) 1985
• Downgrading of Water Quality Standards (PDF) (3 pp, 99K) May 23, 1978
• Compendium of Department of the Interior Statements on Non-Degradation of Interstate Waters (PDF) (59 pp, 3.5MB) August 1, 1968

EPA HQ Guidance

• Interim Economic Guidance for Water Quality Standards: Workbook, March 1, 1995
  • Chapter 5 - Antidegradation: Role of Economic Analysis
  • Figure 5-1: Antidegradation Review
  • Table 5-1: Secondary Indicators
  • Table 5-2: Assessment of Substantial Impacts Matrix
• Water Quality Standards Handbook: Second Edition (Chapter 4: Antidegradation) (PDF) (15 pp, 1.4MB) August 1, 1994
  • see also Appendix G: Qs & As on Antideg (PDF) (17 pp, 1.3MB)
• Water Quality Standards for Wetlands: National Guidance (Chapter 5) (PDF) (66 pp, 4.4MB) July 1, 1990
• Reference Guide to Water Quality Standards for Indian Tribes (page 11) (PDF) (45 pp, 2.8MB) January 2, 1990
• Questions and Answers on Antidegradation (PDF) (16 pp, 1.3MB) August 1985

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EPA Regional Guidance

• Region 1 Guidance for Antidegradation Policy Implementation for High Quality Waters (PDF) (10 pp, 31K) March 10, 1987
• Region 5 Guidance for Antidegradation Policy Implementation for High Quality Waters (PDF) (16 pp, 354K) December 3, 1986
• Region 8 Antidegradation Guidance
  • Preface & Executive Summary (PDF) (8 pp, 228K)
  • Chapter 1 (PDF) (4 pp, 143K)
  • Chapter 2 (part 1) (PDF) (16 pp, 483K)
  • Chapter 2 (part 2) (PDF) (20 pp, 479K)
  • Chapter 3 (PDF) (4 pp, 106K)
  • Chapter 4 (PDF) (17 pp, 945K)
  • Appendices (PDF) (26 pp, 437K)
• Region 9 Antidegradation Guidance (PDF) (14 pp, 86K)

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