Water Quality Standards Handbook

The WQS Handbook provides a plain language discussion of the relevant regulatory and statutory requirements and the EPA’s recommendations for how states, authorized Tribes and U.S. territories can develop and implement WQS consistent with both. The WQS Handbook also serves as a one-stop resource to facilitate a nationally consistent interpretation of the EPA’s WQS regulation at Title 40, Part 131 of the Code of Federal Regulations (CFR). Finally, the WQS Handbook provides useful information for regulated entities and the public when engaging in the WQS development and implementation process.

• Draft WQS Handbook Chapters on Designated Uses, Antidegradation, and WQS Variances
• Background
• Use the Handbook
• Related Information

Draft WQS Handbook Chapters on Designated Uses, Antidegradation and WQS Variances

In 2015, the EPA revised its Part 131 WQS regulation. Based on questions received during that revision process, experiences from implementing the revised regulation, and input the EPA sought from states and authorized Tribes, the agency has updated Chapter 2 on Designated Uses, Chapter 4 on Antidegradation, and developed a new chapter on WQS Variances to include the EPA’s most recent WQS information to support implementation of the Clean Water Act.

On December 12, 2024, the EPA released three draft chapters of the WQS Handbook for public comment (Docket ID No. EPA-HQ-OW-2024-0517). In response to requests, the EPA extended the comment period twice to allow the public additional time to review the three draft WQS Handbook chapters and to prepare and submit comments. The public comment period closed on April 30, 2025. Once finalized, the EPA will provide the two revised chapters on Designated Uses and Antidegradation and one new chapter on WQS Variances in the Use the Handbook section of this webpage.

• DRAFT Chapter 2: Designation of Uses (revised chapter) (pdf) (98.4 MB, EPA-823-D-24-002) .
  This revised chapter discusses ways to express designated uses; how to designate, revise, and remove uses; how to protect downstream uses; and when to reassess designated uses.
• DRAFT Chapter 4: Antidegradation (revised chapter) (pdf) (27.95 MB, EPA-823-D-24-003) .
  This revised chapter discusses how to utilize the various tiers of antidegradation protection, how to develop an antidegradation policy, and recommendations and considerations when developing and implementing an antidegradation implementation method consistent with the EPA’s regulation.
• DRAFT Chapter: WQS Variances (new chapter) (pdf) (121.88 MB, EPA-823-D-24-001) .
  This new draft chapter reflects the EPA’s policy and guidance on the development and implementation of WQS variances consistent with the regulatory requirements in 40 CFR 131.14 for designated uses, WQS variances, and the WQS Academy.

Background

The Water Quality Standards Handbook was first issued in 1983 and provided a compilation of EPA's WQS guidance to-date.

In 1994, The Water Quality Standards Handbook: Second Edition was issued and retained all of the guidance in the 1983 handbook unless such guidance was specifically revised in subsequent years. The 1994 handbook also contained new EPA guidance that was developed between 1983 and 1994.

In 2007, the EPA updated the online version of the handbook to provide links to additional information and resources that EPA developed subsequent to 1994 in an “Updated Information” box.  In 2012, EPA revised the “Updated information” boxes to reflect any additional EPA guidance since 2007.  EPA did not revise the text of the chapters in either 2007 or 2012.

In 2014, the EPA updated the text of the online versions of Chapters 1, 5, 6, and 7 to reflect current EPA guidance, and incorporated the information from the “Updated Information” boxes.  EPA also streamlined the text of these chapters to make the document more user friendly.

In November 2017, the EPA published an update to Chapter 3 of its Water Quality Standards (WQS) Handbook. Chapter 3 contains information relevant to water quality criteria.

For any questions related to the guidance in this Handbook, please contact us. Copies of any referenced document can be obtained by selecting the hyperlink or visiting the Reference Library of Water Quality Standards Policy and Guidance Documents page.

Use the Handbook

• Chapter 1: General Provisions (pdf) (22.11 MB)  (updated 9/2014)
• Chapter 2: Designation of Uses (pdf) (757.85 KB)  (updated 2012)
  • Note: See the draft of the Revised Designated Uses Chapter
• Chapter 3: Water Quality Criteria (pdf) (16.91 MB)  (updated 2017)
  • In December 2023, EPA made minor editorial changes to Chapter 3 to improve readability and update relevant resources.
• Chapter 4: Antidegradation (pdf) (746.16 KB)  (updated 2012)
  • Note: See the draft of the Revised Antidegradation Chapter
• Chapter 5: General Policies (pdf) (15.52 MB)  (updated 9/2014)
• Chapter 6: Procedures for Review and Revision of Water Quality Standards (pdf) (21.62 MB)  (updated 8/2014)
• Chapter 7: Water Quality Standards and the Water Quality-based Approach to Pollution Control (pdf) (27.82 MB)  (updated 1/2015)