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  1. Home
  2. CWA Section 401 Certification

CWA Section 401 Regulatory Requirements

On this page:

  • Overview
  • Current Regulatory Requirements
  • Outreach Materials
  • Frequently Asked Questions
  • Previous Regulatory Requirements

Overview

Section 401 of the Clean Water Act provides states and authorized Tribes with an important tool to help protect the water quality of federally regulated waters within their borders, in collaboration with federal agencies. EPA's current regulations at 40 CFR 121 address 401 certification generally. 

The final Clean Water Act Section 401 Water Quality Certification Improvement Rule went into effect on November 27, 2023. The final rule and supporting documents, including outreach materials, are provided below.

Current Regulatory Requirements

Rule Materials

  • 2023 Clean Water Act Section 401 Water Quality Certification Improvement Rule
  • Response to Comments
  • Economic Analysis
  • Regulations (40 CFR 121)
  • Proposed Rule
    • Public Comments (Docket)
    • Pre-proposal Recommendations (Docket)
    • Tribal Consultation and Engagement (Summary)

Rule Outreach Materials

  • Press Release
  • One-Page Fact Sheet on the Final  Rule (English | Spanish)
  • Overview Fact Sheet on the Final Rule (English | Spanish)
  • Presentations and Webinars
    • Rule Overview (Video | Slides)
    • Implementation Considerations (Video | Slides)
    • General Public Webinar (Video | Slides) (Recorded on September 26, 2023)
    • Section 401 & Treatment in a Similar Manner as a State (TAS) Webinar (Video | Slides) (Recorded on October 17, 2023)
    • Certifying Authority Webinar (Video | Slides) (Recorded on September 28, 2023)
    • Federal Agency Webinar (Video | Slides) (Recorded on October 3, 2023)
  • Frequently Asked Questions

Previous Regulations

  • 2020 CWA Section 401 Certification Rule
  • 1971 EPA regulations for Section 401 (PDF)

Related Information

CWA Section 401 Overview | Outreach & Engagement Efforts | Technical Assistance Resources | Resources for when EPA serves as the Certifying Authority | Section 401(a)(2) Resources

CWA Section 401 Certification

  • CWA Section 401 Certification Overview
  • CWA Section 401 Regulatory Requirements
  • Outreach and Engagement
  • Technical Assistance
  • Resources for when EPA acts as the Certifying Authority
Contact Us about CWA Section 401 Certification
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on May 15, 2025
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