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CWA Section 401 Certification

Statutory and Regulatory Requirements for CWA Section 401 Certification

Section 401 of the Clean Water Act (CWA) 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. Section 401 of the CWA requires that, for any federally-licensed or permitted project that may result in a discharge into waters of the United States (33 USC 1341), a water quality certification be issued to ensure that the discharge complies with applicable water quality requirements or that certification be waived. EPA's regulations at 40 CFR 121 (PDF) address Section 401 certification generally. EPA also has water quality certification regulations for federally-issued CWA Section 402 permits that are subject to the Section 401 certification requirements (40 CFR 124.53-124.55 (PDF)). Other federal agencies may also have Section 401 certification regulations for their licensing and permitting programs.

On June 1, 2020, EPA finalized the "Clean Water Act Section 401 Certification Rule" to implement the water quality certification process consistent with the text and structure of the CWA. The final rule became effective on September 11, 2020. See Docket ID No. EPA-HQ-OW-2019-0405 for additional information.

Additional Materials

2019 Guidance and 1971 Rule: EPA's 2019 Guidance and 1971 certification regulations are no longer in effect.