CWA Section 401 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.