Under Clean Water Act section 401, a federal agency may not issue a license or permit to conduct any activity that may result in a discharge into a water of the United States unless a section 401 water quality certification is issued, or certification is waived by a state or authorized Tribe. The EPA last promulgated regulations on CWA section 401 in 2023, including regulatory text addressing the scope of certification. This action will address implementation challenges and clarify regulatory uncertainty associated with the 2023 Rule, including the scope of certification. This action will increase transparency, efficiency, and predictability for co-regulators and the regulated community.