Following careful reconsideration of the water quality certification rule the U.S. Environmental Protection Agency (EPA or the Agency) promulgated in 2020, the Agency is finalizing a rule revising and replacing the 2020 regulatory requirements for water quality certification under Clean Water Act (CWA) section 401. This final rule updates the existing regulations to better align with the statutory text and purpose of the CWA; to clarify, reinforce, and provide a measure of consistency with elements of section 401 certification practice that have evolved over the more than 50 years since EPA first promulgated water quality certification regulations; and to support an efficient and predictable certification process that is consistent with the water quality protection and cooperative federalism principles central to CWA section 401. An Executive order signed on January 20, 2021, entitled "Protecting Public Health and the Environment and Restoring Science to Tackle the Climate Crisis," directed the Agency to review the water quality certification rule EPA promulgated in 2020, and this final rule culminates that review. The Agency is also finalizing conforming amendments to the water quality certification regulations for EPA-issued National Pollutant Discharge Elimination System (NPDES) permits.