On December 7, 2021, the most recent proposed revision to the Clean Water Act’s term, “Waters of the United States” was published in the Federal Register. (See 86 FR 69372.) Comments on this proposal must be submitted by February 7, 2022. This term controls the scope of federal regulatory powers in such programs as the development of water quality standards, impaired waters, total maximum daily loads, oil spill prevention, preparedness and response plans, state and tribal water quality certification programs, the National Pollutant Discharge Elimination System (NPDES) permit program, and the Corps of Engineers’ dredge and fill program. The Environmental Protection Agency (EPA) and the Corps of Engineers have jointly drafted this comprehensive proposed rule, which also responds to President Biden’s Executive Order 13990, issued in January 2021.