[Regulatory Update] EPA and Army Publish Supplemental Proposal on the WOTUS Definition — Additional Options Alongside the November 2025 Proposed Rule; Comments Due 9 October

On 4 September 2026, the US Environmental Protection Agency (EPA) and the Army announced a Supplemental Notice of Proposed Rulemaking (SNPRM) on the definition of "waters of the United States" (WOTUS), which determines the scope of the Clean Water Act. It seeks comment on additional regulatory options to be considered alongside the proposed rule of 20 November 2025, as the agencies work toward a final rule that fully implements the Supreme Court's 2023 decision in Sackett v. EPA. The supplemental notice was published in the Federal Register on 9 September, and comments are due by 9 October 2026. The supplemental options include one that would generally limit "relatively permanent" waters to perennial waters, and options concerning the "continuous surface connection" of wetlands. The supplemental notice does not replace the 2025 proposed rule and is not a final rule.