# Updated Definition of “Waters of the United States”

**Action Urgency Score:** 45/100

| Field | Value |
|---|---|
| Agency | Defense Department; Engineers Corps; Environmental Protection Agency |
| Type | Proposed rule |
| Action | Supplemental notice of proposed rulemaking. |
| Published | 2026-09-09 |
| Comments close | 2026-10-09 |
| Significant | Yes (EO 12866) |
| CFR parts | 33 CFR 328, 40 CFR 120 |
| Summary | The purpose of this supplemental notice of proposed rulemaking is for the U.S. Environmental Protection Agency (EPA) and the Department of the Army ("the agencies") to supplement and seek additional comment on certain aspects of an earlier proposal, published on November 20, 2025, to revise the regulations defining the scope of waters federally covered under the Clean Water Act in light of the U.S. Supreme Court's 2023 decision in Sackett v. Environmental Protection Agency. As stated in the agencies' November 20, 2025 Notice of Proposed Rulemaking (NPRM), the agencies intend for this rulemakin |
| Document number | 2026-18317 |

## Why this score
- Significant rule under EO 12866.

Source: Federal Register API (Office of the Federal Register) (https://www.federalregister.gov/documents/2026/09/09/2026-18317/updated-definition-of-waters-of-the-united-states). Last refreshed: 2026-11-04T09:17:43.641Z.
Data from the Federal Register API; the published Federal Register document is authoritative. Informational only, not legal advice.