Updated Definition of “Waters of the United States”

What it does

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 rulemaking to provide greater regulatory certainty and increase Clean Water Act program predictability and consistency by clarifying the definition of "waters of the United States." After consideration of the public comments received on the NPRM, the agencies are issuing this notice to supplement the NPRM with additional regulatory options on certain aspects of the proposed rule.

The Engineers Corps's summary, as published in the Federal Register.

What it would change

2 parts of Title 33, 40 of the Code of Federal Regulations:

33 CFR 328, 40 CFR 120

Before this

1 earlier Federal Register document under regulation identifier 2040-AG44 since Jan. 1, 2025.

• Nov. 20, 2025 Proposed rule. Updated Definition of “Waters of the United States”

What happens next and when

Comments must be received on or before October 9, 2026.

The agency's dates, word for word.

Check it yourself

• The document in the Federal Register
• Docket EPA-HQ-OW-2025-0322 on Regulations.gov
• Title 33 on eCFR

The record as published

Source: the Federal Register (public domain). The document in the Federal Register