On November 20, 2025, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps, together the “Agencies”) published a Notice of Proposed Rulemaking (Proposed Rule) in the Federal Register to revise the definition of “waters of the United States” (WOTUS) under the Clean Water Act (CWA).[1]

The Proposed Rule represents the Agencies’ second effort to implement the Supreme Court’s 2023 decision in Sackett v. EPA[2], which narrowed federal authority over wetlands. If finalized, the rule would limit federal jurisdiction, reducing the number of projects requiring Section 404 dredge-and-fill permits and Section 401 water quality certifications. Public comments are due January 5, 2026.

Background

The CWA applies to “navigable waters,” defined as “waters of the United States, including the territorial seas.”[3] But Congress did not provide a precise definition of WOTUS, leading to decades of litigation, regulatory revisions, and uncertainty.

In Sackett, the Supreme Court clarified that WOTUS includes only relatively permanent, standing, or continuously flowing bodies of water—such as streams, rivers, lakes, and oceans—and wetlands that have a continuous surface connection to those waters. Intermittent, ephemeral, or hydrologically isolated waters are generally not jurisdictional.

After Sackett, the Agencies issued their “Amended 2023 Rule”[4] to align with the Court’s guidance. Stakeholders, however, raised concerns that the rule did not fully comply with Sackett and created implementation challenges. The Proposed Rule seeks to address these concerns by clarifying which waters are jurisdictional, redefining key terms, and expanding certain exclusions.

Key Changes in the Proposed Rule

1. Federal Jurisdiction Focuses on Relatively Permanent Waters

Under the Proposed Rule, WOTUS would include only:

• Traditional navigable waters (TNW) and the territorial seas;
• Most impoundments of WOTUS;
• Relatively permanent tributaries (RPT) of TNW, the territorial seas, and impoundments;
• Wetlands with a continuous surface connection to TNW, RPT, or impoundments; and
• Lakes and ponds with a continuous connection to TNW or RPT.

Key definitions:

• Relatively Permanent: Waters that stand or flow year-round or at least during the wet season.[5] Intermittent flow or seasonal flows outside the wet season do not qualify.
• Continuous surface connection: Wetlands must touch (abut) a jurisdictional water and hold surface water at least during the wet season. Only the portions meeting both criteria are jurisdictional.
• Tributaries: Waters with a bed and bank and relatively permanent flow that connect to downstream TNW or the territorial seas, directly or through features that convey relatively permanent flow. Culverts, ditches, berms, or other barriers that do not convey relatively permanent flow generally do not establish jurisdiction.

2. Interstate Waters No Longer Automatically Jurisdictional

The Proposed Rule removes the default federal jurisdiction for interstate waters. Such waters are now jurisdictional only if they meet another WOTUS category (TNW, RPT, or adjacent wetlands).

The Agencies explain that neither Sackett nor prior Supreme Court decisions support federal regulation of all interstate waters regardless of size or connectivity.[6] Non-jurisdictional interstate waters would instead be regulated by States and Tributes under their sovereign authorities.

3. Expanded and Clarified Exclusions

The Proposed Rule clarifies and broadens key exclusions:

• Waste Treatment Systems: All components designed to convey, treat, retain, or remove pollutants—such as lagoons or treatment ponds—remain excluded. This reflects longstanding policy since 1979.
• Ditches: Non-navigable ditches constructed entirely on dry land remain excluded, even if they carry relatively permanent flow. Ditches constructed within wetlands or that relocate a tributary may still be jurisdictional.
• Prior Converted Cropland: Remains excluded unless abandoned (no agricultural use for more than five years with reversion to wetland).
• Groundwater: Explicitly excluded, including groundwater drained through subsurface systems. However, groundwater that surfaces and contributes to a relatively permanent stream may still be jurisdictional.
• Section 404(f) Agricultural Exemptions: Continue to protect many routine farming, ranching, irrigation, and pond construction activities without federal permits.

Practical Implications

The Proposed Rule could substantially reduce permitting burdens and shorten project timelines. Many greenfield and master-planned community developments may no longer require Section 404 permits, and projects that previously triggered compensatory mitigation could proceed without it. Similarly, National Environmental Policy Act (NEPA) reviews—which are often triggered solely by the need for a Section 404 permit—may be avoided. These impacts are likely to be most significant in arid and western states, where ephemeral or intermittent waters would generally fall outside federal jurisdiction.

As federal oversight narrows, state and local authorities are expected to fill the regulatory gap. Approximately half of U.S. states, along with the District of Columbia, already regulate wetlands more broadly than the CWA. States such as Washington and Oregon are considering or implementing state-level dredge-and-fill programs. In these jurisdictions, wetlands lacking a continuous surface connection to a WOTUS may only require state permitting, rather than federal authorization, highlighting the growing importance of state-level compliance.

Conclusion

The Proposed Rule represents a significant shift toward narrowing federal jurisdiction under the CWA, potentially reducing permitting burdens for developers and landowners while increasing reliance on state and local regulation. Stakeholders should consider reviewing the Proposed Rule carefully and may wish to submit comments by the January 5, 2026, deadline. 

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[1] “Updated Definition of ‘Waters of the United States’” 90 Fed. Reg. 52498 (November 20, 2025).

[2] 598 U.S. 651 (2023)

[3] 33 U.S.C. § 1362(7)

[4] “Revised Definition of Waters of the United States’; Conforming” 88 Fed. Reg. 61694 (September 8, 2023).

[5] The term “wet season” would be defined using existing agency tools and, quantitatively, as the period when precipitation exceeds evapotranspiration, with the timing varying by geographic region or ecotype. The Agencies are also seeking public input on alternative approaches that might more accurately define the wet season based on site-specific or regional conditions.

[6] The Agencies reference the 2019 district court decision, which invalidated a prior approach under the 2015 Clean Water Rule, asserting jurisdiction over all interstate waters. That court noted that even small trickles, isolated ponds, or non-navigable waters could fall under federal oversight simply because they crossed a state line. See Georgia v. Wheeler, 418 F. Supp. 3d 1336, 1358-1359 (S.D. Ga. 2019). The Proposed Rule rejects this approach, limiting federal jurisdiction to waters with a clear and direct connection to navigable waters.