EPA and Army Corps Propose to Narrow Federal Jurisdiction Under the Clean Water Act

On Monday, November 17, 2025, the U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers (Corps) (collectively, the “Agencies”) released a pre-publication proposed rule to revise the definition of “Waters of the United States” (WOTUS) under the Clean Water Act (CWA).  The proposal responds to the U.S. Supreme Court’s 2023 decision in Sackett v. EPA, 598 U.S. 651 (2023), but goes further than the Biden Administration’s response to the Sackett ruling in August 2023 (the “Conforming Rule”).[1]  Sidley’s blog post on the prior administration’s rule can be found here.

If finalized, the rule would further narrow federal jurisdiction after Sackett, especially over tributaries, wetlands, ditches, lakes, and ponds that lack direct and relatively permanent surface connections to traditional navigable waters.  Indeed, the proposal predicts that there will be substantially fewer federal jurisdictional determinations, as well as fewer permits under CWA Section 404 permits.  Here are some key takeaways from the proposal:

• Removal of “interstate waters” as an independent basis of jurisdiction. Waters crossing state lines were historically considered to be jurisdictional waters.  The proposal would eliminate that independent jurisdictional basis.  Instead, interstate waters would qualify only if they meet another category, such as a relatively permanent tributary or lake/pond with a continuous surface connection.  As such, some rivers, streams, and wetlands historically regulated solely because they cross state boundaries may no longer require federal permits.
• An explicit regulatory definition of “relatively permanent” waters. Until now, this phrase has not been defined by regulation.  Under the proposal, a water is “relatively permanent” if it has standing or continuously flowing surface water year-round or at least throughout the region’s “wet season.”  Ephemeral waters — flowing only after precipitation — are categorically excluded, while intermittent waters would qualify only if they remain wet through the entire wet season, not just episodically.  The “wet season” would be determined using various available tools, imagery, and climate data.
• Narrowed definition of “tributary.” The Biden administration’s Conforming Rule had retained a relatively broad conception, maintaining a tributary contributes flow to a traditionally regulated water.  Under this proposal, a tributary must: (i) have a bed and banks, (ii) have a relatively permanent flow, and (iii) maintain a direct or indirect surface connection through other relatively permanent waters to a traditional navigable water.  However, if any segment in the connection has ephemeral or non-relatively permanent features (e.g., dry wash, roadside ditch, isolated wetland), then jurisdiction would be eliminated.
• A strict “continuous surface connection” would be required for wetlands to be subject to federal jurisdiction. Again, the proposal would go further than the 2023 Conforming Rule, as there the agencies aligned the regulatory text with the Sackett requirement for a continuous surface connection but retained some flexibility.  This proposal would adopt a stricter two-part test for adjacent wetlands: (i) the wetlands must physically touch (i.e., “abut”) a jurisdictional water, and (ii) they must have surface water present at the point of contact during the “wet season.”  Further, the agencies propose to specify that roads, berms, levees, and similar barriers typically sever jurisdiction, unless surface water still reaches across or through them during the wet season.
• Lakes and ponds remain a category but narrowed. The proposal would retain these as a separate category but would be jurisdictional only if they are: (i) relatively permanent, and (ii) continuously surface-connected to WOTUS.  The agencies also solicit comment on whether to eliminate this category entirely and treat lakes/ponds only as tributaries if they meet that definition.
• Exclusions and carve outs are retained but clarified and expanded.
  • Waste Treatment Systems. The proposal would codify a more detailed definition, clarifying that waste treatment systems include lagoons, settling basins, cooling ponds, and related structures designed and operated to treat wastewater.  Abandoned systems, however, may lose the exclusion.
  • Prior-Converted Cropland. The proposal would retain the exclusion, while also emphasizing the abandonment test (five years without agricultural use and reversion to wetlands).  The agencies provide broader examples of qualifying agricultural uses, including grazing and conservation program enrollment.
  • Ditches. Whereas the Conforming Rule treated ditches largely on a case-by-case analysis, the proposal would create a more robust exclusion.  Ditches excavated entirely in dry land would be excluded, including many roadside and agricultural ditches — unless they meet the definition of a tributary.  Ditches constructed in or relocating a stream or wetland would not qualify for the exclusion.
  • Groundwater. For the first time, the agencies are proposing to expressly exclude groundwater, reinforcing the surface-water focus and clarifying that subsurface flow pathways do not establish federal jurisdiction as WOTUS.
• If finalized, regulated sectors could see material changes.
  • Development and construction. Fewer onsite wetlands and channels would qualify as federally regulated waters, reducing federal permitting and associated mitigation.  Linear projects (such as pipelines, highways, and transmission corridors) might see significant reductions in required CWA Section 404 permits.  However, state and tribal authority remains in place, and they could take a more active role.
  • Energy and infrastructure. Projects affecting seasonal washes or intermittent tributaries could avoid federal review, while fewer jurisdictional wetlands behind levees or embankments could reduce delays and mitigation costs.
  • Agriculture and forestry. Reinforced exclusions and broad ditch exclusions may offer opportunities for simplified farmland management.  At the same time, owners should remain attentive to the abandonment test, which is now clearer and more enforceable.
  • Industry and manufacturing. Facilities relying on containment ponds, cooling ponds, or other waste treatment structures could see benefits from clarified exclusions.  Moreover, the proposed groundwater exclusion may reduce enforcement risk for subsurface releases based on releases to waters of the United States, although liability under other CWA provisions and laws are not affected.

EPA will accept public comments for 45 days following publication in the Federal Register.

[1] See 88 Fed. Reg. 61,964 (Sept. 8, 2023).

This post is as of the posting date stated above. Sidley Austin LLP assumes no duty to update this post or post about any subsequent developments having a bearing on this post.