The Environmental Protection Agency (“EPA”) and the U.S. Army Corps of Engineers (“USACE”) (together, “Agencies”) have returned with yet another iteration of the definition of “Waters of the United States” (“WOTUS”).
This comes over two years after the Agencies published the Revised Definition of “Waters of the United States” and just months after the U.S. Supreme Court's decision in Sackett v. EPA (“Sackett“) prompted emergency surgery to remove the “significant nexus” test (the “Amended 2023 Rule”). On November 20, 2025, the Agencies released a notice of proposed rulemaking that, if adopted, would again rewrite the scope of federal jurisdiction under the Clean Water Act (“CWA”).
The Amended 2023 Rule primarily deleted the significant nexus framework and narrowed the meaning of ‘adjacent.' This proposal takes a more affirmative step: it attempts to define, in regulatory text, the phrases that now do the most work for determining jurisdiction —”relatively permanent” and “continuous surface connection,” the twin pillars of Sackett‘s jurisdictional standard. Thus, the proposal would codify definitions previously left to preambles, guidance, or case-by-case determinations. The proposed rule is the Agencies' first substantive attempt to rebuild the WOTUS framework after Sackett invalidated the significant nexus standard. It includes the following key provisions:
- Redefines Covered Waters
Under the proposed definition, WOTUS includes: (i) traditional navigable waters and territorial seas; (ii) most impoundments of jurisdictional waters; (iii) relatively permanent tributaries of traditional navigable waters, territorial seas, and covered impoundments; (iv) lakes and ponds (interstate and intrastate) that are relatively permanent and have a continuous surface connection to traditional navigable waters, territorial seas, or covered tributaries; and (iv) adjacent wetlands—but only where wetlands physically abut regulated waters with a continuous surface water connection. The proposed rule removes interstate waters as an independent category if crossing state line is the only jurisdictional feature. If a border-crossing water satisfies the jurisdictional definition of WOTUS on its own, outside of its interstate nature, it is covered.
- Codifies “Relatively Permanent”
Perhaps the most consequential feature of the proposal is the introduction of a regulatory definition of “relatively permanent.” Drawing heavily from Justice Scalia's Rapanos plurality and Justice Alito's Sackett opinion, the Agencies propose to define relatively permanent tributaries, lakes and ponds, and adjacent wetlands as “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season.” This “wet season” formulation includes extended periods of predictable, continuous surface hydrology in the same geographic feature year after year in response to a wet season from predictable seasonal precipitation patterns year after year. It is intended to exclude ephemeral features that flow only in direct response to precipitation events.
While the Agencies emphasize this definition reflects ordinary parlance and Supreme Court guidance, its practical significance cannot be overstated. Whether a stream, ditch, or tributary meets the “relatively permanent” threshold will often determine whether downstream features—particularly wetlands and ponds—can ever qualify as jurisdictional. In effect, the proposal hard codes a hydrologic durability test into the definition of WOTUS, shifting the jurisdictional inquiry away from ecological function and toward observable surface flow.
- Defines “Continuous Surface Connection”
The proposal also introduces a regulatory definition of “continuous surface connection.” Under the proposed text, a continuous surface connection exists only where a wetland, lake, or pond physically abuts jurisdictional water and has surface water connecting it to that water at least during the wet season. Subsurface hydrology, periodic sheet flow, or separation by berms, roads, or dunes is not enough.
This definition reflects the Sackett Court's insistence that jurisdictional wetlands be “indistinguishable” from traditional navigable waters. At the same time, it marks a sharp departure from decades of agency practice that treated adjacency—rather than direct surface abutment—as the touchstone of wetland jurisdiction. Wetlands separated from jurisdictional waters by even narrow barriers may remain outside federal jurisdiction under this approach, regardless of their flood storage, water quality, or habitat value.
- Redefines Tributaries
The Agencies propose revisions to several other key terms that often arise in jurisdictional determinations. Significantly, a “tributary” is defined as a body of water with relatively permanent flow and a bed and bank that connects to a downstream traditional navigable water or the territorial seas, either directly or through one or more waters or features that convey relatively permanent flow. These can include natural, man-altered, and man-made waterbodies, such as rivers, streams, ditches, canals, lakes, ponds, and impoundments, so long as these waters meet the proposed definition of “tributary.”
Tributaries can connect directly to traditional navigable waters or the territorial seas, or they may connect through other jurisdictional tributaries, adjacent wetlands that convey relatively permanent flow, certain jurisdictional impoundments, or jurisdictional lakes and ponds. This definition effectively removes intermittent and ephemeral channels from the tributary category.
- Expands and Clarifies Exclusions
In addition to definitional changes, the proposal reorganizes and clarifies several exclusions. Ditches constructed or excavated entirely in dry land are not WOTUS. However, ditches can be jurisdictional if navigable, like a canal. The proposal explicitly excludes from the definition of WOTUS groundwater and features that convey water exclusively through subsurface flow. The proposed rule reaffirms the waste treatment system exclusion, underscoring that treatment ponds and lagoons constructed for wastewater purposes remain outside CWA jurisdiction. The proposal also revisits the exclusion for prior converted cropland, aligning it more closely with USDA determinations and agricultural practice.
Collectively, these exclusions reinforce the Agencies' intent to limit federal jurisdiction to surface waters that are readily identifiable as waters in the ordinary sense, leaving regulation of many borderline or functionally important features to the states.
- Requests Public Input
The Agencies repeatedly acknowledged that the proposed definitions raise implementation challenges and expressly solicited comment on several issues through January 5, 2026. Among the most significant requests for input were:
How to determine whether water is “relatively permanent” in regions with highly variable precipitation or prolonged drought;
Whether the “wet season” concept is sufficiently clear and administrable across different climatic regions;
How to evaluate continuous surface connections where surface water is present predictably but only intermittently; and
Whether more examples or exclusions are needed to address artificial features, legacy agricultural drainage, or stormwater conveyances.
These questions signal that, while the Agencies view the proposal as faithful to Sackett, they recognize that bright-line definitions may produce hard cases in the field—particularly in arid regions, coastal plain landscapes, and heavily managed watersheds.
Implications for States and Regulated Parties
For states like North Carolina, which have tethered their wetland definitions to the federal WOTUS framework, the proposed rule reinforces the post-Sackett reality: many wetlands and headwater features will remain outside federal jurisdiction unless states act independently. Lawmakers who supported the 2023 NC Farm Act (S.L. 2023-63) as a limit on state authority relative to a federal definition that included the significant nexus test may have experienced buyer's remorse in that Sackett and resulting WOTUS definitions dramatically reduced protections under the same statutory provision. Wetlands that previously required both a CWA Section 404 Permit and a Section 401 State Certification may now fall entirely outside regulatory protection. For rapidly developing regions or storm-vulnerable coastal counties, this could accelerate conversion and fill without mitigation requirements. The proposed rule does not—and cannot—prevent states from regulating beyond federal minimums, but state-level legislative action will be necessary to restore historical regulatory coverage.
From a compliance perspective, uncertainty is not gone, only refocused. For landowners and developers, the proposal promises greater predictability but also places increased importance on jurisdictional determinations. Landowners must continue to assess jurisdictional features early in project design. While ephemeral features are not jurisdictional under the new framework, reliance on that expectation without a jurisdictional determination remains risky. Preliminary jurisdictional determinations may regain value as a planning tool, letting landowners move forward while reserving flexibility.
Watching and Waiting in 2026
Whether the proposed rule ultimately brings stability to WOTUS—or merely marks another waypoint in a long regulatory pendulum swing—will depend on how the final definitions are refined and whether they withstand judicial scrutiny. The Agencies are now trying to lock Sackett into regulatory text, shifting the debate from judicial interpretation to administrative line-drawing, where the consequences will be felt most acutely on the ground. After five versions of WOTUS in 10 years, much of the regulated public is over the whiplash and has acclimated to the metronome effect of a pendulum swinging between administrations. Rather than dwelling on the volatility of WOTUS policy, regulated entities can treat this moment as an opportunity to partner with professional environmental legal and consulting advisors to understand the evolving contours of federal oversight. As with every definitional shift in this space, preparation and collaboration is key to navigating the next phase of CWA implementation.
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