After much anticipation, the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) have published a proposed rule revising the definition of “waters of the United States” (WOTUS). This proposed rule would narrow the scope of federal jurisdiction over certain waters and wetlands, aiming to provide greater clarity and predictability for federal agencies, states, tribes, landowners, developers, farmers, and industry. The proposed rule is EPA’s second attempt to promulgate regulations in compliance with the Supreme Court’s May 2023 decision in Sackett v. EPA, which significantly altered the federal government’s authority under the Clean Water Act (CWA), as discussed here. In September 2023, the EPA and the Corps issued the 2023 “Conforming” Rule in an attempt to amend the definition of WOTUS consistent with Sackett. Based on concerns raised by stakeholders, largely that the 2023 Conforming Rule was inconsistent with Sackett, the EPA and the Corps have now proposed to again revise the definition of WOTUS.  The rule is not yet final. Public comments on the proposed rule may be submitted between November 11, 2025, and January 5, 2026.

Key Changes

The proposed rule’s revisions limit federal jurisdiction over those waters that are relatively permanent, standing, or continuously flowing—such as streams, oceans, rivers, and lakes—and over wetlands that have a continuous surface connection to and are indistinguishable from such waters. The revised WOTUS definition also clarifies specific waters that are excluded from CWA jurisdiction.

Redefined Jurisdictional Waters

The proposed rule narrows the categories of waters that are considered WOTUS:

• Relatively Permanent Tributaries: The proposed rule defines “relatively permanent” as standing or continuously flowing bodies of water, either year-round or at least during the wet season (the “wet season” is meant to include predictable, extended periods when average monthly precipitation exceeds average monthly evapotranspiration). This means ephemeral streams—those that flow only in direct response to rainfall—would no longer be subject to CWA jurisdiction.

The rule also clarifies that a relatively permanent tributary must have a bed and bank and connect to a downstream jurisdictional water directly or through a water or feature that conveys “relatively permanent flow.” Importantly, if the water is conveyed through a feature like a culvert, dam, or similar artificial feature, or through a wetland or similar natural feature, if the feature does not convey relatively permanent flow, then the tributary is not jurisdictional.

• Adjacent Wetlands Require a Continuous Surface Connection: For a wetland to be jurisdictional, it must have a “continuous surface connection” to a jurisdictional water (a WOTUS). A continuous surface connection only exists if the wetland: (1)physically touches (abuts) a jurisdictional water; and (2)has surface water continuously present at least during the wet season. This eliminates jurisdiction over wetlands that are merely near a jurisdictional water but lack a continuous surface connection to a jurisdictional water. Only the portion of the wetland that has surface water at least during the wet season would be considered “adjacent”; a boundary would be drawn between the jurisdictional and non-jurisdictional portions of the wetland. These revisions are consistent with March 2025 guidance issued by EPA and the Corps clarifying that a “continuous surface connection” cannot be established by a “discrete feature” like a ditch or culvert, because such a feature cuts off the wetland from abutting or touching a jurisdictional water.
• Interstate Waters: The rule removes the standalone category for “interstate waters.” These waters are now only jurisdictional if they independently meet another definition, such as being a traditional navigable water or a relatively permanent tributary. As discussed below, these definitional changes will generally result in less waters being subject to CWA jurisdiction and thereby fewer landowners needing to obtain CWA Section 404 permits for the discharge of dredged or fill material in waters.

New and Revised CWA Exclusions

The proposed rule also clarifies and expands the list of waters explicitly excluded from CWA jurisdiction, providing more certainty for landowners.

• Groundwater: For the first time, the rule explicitly excludes all groundwater from the WOTUS definition, including groundwater drained through subsurface systems like agricultural tile drains. This exclusion is consistent with current practice.
• Ditches: The exclusion for ditches is clarified. Non-navigable ditches excavated entirely in dry land are not jurisdictional. Even ditches that have relatively permanent flow and connect to a jurisdictional water are excluded if they were excavated entirely in dry land. Ditches excavated in wetlands are not excluded.
• Prior Converted Cropland: The rule maintains the longstanding exclusion for prior converted cropland, reverting to a definition that simplifies the process for farmers to confirm this status. The land only loses its excluded status if it is abandoned for agricultural purposes for more than five years and reverts to a wetland that meets the WOTUS definition.
• Waste Treatment Systems: The exclusion for waste treatment systems is clarified with a formal definition, specifying that it includes all components designed to treat wastewater.
• Exemptions under Section 404(f). The rule continues the current regulatory scheme that exempts farmers and ranchers from needing to obtain a Section 404 permit for discharges that occur during the construction and maintenance of irrigation and maintenance of drainage ditches. This allows farmers to engage in routine agricultural operations without a Section 404 permit.

What This Means

The deregulatory nature of the new WOTUS rule is expected to reduce permitting delays, compliance burdens, and costs, particularly for the agricultural, development, energy, and mining sectors. However, the impact will vary depending on the industry and location. The agencies expect that this approach will result in greater reductions in federal jurisdiction in areas where a larger proportion of waters do not flow continuously year-round, such as the arid West. Greater clarification and less uncertainty regarding when wetlands are considered jurisdictional waters will likely save time and costs. With the federal government not regulating as many waters, states and Tribes will likely use their own regulatory authority to fill the gap left by Sackett.

Impacts on Permitting Programs

CWA Section 404: Discharge of Dredged and Fill Material

The agencies anticipate the most significant economic and regulatory impacts will occur within the Section 404 program. The number of required Section 404 permits is expected to decrease significantly because fewer wetlands and ephemeral streams will meet the new jurisdictional tests.

• Time and Cost Savings: A reduction in federal jurisdiction will lead to cost savings for project proponents in the form of avoided permit applications, reduced delays, and decreased demand for compensatory mitigation. Additionally, many projects become subject to the National Environmental Policy Act (NEPA) review due to needing to obtain a Section 404 permit. Projects will forego NEPA review if they do not need a Section 404 permit (unless there is another major federal action related to the project).
• State Law Gap-Filling: The change in jurisdiction may incentivize states to develop their own state-level dredging and filling programs to regulate waters no longer covered federally. Currently, 24 states regulate waters more broadly than the proposed rule, including Washington and Oregon. In these jurisdictions, the regulatory action will likely shift from federal to state jurisdiction rather than disappearing. For example, Washington State has already indicated that it intends to create a state Section 404 permitting program. Read more on this here.
• Impact on Mitigation Banking: The reduction in required federal permits could reduce the demand for mitigation bank credits and ecological restoration services.

CWA Section 402: NPDES Permitting

The impact on the National Pollutant Discharge Elimination System (NPDES) is expected to be more nuanced than Section 404.

• Potential Modifications: Some existing NPDES permits may need modification or termination if the discharge no longer reaches a WOTUS, though widespread permit terminations are not anticipated.
• Continued Liability for Downstream Conveyance: Even if a receiving water (e.g., an ephemeral ditch) is no longer jurisdictional, a point source discharge may still require an NPDES permit if the pollutants are conveyed downstream to a jurisdictional water.

CWA Section 401: State and Tribal Certification

• Less 401 Certifications: Section 401 certification is required for a Section 404 permit to issue. A decrease in Section 404 federal permits will directly result in fewer Section 401 certification requests, reducing the administrative workload for States and authorized Tribes.

Navigating the Path Forward

The EPA and the Corps are currently accepting public comments on the proposal and will hold public meetings to gather stakeholder feedback.

Organizations should consider taking this opportunity to understand how these changes will affect their specific operations. This includes mapping water features on project sites, assessing their potential jurisdictional status under the new definitions, and monitoring state-level responses. Working with environmental consultants and legal professionals can provide the tailored guidance needed to navigate this transition effectively. By proactively adapting to this new framework, businesses can continue to comply with the rules while strategically managing environmental obligations.

We also acknowledge the contributions of Kevin Clancey, Law Clerk, in the development of this update.

This article summarizes aspects of the law and opinions that are solely those of the authors. This article does not constitute legal advice. For legal advice that applies to ‎your situation, you should contact an attorney.