On November 17, 2025, the U.S. Environmental Protection Agency (EPA) and the Army Corps of Engineers (the Corps) announced a proposed rule (PR) to revise the definition of “waters of the United States” (WOTUS) by excluding several types of waters from the definition of WOTUS in their respective regulations (40 C.F.R. § 120.2 and 33 C.F.R. § 328.3). This is the sixth proposed change to the WOTUS definition during the past decade. Previous changes to the definition of WOTUS have been the subject of litigation in recent years, and additional litigation challenging these latest proposed revisions may be filed once the proposed rule is finalized. These proposed revisions, if implemented and upheld on appeal, would narrow the applicability of the Clean Water Act. The proposed rule was published in the November 20, 2025 edition of the Federal Register. (Environmental Protection Agency & U.S. Army Corps of Engineers, Definition of “Waters of the United States” (Proposed Rule), 90 FR 52,498 (Nov. 20, 2025)).
The U.S. Supreme Court’s 2023 decision that narrowed the types of water subject to the Clean Water Act in Sackett v. Environmental Protection Agency, 598 U.S. 651 (2023), prompted the most recent iteration of WOTUS. The Court rejected the use of the “significant nexus” test, which had been articulated by Justice Kennedy in his concurring opinion in Rapanos v. United States, 547 U.S. 715 (2006) and advocated by EPA, to reach wetlands purportedly “adjacent to,” even though separated by a road from, the plaintiffs’ property. The Court unanimously concluded EPA’s definition was overbroad, and in a majority opinion by Justice Alito, concluded that Section 404 of the Clean Water Act covers “only wetlands that are as a practical matter indistinguishable from waters of the United States.” Id. at 678. The opinion holds that to regulate wetlands under the Clean Water Act, EPA must show: “first, that the adjacent [body of water constitutes]... ‘water[s] of the United States’ (i.e., a relatively permanent body of water connected to traditional interstate navigable waters); and second, that the wetland has a continuous surface connection with that water, making it difficult to determine where the ‘water’ ends and the ‘wetland’ begins.” Id. at 678–79.
Following the Sackett decision, EPA and the Corps revised their regulations to modify the definition of WOTUS to conform to the Supreme Court’s interpretation. See Revised Definition of “Waters of the United States”; Conforming, 88 Fed. Reg. 61964 (Sept. 8, 2023) (codified at 33 C.F.R. Part 328, 40 C.F.R. Part 120). However, that version of the rule was challenged in litigation and is currently enjoined in 26 states. In those jurisdictions, EPA uses the pre-2015 regulatory regime consistent with Sackett. In the other 24 states, the District of Columbia, and U.S. territories, the Sept. 8, 2023, “Revised Definition” is being implemented.
The proposal by EPA and the Corps is an effort to end the split implementation of the Sackett decision and more “adequately comply” with the Sackett decision’s interpretation of the scope of federal jurisdiction under the Act. The proposal is intended to better effectuate “‘the balance Congress struck between the Clean Water Act section 101(a) statutory objective to ‘restore and maintain the chemical, physical, and biological integrity of the Nation’s waters,’ and the policy in Clean Water Act section 101(b) to ‘recognize, preserve, and protect the primary responsibilities and rights of States to prevent, reduce, and eliminate pollution’ and ‘to plan the development and use . . . of land and water resources.’” 90 FR 52,514 (citing 33 U.S.C. 1251(a) and (b)). This GT Alert summarizes the proposed changes to which waters qualify as WOTUS, which waters do not qualify as WOTUS, and new WOTUS-related defined terms.
Revised WOTUS Definition
EPA and the Corps propose to remove “interstate waters” from the current, five-part definition of WOTUS because the term “can encompass bodies of water that are not relatively permanent, standing, or continuously flowing or that are not themselves connected 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, its removal would ensure consistency with the Sackett decision as well as the Clean Water Act.” The agencies assert the proposed rule would make the rule consistent with Sackett and is needed to “address persistent litigation over this category.” 90 FR 52,516. They also propose to modify the inclusion of “lakes and ponds” to remove the “intrastate” qualifier and to specify that such lakes and ponds must be “relatively permanent, standing or continuously flowing bodies of water with a continuous surface connection to” other waters that qualify as WOTUS. The agencies describe this as a “ministerial change” and speculate that many waters meeting the criteria for (a)5 “lakes and ponds” would also qualify under (a)3 as “tributaries.” 90 FR 52,533.
The proposed rule does not re-incorporate the definitions of “perennial,” “intermittent,” and “ephemeral” waters used in the 2020 Navigable Waters Protection Rule (NWPR) definition of WOTUS promulgated under the first Trump administration (85 Fed. Reg. 22,341 (Apr. 21, 2020). Those terms were used to distinguish between surface waters that, respectively, were defined as “flowing continuously year-round,” “flowing continuously during certain times of the year and more than in direct response to precipitation (e.g. seasonally …),” and “flowing or pooling only in direct response to precipitation (e.g., rain or snow fall),” (id. at 22,338-41), and the NWPR expressly excluded ephemeral waters from the definition of WOTUS. (Id.) Instead, the proposed rule relies on the proposed definition of “relatively permanent,” which encompasses waters that are “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season,” and would thus exclude waters formerly defined as ephemeral without using the previous definition. EPA and the Corps are requesting comments on the proposed definition of “relatively permanent” and its implementation, including on whether it should be limited to perennial waters and whether or how to apply it to waters that flow seasonally (i.e., waters formerly defined as “intermittent”). 90 FR 52,517-21, 52,523-24.
Proposed Changes to Waters that Do Not Qualify as WOTUS
The regulatory definitions of WOTUS define both which waters qualify, and which waters do not qualify despite WOTUS-qualifying features. EPA and the Corps propose the most significant changes to the “non-WOTUS” waters component of their respective definitions, including the following:
- Simplifying “waste treatment systems” to no longer include “treatment ponds or lagoons.”
- Removing the explanation around “prior converted cropland,” instead opting to officially define the term (see below).
- Revising the ditch exclusion to state ditches must be “constructed or excavated entirely in dry land.”
- Explicitly including groundwater, “including groundwater drained through subsurface drainage systems.”
- Continuous surface connection as “having surface water at least during the wet season and abutting (i.e., touching) a jurisdictional water.”
- Ditch as “a constructed or excavated channel used to convey water.”
- Prior converted cropland as “any area that, prior to December 23, 1985, was drained or otherwise manipulated for the purpose, or having the effect, of making production of an agricultural product possible. EPA and the Corps will recognize designations of prior converted cropland made by the Secretary of Agriculture. An area is no longer considered prior converted cropland for purposes of the Clean Water Act when the area is abandoned and has reverted to wetlands, as defined in paragraph (c)(1) of this section. Abandonment occurs when prior converted cropland is not used for, or in support of, agricultural purposes at least once in the immediately preceding five years. For the purposes of the Clean Water Act, the EPA Administrator shall have the final authority to determine whether prior converted cropland has been abandoned.”
- Relatively permanent means “standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season.” According to the EPA and the Corps, this proposed definition takes into account “seasonal and geographic variability by including waters that flow uninterrupted throughout the wetter months.”
- Tributary as “a body of water with relatively permanent flow, and a bed and banks, 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. A tributary does not include a body of water that contributes surface water flow to a downstream jurisdictional water through a feature such as a channelized non-jurisdictional surface water feature, subterranean river, culvert, dam, tunnel, or similar artificial feature, or through a debris pile, boulder field, wetland, or similar natural feature, if such feature does not convey relatively permanent flow. When the tributary is part of a water transfer (as that term is applied under 40 CFR 122.3) currently in operation, the tributary would retain jurisdictional status.”
- Waste treatment system as “all components of a waste treatment system designed to meet the requirements of the Clean Water Act, including lagoons and treatment ponds (such as settling or cooling ponds), designed to either convey or retain, concentrate, settle, reduce, or remove pollutants, either actively or passively, from wastewater prior to discharge (or eliminating any such discharge).”
Proposed New WOTUS-Related Definitions
To further clarify which waters qualify and do not qualify as WOTUS, EPA and the Corps propose to define several terms for the first time:
Next Steps
The rule will be open for public comment until January 5, 2026 (45 days after Federal Register publication). Written comments must reference Docket ID No. EPA-HQ-OW-2025-0322 and may be submitted through Regulations.gov, email, mail, hand delivery, or during one of two hybrid public meetings (dates to be released).
This rulemaking will have important consequences for those who need Clean Water Act permits to disturb jurisdictional waters. Members of potentially regulated industries should carefully evaluate how the proposed changes might affect them and consider submitting comments to inform decision-makers and preserve their rights.