EPA and U.S. Army Corps of Engineers Propose New Definition of “Waters of the United States”

The U.S. Environmental Protection Agency (EPA) and U.S. Army Corps of Engineers (USACE) on Nov. 17 announced a proposed rule adopting a revised definition of “waters of the United States” (WOTUS) under the Clean Water Act (CWA).  The new definition is, in part, an attempt to implement the U.S. Supreme Court’s decision in Sackett v. EPA, 598 U.S. 651 (2023).  That decision, discussed previously by Phelps here, narrowed the Clean Water Act’s reach to only those wetlands that had a continuous surface connection with a relatively permanent body of water. 

The proposed rule is also intended to provide greater regulatory certainty by attempting to clarify what is, and is not, a WOTUS.  The proposed rule is just the latest in a long line of attempts by the agencies to update the regulatory definition of “waters of the United States,” which has been mired in litigation for a decade. 

This is how the proposed rule narrows the reach of the Clean Water Act:

No Longer a WOTUS

Intrastate Lakes and Ponds: Current regulations define intrastate lakes and ponds to be a WOTUS, even where they are disconnected from other jurisdictional waters or would not meet the WOTUS definition independently, i.e. when they are not traditionally navigable waters. The proposed rule would eliminate these “intrastate” lakes and ponds from the definition of WOTUS.

Additional WOTUS Requirements

Relatively Permanent: Under current regulations, “waters of the United States” must be “relatively permanent.”  That limitation was introduced by the plurality opinion in United States v. Rapanos, 547 U.S. 715, 743 (2006), and expressly adopted by the Supreme Court in Sackett, but was never defined in regulations.  In the proposed rule, ‘‘relatively permanent’’ is defined as ‘‘standing or continuously flowing bodies of surface water that are standing or continuously flowing year-round or at least during the wet season.’’ The “wet season” is simply described as “an extended period where there is continuous surface hydrology resulting from predictable seasonal precipitation patterns year after year.”

Continuous surface connection: Currently, for a wetland to be WOTUS, it must have a continuous surface connection to a relatively permanent body of water, such as a creek or pond.  Again, this limitation was introduced by the plurality opinion in Rapanos, and expressly adopted by the Supreme Court in Sackett, but was never defined in regulations.  Under the proposed rule, “continuous surface connection” is defined as “having surface water at least during the wet season and abutting (i.e., touching) a jurisdictional water.”

Tributary: Tributary is not defined under current regulations.  The proposed rule defines tributary, in part, as “a body of water with relatively permanent flow, and a bed and banks, which connect 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.”

WOTUS Exclusions

Waste Treatment System: These are currently excluded from the definition of a WOTUS.  The proposed rule expands on the current definition of waste treatment systems to include lagoons and treatment ponds that are “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).’’  According to the agencies, this change is not meant to change the scope of the waste treatment system exclusion, but to better reflect the agencies’ current practice.

Prior Converted Cropland: These are currently excluded from the definition of a WOTUS. The proposed rule adds to the current definition of prior converted cropland to clarify that the exclusion would no longer apply for Clean Water Act purposes when the cropland “is abandoned,” meaning that it “is not used for, or in support of, agricultural purposes at least once in the immediately preceding five years,” and reverted to wetlands.

Ditch: These are currently excluded from the definition of a WOTUS. The proposed rule redefines ditches to mean “a constructed or excavated channel used to convey water.”  Current regulations state that ditches that “carry a relatively permanent flow of water” may constitute a WOTUS.  The proposed rule eliminates this provision.

Groundwater:  The agencies have never interpreted the term “waters of the United States” to include groundwater, but this was never reflected in federal regulations.  The proposed rule—for the first time—would expressly exclude groundwater, defined to include “groundwater drained through subsurface drainage systems,” from the WOTUS definition.

Takeaways
Keep these issues in mind.

Indirect Discharge: The proposed rule does not appear to address the Supreme Court’s recent decision in County of Maui v. Hawaii Wildlife Fund, 590 U.S. 165 (2020), which was previously discussed by Phelps. There, the Supreme Court held that the CWA’s permitting regime under Section 402 is triggered by both direct discharges into a WOTUS and when there is the “functional equivalent of a direct discharge,” even where the discharge is into groundwater. While the proposed rule expressly excludes groundwater from CWA jurisdiction, it also states in a footnote that the CWA “regulates discharges of pollutants from ‘point sources’ to ‘navigable waters’ whether the pollutants reach jurisdictional waters directly or indirectly.”  Accordingly, EPA and USACE appear to be leaving intact the approach set forth by the Supreme Court in the Maui case.

Narrower CWA Jurisdiction: The proposed rule will narrow what water bodies will be regulated under the CWA.  The agencies published a Regulatory Impact Analysis for the proposed rule. It concludes that fewer wetlands, fewer streams, and fewer lakes and ponds would be regulated under the CWA. This, in turn, will mean that there will be fewer obligations for States and private parties under the CWA. For instance, the proposed rule will mean that fewer waters will be subject to restoration under CWA section 303(d), fewer facilities will have oil spill control measures in the form of Spill Prevention, Control, and Countermeasure (SPCC) plans and Facility Response Plans (FRP), and fewer CWA section 404 permits will be needed for construction projects in streams and wetlands.

Future Litigation: EPA and USACE rules defining WOTUS have been the subject of constant litigation since the Obama Administration proposed its definition in the Clean Water Rule in 2015.  If the proposed rule is finalized, expect environmental groups and some states to immediately challenge the revised definition in federal district court.

Next Steps 
EPA and USACE will now accept public comment on the proposed rule until January 5, 2026, after which they may finalize the rule as proposed or make changes to the rule.  Public comments may be submitted here.

Prior to joining Phelps, Phillip Dupré defended previous EPA and U.S. Army Corps of Engineers rules defining “waters of the United States” in federal district courts throughout the country while at the U.S. Department of Justice.

If you have any questions about the proposed redefinition of “waters of the United States,” please reach out to Steve Levine, Phillip Dupré, Sophie Gray, Blake Donewar or any member of the Phelps Environmental team.