EPA Finalizes New WOTUS Rule

By: Joseph Garza


Federal agencies take actions to clarify conflicting legal standards set by the Supreme Court that have divided Circuit Courts for decades. The ongoing legal question regarding the definition of a “Water of the United States” (“WOTUS”) in the context of Clean Water Act (“CWA”) enforcement and implementation may seemingly have been answered. On January 18, 2023, the Environmental Protection Agency (“EPA”) and the Army Corps of Engineers (the “Corps”) announced the finalization of the “Revised Definition of the WOTUS” rule (the “New Rule”).[i] EPA’s hope in promulgating the New Rule is to solve confusion caused by Rapanos v. U.S. The definition of a WOTUS is crucial to CWA practice because it determines the scope of the CWA’s reach. Only a WOTUS will receive the CWA’s protections. It is crucial for all who work with the CWA to have a clear understanding of the definition of WOTUS.

Rapanos v. U.S.

In Rapanos, the Court analyzed whether the definition of a WOTUS under the CWA allowed EPA to regulate a private landowner’s filling of wetlands on their property. These wetlands were adjacent to tributaries that flowed into a navigable WOTUS.[ii] In both the plurality and concurring opinions, the Court issued separate standards defining the scope of the term[iii] “WOTUS:” 1) the Relatively Permanent standard; and 2) the Significant Nexus standard. The Court’s failure to reach a majority opinion in Rapanos left regulators and regulated entities alike without a clear answer as to what waters constitute a WOTUS. The long-awaited answer to this question will determine the CWA’s reach.

The New Rule

The New Rule will reestablish the same categories of waters that previously fell under the scope of a WOTUS, while incorporating both standards set forth in Rapanos by Justice Scalia and Justice Kennedy. These categories of waters will include traditional navigable waters, the territorial seas, interstate waters, and other waters.[iv] The first three categories (“paragraph (a)(1) waters”) have long been accepted as falling under the CWA’s jurisdiction, however the final category is new. “Other waters” include:

[1] impoundments of “waters of the United States” (“paragraph (a)(2) impoundments”); [2] tributaries to traditional navigable waters, the territorial seas, interstate waters, or paragraph (a)(2) impoundments when the tributaries meet either the relatively permanent standard or the significant nexus standard (“jurisdictional tributaries”); [3] wetlands adjacent to paragraph (a)(1) waters; wetlands adjacent to and with a continuous surface connection to relatively permanent paragraph (a)(2) impoundments or to jurisdictional tributaries when the jurisdictional tributaries meet the relatively permanent standard; and wetlands adjacent to paragraph (a)(2) impoundments or jurisdictional tributaries when the wetlands meet the significant nexus standard (“jurisdictional adjacent wetlands”); and [5] intrastate lakes and ponds, streams, or wetlands not identified in paragraphs (a)(1) through (4) that meet either the relatively permanent standard or the significant nexus standard (“paragraph (a)(5) waters”).[v]

Through this language, the New Rule incorporates the WOTUS tests suggested in Rapanos. The Relatively Permanent standard, suggested by Justice Scalia in Rapanos, is satisfied where a water is a “relatively permanent, standing or continuously flowing [body] of water with a continuous surface connection to a traditional navigable water, interstate water, or the territorial seas.”[vi] The Significant Nexus standard, suggested by Justice Kennedy in Rapanos, is satisfied where a water “either alone or in combination with similarly situated waters in the region, significantly affect[s] the chemical, physical, or biological integrity of a traditional navigable water, interstate water, or the territorial seas.”[vii]

Before this New Rule was adopted, some circuits used the Relatively Permanent standard and some followed the Significant Nexus standard. This needlessly complicates the work of regulators, regulated entities, or environmental attorneys. Incorporating both standards will help EPA retain jurisdiction over more waters, while clarifying obligations for all parties involved in the CWA’s complex regulatory scheme. Codifying the Rapanos standards and clarifying the definition of a WOTUS is especially important given both the fact-intensive nature of determining whether a water is a WOTUS and the penalties associated with violating the CWA.[viii]

What is EPA’s Rulemaking Process and where is the New Rule in that Process?

Pursuant to each individual environmental statute, EPA has the authority to develop regulations where it deems necessary. Once EPA deems so, EPA proposes a regulation by listing it in the Federal Register. Members of the public can then comment on the proposed regulation.[ix] EPA will then consider the comments, revise the regulation accordingly, and issue a final rule; the rule will be published in the Federal Register.[x] Finally, EPA will codify the rule in the Code of Federal Regulations (the “C.F.R.”).[xi]

EPA and the Corps responded to public comments and have now published the new WOTUS rule in the Federal register.[xii] The rule will be effective on March 20, 2023.[xiii] Environmental attorneys in Chicago and the remainder of the Midwest must take this time to familiarize themselves with the New Rule or risk costly mistakes in practice.

Implications for the Chicagoland Area

Chicago is home to one of the Midwest’s most diverse wetland habitats. The Calumet Region of southeast Chicago is home to numerous ecological systems, including wetlands and marshes. The region was historically used by humans for industrial purposes but is used by nature as a biologically diverse haven. As industry has left the region, Calumet’s wetlands and marshes have been thought of as an “area with tremendous potential for ecological restoration.”[xiv] The New Rule may directly impact EPA’s ability to regulate certain areas in the region, being that the New Rule is more inclusive of waters as potentially falling under the WOTUS definition.

Marshes and wetlands, such as those found in the Calumet region, exist on the edge of current CWA jurisdiction because wetlands generally are not constantly wet,[xv] though the term “wetland” may suggest otherwise. Due to wetlands not being consistently touched by water, they may not always satisfy the Relatively Permanent standard for a WOTUS, even if they would otherwise satisfy the Significant Nexus standard. Conservationists in the Chicagoland area will be happy to hear that both tests are being codified to increase the chances that wetlands receive CWA protection.


The New WOTUS Rule will go into effect on March 20, 2023. Environmental attorneys, regulators, and regulated entities have little time to plan for the implications. With more waters potentially being protected by the CWA, private landowners should especially consider their CWA obligations. Approximately seventy-five percent (75%) of wetlands are privately owned.[xvi] However, no matter your allegiances, it should be any CWA attorney’s top priority to learn the bounds of CWA jurisdiction as this New Rule adjusts those parameters.


[i] Environmental Protection Agency, Waters of the United States, https://www.epa.gov/wotus.

[ii] Rapanos v. U.S., 547 U.S. 715, 715 (2006).

[iii] See generally Id.

[iv] Revised Definition of “Waters of the United States,” 88 Fed. Reg. 11, (January 18, 2023) (to be codified at 40 C.F.R. pt.120

[v] Id.

[vi] Revised Definition of Waters of the United States, 86 Fed. Reg. 69372, (proposed December 6, 2021) (to be codified at 33 C.F.R. pt. 328).

[vii] Id.

[viii] Kelly v. U.S. E.P.A., 203 F.3d 519, 522 (7th Cir. 2000) (Civil liability under the Clean Water Act is strict and so does not require proof of any mens rea).

[ix] U.S. Environmental Protection Agency, Laws & Regulations, https://www.epa.gov/laws-regulations/basics-regulatory-process.

[x] Id.

[xi] Id.

[xii] Supra note iv at 6.

[xiii] Environmental Protection Agency, Revising the Definition of “Waters of the United States,” https://www.epa.gov/wotus/revising-definition-waters-united-states.

[xiv] The Wetlands Initiative, The Calumet Region, http://www.wetlands-initiative.org/the-calumet-region.

[xv] National Geographic, Wetland Encyclopedic Entry, https://education.nationalgeographic.org/resource/wetland (“A wetland is an area of land that is either covered by water or saturated with water. The water is often groundwater, seeping up from an aquifer or spring. A wetland’s water can also come from a nearby river or lake. Seawater can also create wetlands, especially in coastal areas that experience strong tides. A wetland is entirely covered by water at least part of the year. The depth and duration of this seasonal flooding varies. Wetlands are transition zones. They are neither totally dry land nor totally underwater; they have characteristics of both”).

[xvi] Environmental Protection Agency Office of Water, Office of Wetlands, Oceans, and Watersheds, America’s Wetlands, https://www.epa.gov/sites/default/files/2021-01/documents/wetlands_our_vital_link_between_land_water.pdf