Enforcement and Inspection, Environmental Permitting, Regulatory Developments

A Deep Dive Into the ‘Final’ WOTUS Rule

On January 18, 2023, the long-awaited final “Revised Definition of ‘Waters of the United States (WOTUS)’” rule was published in the Federal Register. It is set to go into effect March 20, 2023. 

The definition of WOTUS is the key to determining the EPA’s authority under the Clean Water Act (CWA).

This final rule repeals the Trump administration’s “Navigable Waters Protection Rule” and largely reverts to the pre-2015 WOTUS definition, with some new guidance and explanation.


The purpose of the CWA, as passed by Congress in 1972, is to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.”  To achieve this goal, the CWA provides the EPA with authority to implement permitting programs that control the discharge of pollutants, fill, and dredge materials into protected waters. Without a permit, the CWA makes it unlawful to discharge any pollutant from a point source into “navigable waters” of the United States.

In the CWA language, Congress broadly defined “navigable waters” as “the waters of the [U.S.], including the territorial seas.”

According to The National Agricultural Law Center, the 1986 definition of WOTUS included seven waterbody categories:

  1. All waters that have been used or could be used in interstate or foreign commerce,
  2. All interstate waters,
  3. All other waters that could affect interstate or foreign commerce if the waters were degraded or destroyed,
  4. The territorial seas,
  5. Impoundments of any waters described in the rule,
  6. Tributaries of any waters described in the rule, or
  7. Wetlands adjacent to any waters described in the rule.

The 1986 definition remained stable until 2015 during the Obama administration.

The Obama administration attempted to define WOTUS by expanding its definition to clarify which bodies of water are automatically covered by the CWA and which must still be dealt with on a case-by-case basis. That rule defined “automatically protected waterways” as any that have a bed, a bank, and a high-water mark, according to Vox. This included many streams that remain dry part of the year.

The Trump administration’s definition made a clear distinction between federally protected wetlands and state-protected wetlands. Its definition of WOTUS pulled “back federal oversight of at least 51 percent of wetlands and 18 percent of streams — many of which had been protected since the Reagan administration,” states an E&E News article.

For many, the Obama administration’s definition was overreaching, and the Trump administration’s definition did too little. Both Obama’s and Trump’s WOTUS definitions were extremely controversial and the subject of multiple court battles.


As with any regulation, there are certain to be legal challenges. To understand what lies ahead, it is important to look at past legal actions and precedent to be better equipped for the future under this new rule.

Three different U.S. Supreme Court (SCOTUS) cases have addressed the definition of WOTUS.

  • In the 1985 United States v. Riverside Bayview Homes, Inc., case, SCOTUS “deferred to the Corps’ assertion of jurisdiction over wetlands actually abutting a traditional navigable water, stating that adjacent wetlands may be regulated as waters of the [U.S.] because they are ‘inseparably bound up’ with navigable waters and ‘in the majority of cases’ have ‘significant effects on water quality and the aquatic ecosystem’ in those waters.”
  • In the 2001 Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers (SWANCC) case, SCOTUS determined that there was no federal jurisdiction “over nonnavigable, isolated, intrastate ponds that lack a sufficient connection to traditional navigable waters. …”
  • In the 2006 Rapanos v. United States case, a four-justice SCOTUS plurality determined WOTUS ‘‘include[ ] only those relatively permanent, standing or continuously flowing bodies of water ‘forming geographic features’ that are described in ordinary parlance as ‘streams[,] … oceans, rivers, [and] lakes,’” and ‘‘wetlands with a continuous surface connection’’ to a ‘‘relatively permanent body of water connected to traditional interstate navigable waters.’’

However, Justice Anthony Kennedy wrote a lone concurring opinion that concluded “to constitute ‘navigable waters’ under the Act, a water or wetland must possess a ‘significant nexus’ to waters that are or were navigable in fact or that could reasonably be so made.”

The term “significant nexus” is defined as waters that form a sufficiently great central link or connection. It’s similar to standing in the middle of a large intersection.

Regarding the above “precedent-setting” cases, instead of following Justice Antonin Scalia’s plurality opinion that narrowly interpreted “navigable waters,” lower courts and the government “uniformly followed Justice Kennedy’s lone opinion, which interpreted the term expansively but very vaguely,” according to Pacific Legal Foundation.

Once again, here is another situation in which analysts say one opinion goes too far and the other is too narrow.

Pending SCOTUS case

Oral arguments in Sackett v. EPA were heard October 3, 2022; it was the first case on SCOTUS’s fall docket. The decision in the Sackett case has been expected to form a legal precedent determining where SCOTUS stands regarding the Rapanos case—with Scalia’s narrow interpretation of “navigable waters” or Kennedy’s broader “significant nexus” test.

The facts of the case are that the Sacketts purchased a small parcel of land on wetlands 100 yards from Priest Lake in Idaho. Their property is separated from the lake by a roadway. When the Sacketts began filling their property to start construction on their home, the EPA stepped in and said they must apply for a Section 404 permit to fill their “wetland” property. They began battling the EPA in court approximately 20 years ago.

Legal counsel for the Sacketts “argue that the roadway relieves them of the need to apply for a Section 404 permit because it severs any physical connection between the wetland and the lake, rendering the wetland non-‘adjacent’ and therefore non-jurisdictional under the test articulated by Justice Antonin Scalia in the court’s 2006 decision in Rapanos v. United States,” Peter Alpert, partner at Ropes & Gray LLP, writes in an opinion article analyzing the Sackett case in Bloomberg Law.

“The EPA argues that the Sacketts’ wetland is jurisdictional under Justice Anthony Kennedy’s opinion in Rapanos, which articulated a broader, ‘nexus’-based test for identifying wetlands that the EPA may regulate for the sake of water quality, and also under regulations through which the EPA and the Corps administered the Section 404 program long before Rapanos was decided,” Alpert says.

During oral arguments in the case, some of the justices focused their questions on the term “adjacency,” with counsel for the Sacketts arguing that in this context, it is defined as “touching,” but Chief Justice John Roberts pointed out that train tracks are adjacent to train stations, yet they do not physically touch one another.

“ … Justice Brett Kavanaugh noted that in the 50 years since the act was passed, the agency has consistently said wetlands and other waters are covered, even when they do not flow into other waters. Near the end of the argument, Justice Kavanaugh wondered whether bringing clarity to the language of the act was the responsibility of Congress rather than the courts,” reported a blog post by The Council of State Governments.

“Most of the justices seemed to be struggling with how to best achieve a balance between protecting U.S. waterways and protecting private property ownership.  Interestingly, the government attorney noted to the justices that the [EPA] was working on a new rule regarding navigable waters and wetlands that would clarify situations like the one at issue in this case.”

The latest ‘final’ WOTUS rule

“This rule establishes a durable definition of [WOTUS] that is grounded in the authority provided by Congress in the [CWA], the best available science, and extensive implementation experience stewarding the nation’s waters,” an EPA news release says. “The rule returns to a reasonable and familiar framework founded on the pre-2015 definition with updates to reflect existing Supreme Court decisions, the latest science, and the agencies’ technical expertise. It establishes limits that appropriately draw the boundary of waters subject to federal protection.”

The rule defines seven categories of waters that fall under CWA authority:

  1. Traditional navigable waters: Large rivers and lakes that could be used in interstate or foreign commerce, as well as water bodies affected by tides.
  2. Territorial seas: Territorial seas that extend 3 miles out to sea from the coast.
  3. Interstate waters: Include waters like streams, lakes, or wetlands that cross or form part of state boundaries.
  4. Impoundments: Impounded bodies of water created in or from WOTUS, like reservoirs and beaver ponds.
  5. Tributaries: Branches of creeks, streams, rivers, lakes, ponds, ditches, and impoundments that ultimately flow into traditional navigable waters, the territorial seas, interstate waters, or impoundments of jurisdictional waters. Tributaries are jurisdictional if they meet either the relatively permanent standard or the significant nexus standard.
  6. Adjacent wetlands: These wetlands can be next to, abutting, or near other jurisdictional waters or behind certain natural or constructed features.  They are most often within a few hundred feet of jurisdictional waters.  Adjacent wetlands are jurisdictional if they meet either the relatively permanent standard or the significant nexus standard or where the wetland is adjacent to a traditional navigable water, the territorial seas, or an interstate water.
  7. Additional waters: These lakes, ponds, streams, or wetlands do not fit into the above categories. They are jurisdictional if they meet either the relatively permanent standard or the significant nexus standard.

It also provides definitions for both “relatively permanent” and “significant nexus”:

  • Relatively permanent is a test that provides important efficiencies and clarity for regulators and the public by readily identifying a subset of waters that will virtually always significantly affect the categories of waters defined above. To meet the relatively permanent standard, the water bodies must be relatively permanent, standing, or continuously flowing waters connected to the categories of waters defined above with a continuous surface connection to such relatively permanent waters or to the categories of waters defined above.
  • Significant nexus is a test that clarifies whether certain water bodies, such as tributaries and wetlands, are subject to the CWA based on their connection to and effect on larger downstream waters that Congress fundamentally sought to protect. A significant nexus exists if the water body (alone or in combination) significantly affects the chemical, physical, or biological integrity of traditional navigable waters, the territorial seas, or interstate waters.

The rule also codifies eight exclusions to WOTUS:

  1. Prior converted cropland, adopting the U.S. Department of Agriculture’s (USDA) definition and generally excluding wetlands that were converted to cropland before December 23, 1985;
  2. Waste treatment systems, including treatment ponds or lagoons that are designed to meet the requirements of the CWA;
  3. Ditches (including roadside ditches) excavated wholly in and draining only dry land and that do not carry a relatively permanent flow of water;
  4. Artificially irrigated areas that would revert to dry land if the irrigation ceased;
  5. Artificial lakes or ponds created by excavating or diking dry land that are used exclusively for such purposes as stock watering, irrigation, settling basins, or rice growing;
  6. Artificial reflecting pools or swimming pools and other small ornamental bodies of water created by excavating or diking dry land;
  7. Waterfilled depressions created in dry land incidental to construction activity and pits excavated in dry land for the purpose of obtaining fill, sand, or gravel unless and until the construction operation is abandoned and the resulting body of water meets the definition of “WOTUS”; and
  8. Swales and erosional features (e.g., gullies or small washes) that are characterized by low-volume, infrequent, or short-duration flow.

Next steps

As with any regulation, future court battles are predicted. In particular, industry analysts foresee challenges regarding the “significant nexus” and “adjacency” tests.

Overall, the final WOTUS rule provides better balance in its scope than either of its predecessors—the Obama administration’s Clean Water Rule and the Trump administration’s Navigable Waters Protection Rule. This rule follows long-standing practices and rules regarding WOTUS by the EPA.

Additionally, with the SCOTUS Sackett ruling still pending, a decision in that case “could abruptly change the legal foundation that underpins the Final Rule and give rise to new legal vulnerabilities,” a K&L Gates LLP Hub blog post notes.

However, some analysts predict that the Sackett decision is unlikely to “strip the EPA of any authority to regulate wetlands until Congress speaks,” Alpert’s opinion articles says.

K&L Gates suggests that the pending Sackett decision may be the reason “the EPA has included in its newest regulatory agenda, released 4 January 2023, plans to propose yet further refinements to the definition of WOTUS as early as November 2023. Through this second rulemaking, the Agencies have indicated that they ‘intend to consider further refinements [to the WOTUS rule] … in light of additional stakeholder engagement and implementation considerations, scientific developments, litigation and environmental justice values.’”

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