Waters of the U.S. Regulations Revised to Follow Supreme Court’s Sackett Decision

September 12, 2023

On 8 September 2023, the United States Environmental Protection Agency (EPA) and the Army Corps of Engineers (the Corps) published a final rule revising the regulatory definition of “waters of the United States” (WOTUS) in response to the Supreme Court’s May 2023 decision in Sackett v. EPA.

Consistent with Sackett, the rule eliminates the “significant nexus test” for all waters and clarifies that wetlands must have a continuous surface connection to WOTUS to qualify for federal Clean Water Act (CWA) jurisdiction.

The rule was not circulated for public notice and comment and became effective immediately upon its publication in the Federal Register. The rule only applies, however, in those states in which the Biden administration’s more expansive WOTUS rule of March 2023 has not been enjoined by the courts. (In the 27 states in which application of the March 2023 rule is enjoined, EPA and the Corps will continue to apply the pre-2015 regulatory regime and the Sackett decision.) As has become tradition, litigation is all but certain to follow.


The CWA prohibits “the discharge of any pollutant” into “navigable waters.” It defines “navigable waters,” somewhat circularly, as “the waters of the United States, including the territorial seas.” The ambiguity of this definition and its importance –the scope of “WOTUS” determines the reach of the CWA – has resulted in multiple regulatory definitions and decades of litigation.

The Supreme Court resolved much, although not all, of the WOTUS debate with its 25 May 2023 decision in Sackett v. EPA. Under the test articulated in Sackett, “waters” include “only those relatively permanent, standing, or continuously flowing bodies of water forming geographical features that are described in ordinary parlance as streams, oceans, rivers, and lakes.” And WOTUS, in turn, are relatively permanent bodies of water connected to traditional interstate navigable waters. By extension, the Court determined that wetlands are not subject to CWA jurisdiction unless they are “as a practical matter indistinguishable from” WOTUS – that is, a wetland must have a continuous surface connection to WOTUS “making it difficult to determine where the water ends and the wetland begins.”

Just months before the Supreme Court handed down its decision in Sackett, the Biden Administration had adopted its own definition, which effectively extended CWA jurisdiction to intrastate lakes, ponds, streams and wetlands that pass either the “relatively permanent” test or the broader “significant nexus” test. Although that rule became effective on 20 March 2023, it had already been enjoined by lower courts in more than half of the United States by the time the Court handed down Sackett. After the Court’s decision in Sackett, EPA and the Corps set out to revise the regulatory WOTUS definition consistent with that decision.

Revised WOTUS Rule

The revised WOTUS definition, published on 8 September 2023, largely follows the Supreme Court’s decision in Sackett. Consistent with that case, the new rule eliminates the “significant nexus” test for both wetland and non-wetland waters. Thus, for example, EPA and Corps regulations will now specify that tributaries to traditional navigable waters, interstate waters, and impoundments thereof are only jurisdictional if the tributaries themselves are “relatively permanent, standing or continuously flowing bodies of water.”

Also consistent with Sackett, the new rule specifies that in order to be jurisdictional, wetlands must have “a continuous surface connection” to WOTUS. The revised WOTUS definition no longer includes a standalone jurisdictional category for interstate wetlands, meaning that in order to qualify for CWA jurisdiction, even wetlands that cross state lines must maintain a continuous surface connection to WOTUS.

The revised WOTUS rule is also notable for what it does not do: most notably, the rule does not attempt to codify what it means for water features to be “relatively permanent, standing or continuously flowing bodies of water.” As discussed below, however, the preamble to the March 2023 WOTUS rule provides lengthy, if often ambiguous, guidance.

Also of note, the revised WOTUS rule does not apply in much of the country. Instead, it went into effect only in the 23 states in which the Biden Administration’s 2023 WOTUS rule remains in effect (including California and most other western states); the revised rule will not be implemented in the 27 states in which courts have already enjoined application of the 2023 WOTUS rule.


The revised WOTUS definition does not break new ground, but instead codifies key holdings in the Supreme Court’s Sackett decision by eliminating the significant nexus test for all waters and clarifying that wetlands must have a continuous surface connection to WOTUS. In this regard, the rule should not prove controversial. Nevertheless, it is likely to face legal challenges, both procedurally and substantively.

Procedurally, the new rule is a bit of an anomaly: the agencies issued it as an immediately effective final rule without prior public notice and comment. The Administrative Procedure Act does allow agencies to issue such rules without prior public notice and comment, but only where an agency for good cause finds that notice and comment procedures are impracticable, unnecessary, or contrary to the public interest; here the agencies claim that public review was unnecessary because the rule merely conforms the 2023 WOTUS rule to Sackett and does not involve the agencies’ exercise of discretion. Opponents of the revised rule are likely to disagree.

Substantively, the courts will inevitably take up questions about the outer reaches of the new definition of “WOTUS.”

One such question is likely to focus on what it means for water features to be “relatively permanent, standing or continuously flowing bodies of water.” As noted above, the preamble to the March 2023 WOTUS rule elaborates on the “relatively permanent” test. But it still leaves much to the discretion of agency staff. For example, the preamble states that streamflow occurring during the monsoon season in the arid west “may be relatively permanent or non-relatively permanent, depending on the conditions at the location.” It goes on to explain that streams that dry within “minutes, hours, or days” of a storm would not meet the “relatively permanent” standard, but streams flowing “for an extended period of time” following “multiple back-to-back storm events” may satisfy that test. The line between these two scenarios is not bright and is likely to be tested in the courts.

The courts likely will also address questions related to the outer bounds of “WOTUS,” such as whether features that flow for an extended period of time following back-to-back storm events qualify as WOTUS.  For example, a desert wash that ordinarily remains dry but that may flow into a traditional navigable water for a few weeks in response to an unusually robust series of storms might satisfy the standard articulated in the March 2023 WOTUS rule preamble. But this result appears in tension with the caselaw. Specifically, the Rapanos plurality opinion on which Sackett so heavily relied emphasized that ephemeral features do not qualify as WOTUS, and although it acknowledged that WOTUS need not flow continually without interruption, the plurality opinion had in mind features that “might dry up in extraordinary circumstances, such as drought” or “seasonal rivers, which contain continuous flow during some months of the year but no flow during dry months,”

In short, the Biden Administration’s revised WOTUS definition makes important revisions to the definition of WOTUS to better bring EPA and Army Corps regulations in line with the Supreme Court’s Sackett decision. We do not expect, however, that it will spell the end to litigation over the scope of “WOTUS” under the Clean Water Act.

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