The Supreme Court Provides Clarity and Contraction on Regulation of Waters of the United States

Client Alert

For the first time in modern history, the scope of federal regulation of wetlands and waters is strikingly clear . . . and narrow. In Sackett v. EPA, the U.S. Supreme Court drew the brightest and most narrow regulatory boundary to date as to which resources are subject to regulation under the federal Clean Water Act (CWA). The ruling removes federal oversight of untold numbers of aquatic resources, especially in the arid West, and effectively guts a controversial Biden administration regulation that became effective in March 2023. As a result, regulation of resources other than traditional oceans, rivers, lakes and streams largely will fall exclusively to states. Further, the ruling has significant implications for developers and other landowners in complying with the federal Endangered Species Act (ESA).

Federal Regulation of Waters of the United States

We have frequently reported on the ever-evolving regulatory definition of waters of the United States (WOTUS), the term encompassing aquatic features subject to regulation under the CWA. The combination of fractured Supreme Court rulings, new proposed definitions of WOTUS with each new presidential administration, and the flurry of lawsuits over any proposed definition have kept the scope of WOTUS muddied and unclear since at least the mid-1980s.

But the most destabilizing legal development was the high court’s fractured rulings in Rapanos v. United States, issued 17 years ago. In Rapanos, no five justices could agree on a rationale to decide the case in which the Environmental Protection Agency (EPA) had asserted jurisdiction over aquatic resources more than 10 miles away from the nearest indisputably jurisdictional navigable waterway. A conservative plurality opinion authored by the late Justice Antonin Scalia held that to be jurisdictional, a feature must have a relatively permanent surface connection to a clearly jurisdictional water. A liberal plurality deferred to the judgment of the federal agencies and would have extended jurisdiction. But a single justice, Anthony Kennedy, rejected both rationales and said that if a resource had a “significant nexus” to the underlying jurisdictional waterbody, CWA jurisdiction could extend to that additional resource.

Soon, notwithstanding that eight justices out of nine had refused to embrace it as the appropriate test of jurisdiction, significant nexus became the foundation for CWA jurisdiction throughout the country. The process of identifying what is and is not a jurisdictional resource—“delineation”—became a very case-specific, fact-intensive and staff-depleting exercise. The Sackett majority notes on more than one occasion that “the agencies later admitted that ‘almost all waters and wetlands across the country theoretically could be subject to a case-specific jurisdictional determination’ under this” significant nexus approach.

The Obama administration attempted to standardize significant nexus variables in definite distances and distribution methodologies to aggregate alleged “similarly situated” resource areas to establish broad swaths of jurisdiction. But the so-called Clean Water Rule was immediately subject to multiple litigation challenges and was eventually withdrawn by the Trump administration. The Trump administration’s effort—the Navigable Waters Protection Rule—was largely patterned off of Scalia’s relatively permanent qualifier from Rapanos but provided for inclusion of more resources than may have passed muster under a strict reading of the Scalia rule. Predictably, the Trump rule also was immediately subject to court challenge and was judicially invalidated before the Biden administration could complete its administrative repeal and replacement of the rule.

In Sackett, the conservative majority of justices (absent Brett Kavanaugh) fully embrace and adopt the Scalia position as the new law of the land as to WOTUS regulation, significantly constraining the reach of CWA authority. Under Sackett, a two-prong test must be satisfied to authorize extension of federal authority:

In sum, we hold that the CWA extends to only those wetlands that are “as a practical matter indistinguishable from waters of the United States.” This requires the party asserting jurisdiction over adjacent wetlands to establish “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.” (Brackets in original.)

Wetlands vs. ‘Other Waters’

The holding above speaks exclusively to wetlands. And the question presented in Sackett for resolution by the Court was limited to the exertion of jurisdiction over wetlands. In fact, Justice Kennedy’s significant nexus analysis and holding in Rapanos similarly were carted exclusively in terms of regulation of wetlands. However, that distinction was quickly dismissed by advocates and the courts, much to the objection of the regulated community. Instead, significant nexus became the test for inclusion or exclusion as WOTUS of any aquatic resource potentially subject to federal regulation.

On one end of the spectrum of potential WOTUS resources, you have the obvious extreme of demonstrably navigable waters such as oceans, rivers, lakes and substantial streams with relatively permanent flowing water. At the other extreme are isolated, sometimes dry features such as prairie potholes, arroyos and vernal pools. In between are tributaries and connective depressions that may only flow intermittently or may be completely dry except when they are carrying rain runoff, so-called ephemeral features. While the Trump rule fully excluded ephemeral features, it left room for some intermittent tributaries to qualify for regulation.

This Sackett ruling appears even more narrow than that Trump rule. Although speaking in terms of regulation of wetlands, the two-part test quoted above would seem to preclude inclusion of all ephemeral features and the vast majority of tributaries. More specifically, under the first prong of the test, a tributary must be “a relatively permanent body of water connected to traditional interstate navigable waters.” “Relatively permanent” eliminates any appreciable level of intermittency of flow, and the requirement to be connected to a traditional interstate navigable water will leave many features with notable flow levels out unless regulators confirm a connection to the requisite underlying jurisdictional feature.

The Biden Administration WOTUS Rule

Spared having to complete a full administrative repeal of the Trump WOTUS rule by a district court judge who invalidated the rule, the Biden administration was in the midst of crafting a new WOTUS definition when the Supreme Court unexpectedly accepted the Sackett saga for review for a second time. And when the oral argument hinted strongly at overstep by EPA in the eyes of a majority of justices, it appears the Biden administration ramped up efforts to publish a new rule in advance of a Supreme Court ruling in Sackett. And it did. The final Biden WOTUS rule relied heavily on well-settled regulations that date back to the Reagan administration. However, it supplemented those well-weathered provisions with additional jurisdictional hooks based on significant nexus principles.

The Supreme Court flatly rejected requests by counsel for EPA that it defer to EPA’s newly issued rule. Noting that agency guidance to field agents directed them to “consider a wide range of open-ended hydrologic and ecological factors,” the Court found EPA’s reliance on significant nexus to be beyond the authority granted by Congress as well as a due process threat to the regulated community given the CWA’s significant civil and criminal penalties. While the Biden WOTUS rule was not directly at issue in Sackett, the Court’s ruling certainly invalidates some of its core provisions, including many of the previously accepted Reagan-era rules.

Endangered Species Regulation

The significant narrowing of the scope of CWA jurisdiction in Sackett will have a profound impact not only on the regulation of waters but also on the implementation of the ESA nationwide. At the risk of oversimplification, landowners that have endangered species or protected habitat on their property now appear to have two, clearer pathways for ensuring federal compliance. The first, “Section 10,” is a lengthy, cumbersome, public and increasingly difficult regulatory labyrinth. It takes time, it is expensive and it is far from certain to make the project viable. A second avenue, “Section 7,” comes into play when the underlying project includes a “federal nexus,” the involvement of a federal action agency with jurisdiction over the project. In the instance of private development activity on private lands, that federal nexus is almost always a permit under the CWA for the partial “fill” of wetlands.

The impact of Sackett is that far fewer aquatic resources nationwide will be subject to federal jurisdiction. With such resources not requiring a permit from a federal agency, they can no longer be a trigger for the less cumbersome, more expedient processing under ESA’s Section 7. Thus, many more development projects will be forced into Section 10 for resolution of any ESA issues. That is of significant consequence for the project in terms of cost, time and risk.


In a one-page concurrence in Rapanos, Chief Justice Roberts chided the federal agencies responsible for implementing the CWA for their failure to promulgate a clear and implementable regulatory definition of WOTUS. After attempting three times to interpret the CWA and rejecting various iterations of WOTUS, the Supreme Court has now opted for clarity and precision. The regulatory line is now remarkably clear. And the scope of federal regulation of aquatic resources is remarkably narrow.



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