On May 25, 2023, the United States Supreme Court released their highly-anticipated opinion in Sackett v. EPA, U.S. (2023), a lawsuit concerning the scope of wetlands jurisdiction under the Clean Water Act (“CWA”). The decision comes months after the Environmental Protection Agency (“EPA”) released a new definition of the key CWA term “waters of the United States” (“WOTUS”) which determines which waterbodies receive CWA protection. The degree to which wetlands should be protected under the CWA has been a challenge for policymakers since the Act was first passed in 1972. This latest decision from the Court is intended to clarify when wetlands may be considered a water of the United States.


The CWA is the primary federal statute regulating water pollution in the United States. The goal of the Act is to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” 33 U.S.C. § 1251(a). To achieve that goal, the CWA makes it illegal to discharge any pollutant from a discernable, concrete source into “navigable waters” without the appropriate permit. 33 U.S.C. § 1342. Although the traditional legal definition of “navigable waters” refers to those waters that can or may be used to facilitate foreign or interstate commerce, under the CWA “navigable waters” is defined under the CWA as “the waters of the United States, including the territorial seas.” 33 U.S.C. § 1362(7). The term is critical for CWA implementation because only those waters that meet the definition of WOTUS receive CWA protection. Congress chose not to further define the term “waters of the United States,” instead leaving it up to EPA and the United States Corps of Engineers (“the Corps”), the two agencies responsible for administering the CWA, to craft a definition.

Since the time the CWA was first passed, policymakers and courts have struggled to determine what degree of protection wetlands should receive under the Act. While courts have generally agreed that at least some wetlands are included in the definition of WOTUS, the different definitions of that have been promulgated over the years have taken both broad and narrow approaches to wetlands jurisdiction. However, almost every WOTUS definition since 1977 has considered “adjacent wetlands” to be jurisdictional. From 1977 to the present day, most WOTUS definitions have defined “adjacent wetlands” to include those wetlands that are “separated from other waters of the United States by man-made dikes or barriers, natural river berms, beach dunes and the like.” 42 Fed. Reg. 37144; 45 Fed. Reg. 85345; 51 Fed. Reg. 41251; 80 Fed. Reg. 37116; 88 Fed. Reg. 3143-3144.

In 2006, the Supreme Court issued the landmark decision Rapanos v. U.S., 547 U.S. 715 (2006). There, the Court was asked to consider whether CWA jurisdiction extended to wetlands that did not directly “abut” a recognized WOTUS. In other words, the Court considered whether wetlands that were separated from a recognized WOTUS by a natural or man-made barrier fell under CWA jurisdiction. The Court failed to reach a majority opinion, instead producing a four-justice plurality opinion authored by Justice Scalia, and a concurrence authored by Justice Kennedy writing for himself. In the plurality opinion, the justices concluded that the definition of WOTUS should only include those waters that are “relatively permanent, standing, or continuous flowing” such as streams, rivers, and lakes. Then, only those wetlands that shared a continuous surface connection with such waters could fall under CWA jurisdiction. In contrast, Justice Kennedy concluded that wetland jurisdiction should be determined on a case-by-case basis, based on whether the wetland possessed a “significant nexus” to a recognized WOTUS. According to Justice Kennedy, a significant nexus exists when a wetland “either alone or in combination with similarly situated lands in the region, significantly affect[s] the chemical, physical, and biological integrity of other covered waters[.]”

Following the Rapanos decision, courts and EPA tended to apply Justice Kennedy’s significant nexus test either on its own or in conjunction with the plurality opinion. In the years since, different administrations have proposed regulations attempting to further define the term. Most recently, in March 2023, EPA established new regulations adopting both the significant nexus and continuous surface connection tests proposed by the Rapanos plurality. More information on EPA’s 2023 WOTUS rule is available here.

As EPA was in the process of drafting its 2023 rule, the Supreme Court agreed to take up the fifteen-year long dispute, Sackett vs. EPA. The plaintiffs in the case originally filed suit against EPA in 2008, challenging the EPA’s conclusion that they had violated the CWA by backfilling a wetland located on their property. According to EPA, the wetland in question shared a significant nexus with Priest Lake, a WOTUS that was separated from the plaintiffs’ property by a 30-foot road. The plaintiffs disagreed with EPA’s conclusion, arguing that the wetland should not fall under WOTUS jurisdiction because it did not share a surface connection with Priest Lake or any other recognized WOTUS. The Supreme Court heard oral argument in the case in October 2022, where the plaintiffs asked the Court to revisit Rapanos and formally adopt the plurality’s decision. To learn more about the plaintiffs’ arguments and path to the Supreme Court, click here.

On May 25, the Supreme Court returned a decision in favor of the plaintiffs, officially adopting the plurality’s continuous surface water connection test, and overturning Justice Kennedy’s significant nexus approach.

The Court’s Decision

In a 9-0 opinion authored by Justice Alito with five justices joining in the majority and four justices concurring in the outcome, the Supreme Court in Sackett v. EPA held that the use of the word “waters” in “waters of the United States” refers only to geographic features that are “described in ordinary parlance” as streams, oceans, rivers, and lakes, and that only those adjacent wetlands that are “indistinguishable” from such bodies of water due to a “continuous surface connection” fall under CWA jurisdiction. The Court relied on two provisions of the CWA to reach its conclusion.

First, the Court turned to section 1362(7) and focused on the term “waters of the United States” itself. Specifically, the Court examined the word “waters” itself, relying on various dictionaries to conclude that it is commonly understood “waters” refers to “flowing waters” or “bod[ies] of water[s], such as a river, a lake, or an ocean[.]” The Court noted that the plurality in Rapanos relied on the same reasoning to conclude that the word “waters” in “waters of the United States” refers to “streams, oceans, rivers, and lakes.” The Court also agreed with the plurality in Rapanpos that the ordinary meaning of “waters” made it difficult to “reconcile with classifying lands, wet or otherwise, as waters.”

The Court went on to note that limiting the definition of “waters” to open, flowing bodies of water aligned the definition of WOTUS with the term it is defining – “navigable waters.” While courts and policymakers have long acknowledged that CWA jurisdiction extends beyond the traditional navigable waters to which the term “navigable waters” typically refers, previous Supreme Court decisions have clarified that the term “navigable” should not be “read out of the statute.” According to the Court, the CWA’s use of the word “navigable” indicates that the definition of WOTUS “principally refers to bodies of navigable water like rivers, lakes, and oceans.”

After concluding that the “waters” in “waters of the United States” refers to open, flowing bodies of waters like rivers, lakes, and streams, the Court turned to section 1344(g)(1) which Congress added to the CWA in 1977. That provision of the Act allows states to apply to EPA for permission to issue permits for the discharge of dredged or fill material – typically silt, sediment, or soil – into some bodies of water. Specifically, the provision allows states to regulate discharges of dredge and fill material into “waters of the United States,” except for those traditionally navigable waters that can be used to facilitate interstate or foreign commerce, and those “wetlands adjacent thereto.” 33 U.S.C. § 1344(g)(1). Because section 1344(g)(1) specifies that there are some adjacent wetlands which states may not regulate, the Court concluded that therefore some wetlands must fall under the definition of WOTUS.

However, the Court determined that the question of which wetlands may be regulated by the CWA cannot be answered by section 1344(g)(1) alone. Instead, the Court determined that section 1344(g)(1) had to be read in combination with the term “waters of the United States.” According to the Court, the adjacent wetlands referred to in section 1344(g)(1) must be “included” within the definition of “waters of the United States.” Because the Court had already concluded that the use of the word “waters” refers to open, flowing bodies of water, the Court then reasoned that any wetlands included in the definition of WOTUS must be “indistinguishably part of a body water that itself constitutes ‘waters’ under the CWA.” According to the Court, a wetland will be considered “indistinguishable” from a recognized WOTUS if it is “difficult to determine where the ‘water’ ends and the ‘wetland’ begins.” That occurs when a wetland shares a “continuous surface connection” with a recognized WOTUS. Therefore, the Court held that CWA jurisdiction only extends to those wetlands that are “indistinguishable” from a recognized WOTUS due to a continuous surface connection.

The Court’s overall conclusion in Sackett v. EPA is that the definition of WOTUS under the CWA includes open, flowing bodies of water such as streams, rivers, lakes, and the ocean, and those wetlands that share a continuous surface connection with such bodies of water.


While all nine justices joined in the outcome of the Sackett decision, only five justices joined in the majority opinion. Justice Thomas, Justice Kagan, and Justice Kavanaugh each authored concurring opinions.

Although Justice Thomas agreed with the overall outcome of the Sackett opinion, he authored his own opinion to forward his view that the definition of WOTUS should be limited to traditionally navigable waters. According to Justice Thomas, the CWA’s use of the term “navigable waters” throughout its text suggests that Congress intended for CWA jurisdiction to extend only to those waters that could be used as highways of interstate or foreign commerce. To date, no court has fully endorsed this definition of “waters of the United States.”  The concurrences authored by Justices Kagan and Kavanaugh take a broader approach. Both Justices argue that the word “adjacent” means more than just “abutting” or “adjoining.” According to Justices Kagan and Kavanaugh, the definition of “adjacent” includes “neighboring” and “nearby.” While neither Justice would preserve the significant nexus standard authored by Justice Kennedy in Rapanos, both argue that the definition of “adjacent” adopted by the majority in Sackett is more narrow than the usual definition of “adjacent” suggests. Justice Kavanaugh points out that almost since the CWA was first passed, it has been accepted that “adjacent wetlands” include those wetlands that are nearby a recognized WOTUS, but do not share a continuous surface connection due to either a natural or man-made barrier. According to Justice Kavanaugh, the word “adjacent” is broader than the continuous surface connection requirement put forward by the majority. Additionally, Justice Kavanaugh raised questions about where the majority’s opinion leaves wetlands like the ones located along the Mississippi River which would share a continuous surface connection with the river if not for man-made levees installed for flood control purposes. Both Justices Kagan and Kavanaugh would have adopted a broader definition of “adjacent wetlands” than the one outlined by the majority.

Looking Forward                                                                                                

The decision reached by the Supreme Court is at odds with the 2023 WOTUS rule that went into effect earlier this year. While it is still unclear how EPA intends to interpret WOTUS following this ruling, the Court’s decision appears to overrule the portions of the 2023 rule that extend jurisdiction to any bodies of water that are not open, flowing “streams, oceans, rivers and lakes,” and that extend jurisdiction to any wetlands that do not share a continuous surface connection with such bodies of water, including wetlands that are separated from a recognized WOTUS by a natural or man-made barrier. Additionally, the ruling from the Court appears to overturn all of the “significant nexus” language included in the 2023 rule. It is currently unclear how EPA will respond to the ruling, although it is possible that the Agency will initiate another rulemaking to bring the definition of WOTUS inline with the Supreme Court’s decision.

Currently, there are three lawsuits challenging the legality of EPA’s 2023 WOTUS rule. As a result of those lawsuits, the 2023 rule is enjoined in 28 states. Instead of interpreting WOTUS according to the 2023 rule, the states where the rule is enjoined interpret WOTUS according to the pre-2015 regime which includes the 1980s definition of WOTUS, and memoranda from EPA outlining how to determine wetlands jurisdiction post-Rapanos. Along with including guidance on how to implement the significant nexus test, the pre-2015 regime also extends CWA jurisdiction to some wetlands that do not share a continuous surface connection with a recognized WOTUS. It is currently unclear how WOTUS will be interpreted in those states following the Supreme Court’s Sackett decision. More information on the pre-2015 WOTUS regime is available here.

While all three lawsuits are currently on-going, it is unclear how the Sackett decision will impact future litigation. As of May 30, 2023, none of the plaintiffs have asked for a nationwide injunction. At the moment, it appears that all parties are in the process of determining how to proceed.

The National Agricultural Law Center will continue to provide updates on WOTUS as the situation develops.


To read the Supreme Court’s decision in Sackett v. EPA, click here.

To read the text of the 2023 WOTUS rule, click here.

To read the text of the CWA, click here.

For more National Agricultural Law Center resources on the CWA, click here.