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SCOTUS to Consider Meaning of WOTUS in Upcoming Term

Posted by Jeffrey Karp on 9/28/22 6:42 PM
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By Jeffrey Karp, Senior Counsel, and Edward Mahaffey, Legal Research and Writing Attorney

In its upcoming term, the US Supreme Court will once again consider the definition of “waters of the United States” (WOTUS), a key term in the Clean Water Act (CWA), and its application to wetlands. The case, Sackett v. Environmental Protection Agency, involves a longstanding effort by the Sacketts to build a home on wetlands on their Idaho property without obtaining federal permits. In their second trip to the Supreme Court,[1] the Sacketts have challenged the current definition of WOTUS, seeking to exclude wetlands without a continuous surface water connection to a body of water that is itself considered WOTUS. As the Court’s decision may narrow the WOTUS definition by removing certain wetlands and bodies of water currently subject to the CWA’s protection, the case has garnered much attention within the environmental community and among Supreme Court followers.

WOTUS in the Clean Water Act

The CWA, enacted by Congress in 1972, establishes a program of water pollution regulation to protect navigable waters, which the CWA defines as “waters of the United States.” A core provision of the CWA is the prohibition of the unauthorized “discharge of any pollutant,”[2] including “any addition of any pollutant to navigable waters from any point source.”[3] Other CWA provisions also rely on the concept of “navigable waters,” such as a requirement that states report biennially on the water quality of those waters,[4] and provisions mandating certain state-level planning requirements.[5] The term effectively establishes the boundaries of the authority granted to EPA and the Army Corps of Engineers (Corps) under the CWA.

The CWA does, not, however, appear to use the term “navigable waters” in one of its ordinary senses, such as “deep enough and wide enough to afford passage to ships.”[6] Instead, it defines it as “the waters of the United States, including the territorial seas,”[7] a rather ambiguous term that seems to imply something broader than literally navigable bodies of water. It is the long-standing dispute concerning the regulatory definitions of WOTUS that underlies the current challenge.

Early History of the Regulations

The Corps issued its first definition of WOTUS in 1974.[8] In response to a federal district court decision requiring the Corps to adopt a broader definition,[9] the Corps issued a new definition of “navigable waters,” or WOTUS, in 1975, which included “[a]ll coastal wetlands, mudflats, swamps, and similar areas that are contiguous or adjacent to other navigable waters” and “[f]reshwater wetlands including marshes, shallows, swamps and, similar areas that are contiguous or adjacent to other navigable waters and that support freshwater vegetation.”[10]

Congress amended the CWA in 1977, but the definition of “navigable waters” as WOTUS remained intact. In 1986, EPA and the Corps adopted new regulations under the CWA, including revised definitions of WOTUS, which were similar between the two agencies. The definition of WOTUS remained relatively stable from 1986 until 2015.

As of 2008, when the Sacketts filed their first complaint, WOTUS included “[a]ll waters which are currently used, or were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters which are subject to the ebb and flow of the tide” and “[a]ll interstate waters including interstate wetlands,” and the territorial seas, but it also included various kinds of intrastate waters. The logic of including these intrastate waters was rooted in the Commerce Clause: “All other waters…the use, degradation or destruction of which could affect interstate or foreign commerce,” were included, such as those that “are or could be used by interstate or foreign travelers for recreational or other purposes,” that contain “fish or shellfish” that “are or could be taken and sold in interstate or foreign commerce,” or that “are used or could be used for industrial purposes by industries in interstate commerce.” Also included were impoundments of other WOTUS, tributaries of the other types of waters included so far (except for tributaries of the territorial seas), and finally, “wetlands adjacent to waters (other than waters that are themselves wetlands) identified” in the prior parts of the definition. The definition excluded “prior converted cropland,” however.[11]

Precedents: Three Previous Supreme Court Cases on WOTUS

The US Supreme Court previously has decided three major cases involving the definition of WOTUS: United States v. Riverside Bayview Homes, Inc.,[12] Solid Waste Agency of Northern Cook County v. Army Corps of Engineers (SWANCC),[13] and United States v. Rapanos.[14]

In Riverside Bayview, the Court considered whether the Clean Water Act and the regulations promulgated thereunder authorized the Corps “to require landowners to obtain permits from the Corps before discharging fill material into wetlands adjacent to navigable bodies of water and their tributaries.”[15] The Court applied “Chevron deference,” judicial deference to reasonable agency interpretations of ambiguous laws they implement,[16] and ruled in favor of the Corps. The Court acknowledged that “On a purely linguistic level, it may appear unreasonable to classify ‘lands,’ wet or otherwise, as ‘waters,’” but pointed out that “the transition from water to solid ground is not necessarily or even typically an abrupt one.”[17] In view of “the legislative history and underlying policies” of the CWA, including “a broad, systemic view of the goal of maintaining and improving water quality,” the Court held that “the Corps’ approach of defining adjacent wetlands as ‘waters’ within the meaning of § 404(a)” was reasonable.[18]

The Court again addressed the definition of WOTUS in SWANCC, a case in which the Court rejected the Corps’ attempt in the context of the Migratory Bird Rule to expand WOTUS’s scope to regulate intrastate waters because these waters might be used by migratory birds.[19]

The Court did not apply Chevron deference in assessing the Migratory Bird Rule’s validity, because it was unclear whether the rule was within the scope of Congressional authority under the Commerce Clause.[20] However, the Court did not rule on the constitutional issue; rather, it found the Rule was not authorized by the CWA because it was too far removed from the concept of “navigable waters”: “We said in Riverside Bayview Homes that the word ‘navigable’ in the statute was of ‘limited import,’…But it is one thing to give a word limited effect and quite another to give it no effect whatever.”[21] According to the Court in SWANCC, “[i]t was the significant nexus between the wetlands and ‘navigable waters’ that informed our reading of the CWA in Riverside Bayview Homes.”[22]

Finally, the fractured decision in Rapanos, which the Court will reconsider in Sackett, further complicated the definition of WOTUS by failing to reach a clear consensus on the government’s regulatory authority. Justice Scalia’s plurality opinion was joined by Chief Justice Roberts and Justices Alito and Thomas; Justice Stevens’ dissent was joined by Justices Souter, Ginsberg, and Breyer; and Justice Kennedy, concurring in the judgment to vacate and remand the Sixth Circuit’s ruling for the government, wrote only for himself. Chief Justice Roberts also wrote a separate concurrence, while Justice Breyer also wrote a separate dissent.

Scalia’s opinion emphasized the word “waters” in “waters of the United States.” Basing his evaluation on a dictionary definition, Justice Scalia found that the WOTUS definition should only include relatively permanent waters. In his view, the “only plausible interpretation” of the phrase ‘the waters of the United States’ includes 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.’”[23] While not rejecting the principle that WOTUS includes adjacent wetlands, Justice Scalia interpreted it narrowly, concluding that “only those wetlands with a continuous surface connection to bodies that are ‘waters of the United States’ in their own right, so that there is no clear demarcation between ‘waters’ and wetlands, are ‘adjacent to’ such waters and covered by the Act.”[24]

Roberts wrote separately to lament that instead of “refining its view of its authority in light of our decision in SWANCC, and providing guidance meriting deference under our generous standards, the Corps chose to adhere to its essentially boundless view of the scope of its power.”[25]

According to Kennedy’s opinion, wetlands that have a “significant nexus” to a navigable waterway qualify as WOTUS.[26] More specifically, Justice Kennedy found that wetlands “come within the statutory phrase ‘navigable waters,’ if the wetlands, either alone or in combination with similarly situated lands in the region, significantly affect the chemical, physical, and biological integrity of other covered waters more readily understood as ‘navigable.’”[27] Thus, Justice Kennedy’s opinion held that wetlands with a significant nexus to an actual navigable (or capable of being made navigable) waterway – to which they had a surface, chemical, or biological connection – were WOTUS.

Stevens would have deferred to the Corps’ interpretation of the CWA by including “wetlands adjacent to tributaries of traditionally navigable waters” in WOTUS.[28] Breyer’s separate dissent took the view that “the authority of the Army Corps of Engineers under the Clean Water Act extends to the limits of congressional power to regulate interstate commerce.”[29

The Rise and Fall of the Clean Water Rule and Navigable Waters Protection Rule

For a few years, EPA and the Corps applied Justice Kennedy’s opinion in Rapanos but did not promulgate a new definition of WOTUS, instead issuing a guidance document in 2008. The agencies eventually concluded, however, that this document, in addition to other guidance they had issued in 2003 in response to SWANCC, “did not provide the public or agency staff with the kind of information needed to ensure timely, consistent, and predictable jurisdictional determinations.”[30] Thus, in 2015, EPA and the Corps promulgated the Clean Water Rule, which included a new definition of WOTUS taking into account the Riverside Bayview, SWANCC, and Rapanos decisions.[31]

The new rule was immediately challenged in court. It was stayed by the Court of Appeals for the Sixth Circuit in 2015,[32] and the stay remained in place until the Supreme Court overturned the stay on jurisdictional grounds in 2018.[33]

Under the Trump administration, the Corps and EPA announced their intention to rescind or revise the Clean Water Rule in 2017,[34] repealed the Clean Water Rule in 2019,[35] and replaced it with the Navigable Waters Protection Rule (NWPR) in 2020.[36] The NWPR protected a significantly smaller set of water bodies than previous rules. In addition to explicitly excluding such categories as “ephemeral features that flow only in direct response to precipitation,” it narrowed the definition of adjacent wetlands.[37] The NWPR was immediately challenged in federal court by environmental groups, and was remanded with vacatur by a federal district court in August 2021.[38] From that point, the WOTUS definition from 1986 would control the agencies’ decision-making.

Meanwhile, EPA and the Corps already were planning to promulgate a new rule protecting more waters than the NWPR, having announced their intent to do so in June 2021.[39] The proposed rule was published in December 2021, with a comment period that ended in February 2022.[40] It notably includes a broad definition of “adjacent”: “Adjacent means bordering, contiguous, or neighboring. Wetlands separated from other waters of the United States by man-made dikes or barriers, natural river berms, beach dunes and the like are ‘adjacent wetlands.’”[41] The final rule has not yet been released.

History of the Sackett Case

In 2007, the Sacketts dumped sand and gravel into wetlands on their property, which are connected to Priest Lake, located 300 feet away, by subsurface water flow.[42] EPA issued an administrative compliance order requiring removal of the sand and gravel.[43] The Sacketts challenged the order in court in 2008, but EPA prevailed, on the grounds of lack of subject-matter jurisdiction, in both the federal district court and the Court of Appeals for the Ninth Circuit.[44] The Sacketts appealed to the Supreme Court, which unanimously held in 2012 that the Sacketts could challenge the compliance order as a final agency action under the Administrative Procedure Act.[45]

On remand, both lower courts ruled for EPA on the merits, with the Ninth Circuit, deciding the case in August 2021, explicitly applying Justice Kennedy’s “significant nexus” test from Rapanos.[46] The Supreme Court granted certiorari in January 2022.[47]

The Upcoming Oral Argument

The Court has agreed to consider whether the US Circuit Court of Appeals for the Ninth Circuit correctly affirmed the agencies’ permitting authority over the Sackett’s property. The oral argument is scheduled for October 3, 2022. The following highlights what we expect to hear from the parties.

The Sacketts’ Position

The Sacketts favor a “two-step framework” for determining whether wetlands are WOTUS, which they will argue should replace the “significant nexus” test.[48] First, “is there a continuous surface-water connection to a ‘water’ such that it is difficult to say where the “water” ends and the wetland begins?”[49] Second, “is the wetland among ‘the waters of the United States’, i.e., subject to Congress’s authority over the channels of commerce?”[50] In other words, under the Sackett’s proposed framework, WOTUS would encompass “traditional navigable waters, as well as intrastate navigable waters over which interstate commerce could pass, plus the nonnavigable wetlands inseparably bound up with such waters—but no more.”[51]

In support of this framework, the Sacketts will contend that Congress’ primary concern in passing the CWA was that EPA and the Corps had construed too narrowly what they could regulate under their existing authorities and enforcement power, not that the agencies’ geographic scope was too circumscribed. Thus, they failed to use existing law to regulate navigable-in-fact waters found entirely within a state.[52]

The Sacketts also will argue that Justice Kennedy’s “significant nexus” test in Rapanos   for determining whether wetlands are WOTUS inadequately constrained EPA, raising the same federalism concerns that played a role in the Court’s rejection of the Migratory Bird Rule in SWANCC.[53]

Among the entities filing amicus briefs in support of the Sacketts were the state of Alaska, 26 other states (led by West Virginia), the US Chamber of Commerce, and the American Petroleum Institute. The 26 states’ brief made many of the same points as the Sacketts’ brief; it also argued against the “significant nexus” test as an encroachment on traditional state authority over “local land and water management.”[54]

EPA’s Position

We expect EPA and other respondents to argue in support of Justice Kennedy’s significant-nexus test in Rapanos. Their brief indicates that they will argue that the 1977 amendments to the CWA acknowledged the breadth of the definition of WOTUS, including adjacent wetlands.[55] Because the Army Corps of Engineers’ regulations had already used the concept of “adjacent” wetlands in their regulations, the amendments imported “the Corps’ specification that a berm or barrier does not defeat adjacency.”[56] Further, the respondents will dispute the petitioners’ constitutional arguments against the significant-nexus test because that test permits jurisdiction over wetlands only if they significantly affect the waters over which Congress has unquestioned Article I authority.”[57]

EPA also will assert support for their position on ecological grounds: wetlands affect “‘the chemical, physical, and biological integrity’ of downstream waters by performing essential water-quality functions.”[58] Moreover, in their view, the Rapanos plurality’s “continuous-surface-connection test” is based on a misreading of Riverside Bayview.[59]

Further, the respondents will defend the significant-nexus test on the grounds that “application of the test reflects the empirical judgments that scientists routinely make” and that the agencies’ experience of applying the test over more than ten years demonstrates its workability.[60]

Amici on EPA’s side included several environmental groups, a duo of former EPA Administrators, a coalition of 17 states and the District of Columbia (led by New York), the state of Colorado, a coalition of Indian tribes, and a coalition of 167 members of Congress

What We Will be Listening for From the Justices

The Justices’ questions during the upcoming oral arguments may provide certain valuable clues to the outcome of the case. Three of the current Justices – Roberts, Thomas, and Alito – joined the plurality in Rapanos, but Chief Justice Roberts also wrote a concurrence in that case, as discussed further below. His questions may provide insight into his current understanding of Rapanos, and how, if at all, his views on WOTUS may have changed.

EPA seeks Chevron deference in the case, which Justice Gorsuch is known to oppose.[61] A key point on which to focus is how the other Justices view Chevron as it applies to this case and more generally. The Corps and EPA seem to believe that they may find support for their view on Chevron deference in Chief Justice Roberts’ concurrence in Rapanos, which they summarize as declaring that “the agency could have ‘avoided’ the result in Rapanos had it responded to the SWANCC decision by identifying additional jurisdictional limitations by regulation.”[62] Thus, the respondents in their brief point out their ongoing “notice-and-comment rulemaking that, among other things, addresses the CWA’s coverage of wetlands and responds to this Court’s decision in Rapanos.”[63]

Observers also should pay particular attention to questions posed by Justices Kavanaugh and Barrett, whose views on the case are perhaps the most uncertain; they are the only two conservative Justices who neither were on the Court at the time Rapanos was decided nor have they expressed the same level of overt opposition to Chevron as Justice Gorsuch.

Further, we will be on the lookout for any discussion of West Virginia v. EPA and the major questions doctrine.[64] The amicus brief of the 167 members of Congress in support of EPA urged the Court not to apply it here. Given the history involving Congress’s amendment of the statute without changing the definition of navigable waters, and the several Supreme Court decisions interpreting WOTUS’s scope, it seems unlikely that the Court would invoke the major questions doctrine here.


The stakes in Sackett are considerable. The definition of WOTUS is essentially the scope of federal jurisdiction and provides the extent of protections afforded under the CWA. Thus, if the Court were to adopt the Sacketts’ continuous-surface-connection test as the definition of WOTUS, a major reduction of environmental protections for wetlands (and for tributaries, if the full “two-step framework” also was adopted) would occur. Also, if in its decision the Court were to narrow the scope of, or outright reject, the further application of Chevron deference, the future evaluation by the courts of environmental cases and administrative law matters generally would be significantly.



[1] In the first Supreme Court Sackett case, the Court ruled that the couple was entitled to pre-enforcement review of an EPA order seeking to stop construction of their house on the Idaho property and seeking statutory penalties for violations of the CWA. Sackett v. Environmental Protection Agency, 566 U.S. 120, 122 and 131 (2012).

[2] 33 USC 1311(a).

[3] 33 USC 1362(12)(A).

[4] 33 USC 1315(b).

[5] 33 USC 1313.


[7] 33 USC 1362(7).

[8] 39 Fed. Reg. 12,115.

[9] NRDC v. Callaway, 392 F. Supp. 685 (D.D.C. 1975).

[10] 40 Fed. Reg. 31,320, 31,324.

[11] 33 CFR 328.3(a) (2008).

[12] 474 U.S. 121 (1985).

[13] 531 U.S. 159 (2001).

[14] 547 U.S. 715 (2006).

[15] Id. at 123.

[16] Id. at 131.

[17] Id. at 132.

[18] Id.

[19] 51 Fed. Reg. 41217.

[20] SWANCC at 173.

[21] Id. at 172.

[22] Id. at 167.

[23] Rapanos at 739.

[24] Id. at 742.

[25] Id. at 758 (Roberts, C.J., concurring).

[26] Id. at 779 (Kennedy, J., concurring in the judgment).

[27] Id. at 780.

[28] Id. at 788 (Stevens, J., dissenting).

[29] Id. at 811 (Breyer, J., dissenting).

[30] 80 Fed. Reg. 37,053 at 37,056.

[31] 80 Fed. Reg. 37,053 at 37,054.

[32] Ohio v. United States Army Corps of Engineers (In re Environmental Protection Agency & Department of Defense Final Rule), 803 F.3d 804 (6th Cir. 2015).

[33] National Association of Manufacturers v. Department of Defense, 138 S. Ct. 617 (2018).

[34] 82 Fed. Reg. 12,532.

[35] 84 Fed. Reg. 56,626.

[36] 85 Fed. Reg. 22,250.

[37] 85 Fed. Reg. 22,250 at 22,340.

[38] Pasqua Yaqui Tribe v. Environmental Protection Agency, 557 F. Supp. 3d 949 (D. Ariz. 2021).


[40] 86 Fed. Reg. 69,373.

[41] Id. at 69,449.

[42] Brief for the Respondents, available at, 8-9.

[43] Id. at 10.

[44] Sackett v. Environmental Protection Agency, 2008 U.S. Dist. LEXIS 60060 (D. Idaho 2008); Sackett v. Environmental Protection Agency, 622 F.3d 1139 (9th Cir. 2010).

[45] Sackett v. Environmental Protection Agency, 566 U.S. 120, 126-27 (2012).

[46] Sackett v. Environmental Protection Agency, 8 F.4th 1075, 1091 (9th Cir. 2021).

[47] Sackett v. Environmental Protection Agency, 2022 U.S. LEXIS 751 (2022).

[48] Petitioners’ Brief on the Merits, available at, 24.

[49] Id. at 25 (capitalization omitted).

[50] Id. at 29 (capitalization omitted).

[51] Id. at 43.

[52] Id. at 38-39.

[53] Id. at 47-48.

[54] Brief of Amici Curiae State of West Virginia and 25 Other States in Support of Petitioners, available at, 7.

[55] Brief for the Respondents, available at, 21.

[56] Id. at 22.

[57] Id. at 38.

[58] Id. at 24, quoting 86 Fed. Reg. at 69,392.

[59] Id. at 25.

[60] Id. at 35-36.

[61] See, e.g., his concurrence in Guedes v. Bureau of Alcohol, Tobacco, Firearms and Explosives, 140 S. Ct. 789, 789-91 (2020).

[62] Brief for the Respondents at 39.

[63] Id.

[64] 597 U.S. ___. We have discussed this case at


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