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The Latest on Defining WOTUS: Is it All about Adjacency?

Laura Diane Heusel


  • Reviews the 2007 Sackett I case with the 2022 Sackett II case.
  • Compares Sackett to the case Rapanos v. Environmental Protection Agency.
  • Addresses how the meaning of “adjacent” took center stage in the Sackett argument but left no clear indication as to how the Court would reconcile the question of adjacency.
The Latest on Defining WOTUS: Is it All about Adjacency?
George Pachantouris via Getty Images

Environmental lawyers were treated to a spirited argument regarding the scope of federal regulation of waters of the United States (WOTUS) at the start of the new Supreme Court term. The occasion was the oral argument in Sackett v. Environmental Protection Agency on the issue of whether the U.S. Court of Appeals for the Ninth Circuit set forth the proper test for determining whether wetlands are WOTUS under the Clean Water Act (CWA), 33 U.S.C. § 1362(7). The Ninth Circuit set the stage by applying Justice Kennedy’s “significant nexus” test from Rapanos to the Sackett’s property. Rapanos v. United States, 547 U.S. 715 (2006). Universally applying the significant nexus test would broaden the Corps’ interpretation of WOTUS and would require CWA permits for development on wetlands, even if those wetlands do not meet Justice Scalia’s test from Rapanos, requiring a “continuous surface connection” to other WOTUS.

The Sackett Cases and the Sackett II Oral Argument

The recent oral argument is the Sacketts’ second trip to the Court. The case began in 2007, when the Sacketts purchased property near Priest Lake, a navigable water in Idaho, and sought to build a home. Soon after the Sacketts began work, the Environmental Protection Agency (EPA) issued an administrative order, requiring the Sacketts to restore their property to its natural state or face CWA penalties. The Sacketts took their response to court, claiming that EPA’s order was illegal since their property was not a WOTUS subject to the CWA. In the first case (Sackett I), the Court held that the Sacketts were legally entitled to challenge EPA’s administrative order as a final agency action. On remand, the Ninth Circuit turned to the substantive issue of whether the Sackett’s property contained regulated wetlands (Sackett II). The Ninth Circuit ruled in favor of EPA, holding that the wetlands on the Sackett’s property were “adjacent” to a jurisdictional tributary and applying the “significant nexus” to determine that the property had a significant nexus to Priest Lake making it regulable under the CWA. The Sacketts appealed, arguing that the significant nexus test was too broad and asking the Court to limit regulatory authority to wetlands with a “continuous surface connection” to navigable waters.

The Sacketts’ appeal made its way the to the Supreme Court, setting the stage for a high-stakes argument on October 3, 2022. After brief remarks by counsel for the Sacketts, the justices zeroed in on CWA section 404(g), which authorizes states to assume, with the Corps’ permission, responsibility for dredge-and-fill permitting for navigable waters, “including wetlands adjacent thereto.” Section 404(g) is part of the 1977 CWA amendments which authorized the Corps permitting program for the discharge of dredge and fill material to WOTUS and the “wetlands adjacent thereto.” The Sacketts believe that EPA should require that a wetland “abut”—not merely be adjacent to—and also be indistinguishable from a WOTUS in order to be subject to regulation. In other words, adjacency alone is not enough.

Early in the argument, Justice Thomas remarked that as to “adjacent . . . I’m done with that word.” Despite his sentiment, questioning as to what Congress meant by “adjacent” dominated the questioning. Justices wondered whether “adjacent” is limited to waters that physically touch each other or are separated by greater distance. Questioning, for example, whether wetlands separated from the Mississippi River by berms should come within the reach of the CWA. As the argument went on, even “conservative” justices seemed reluctant to limit the bounds of adjacency.

Justice Kagan noted that “things can be adjacent to each other without touching each other,” such as the New York apartment building where she grew up: “If I say there are two adjacent apartment buildings, do they have to be touching each other?” Justice Roberts added that one would “readily say that a train station is adjacent to the tracks even though it’s not touching the tracks.” Justice Kavanaugh added that EPA considers wetlands “adjacent” even if a berm or dike separates them from a WOTUS. Justice Jackson wondered why Congress did not say “immediately adjacent” or “abutting” if it meant to limit the scope of the Corps’ power to regulate adjacent wetlands.

Several of the justices quizzed counsel on both sides as to whether the word “adjacent” requires actual touching or is more akin to neighboring; and, whether this meaning dictates the decision to regulate when wetlands have either a “significant nexus” (Justice Kennedy’s test from Rapanos) or a “continuous surface connection” (Justice Scalia’s test from Rapanos) to WOTUS. Later, several of the justices seemed to agree that the test for a “significant nexus” is separate and apart from adjacency. To which Justice Gorsuch asked EPA’s attorney: how does the agency define “adjacency” independently of “significant nexus.” EPA’s counsel’s answer was unclear. Justice Sotomayor asked whether there was another test aside from adjacency and the tests from Rapanos, to which the Sacketts’ counsel indicated “no.”

Then and Now—Sackett II versus Rapanos

Prior to Sackett II, Rapanos v. Environmental Protection Agency was the last blockbuster WOTUS case decided in 2006. Rapanos considered whether Congress intended to regulate discharge to a wetland situated adjacent to a non-navigable, manmade ditch connected to Auvance Creek (a navigable water) thence to Lake St. Clair in Michigan. From the petitioner’s perspective, the issue in this case was whether CWA section 404(a) conferred jurisdiction “over the entire tributary system, from the smallest trickle to the largest wetland . . . sweeping in remote, non-navigable wetlands 20 miles from the traditional navigable water.”

The oral argument that ensued in Rapanos was, in some respects, like the recent argument in Sackett II, making me question whether we are any closer now to settling on a definition of WOTUS than we were then.

We pulled up the transcript from the Rapanos argument to confirm. There, Justice Souter opened a line of questioning related to the proximity of impacted navigable waters to the source of pollutants, asking whether the developer’s interpretation would “allow[] an end run around the regulation . . . . All you’ve got to do is dump the pollutant further—far enough upstream in the watershed and you get away scot-free.”

Later in the argument, after a discussion on the berms located on the property in question, Justice Ginsburg posed a hypothetical that seemed to run through Sackett II as well: “If this berm were next to a wetland that would otherwise be adjacent to a river . . . is it the berm that prevents there being a hydrological connection?” In response to questioning from Justice Roberts as to whether “one drop” constitutes a hydrological connection, counsel for EPA argued that adjacency implies a hydrological connection regardless of whether a connection of “one drop” can be shown.

In the final minutes of the Rapanos argument, Justice Scalia asked counsel for the petitioners to “tell us what you make of section 404(g).” The essence of counsel’s answer was that section 404(g)’s “adjacency” did not matter nearly as much as the existence of a hydrological connection. In practice since the Rapanos decision, that same logic seems to control in CWA discharge litigation.

What’s Next?

We would be amiss to guess how the Court will rule in Sackett II. Despite speculation that outcome in Sackett II would adopt the “significant nexus” test, the argument left us uncertain. The meaning of “adjacent” took center stage in the argument but left no clear indication as to how the Court would reconcile the question of adjacency in concert with the choice between the “significant nexus” and “continuous surface connection” tests. It seems that we are quite good at deciding whether to regulate in the extremes—we all agree on whether to regulate a wetland that abuts a WOTUS or a wetland that is 20 miles away from a WOTUS. Ironically, it is the middle ground where practitioners and courts have trouble agreeing on “middle ground.”

Both Rapanos and Sackett II involved unique factual circumstances for the wetlands in question: the Rapanos wetland separated by a man-made ditch distant from the nearest navigable water, and the Sackett II wetland with no continuous surface connection to Priest Lake. Regardless, like Rapanos has since it was decided in 2006, the outcome of Sackett II will have implications to many wetlands in many positions, whether adjacent or not.