On December 30, 2022, the U.S. Environmental Protection Agency (“EPA”) and the U.S. Army Corps of Engineers (“Army Corps”) announced they had finalized the rule establishing the definition of “waters of the United States” (“WOTUS”) under the Clean Water Act (“CWA”) (the “WOTUS Rule”). This definition is one of the most controversial and highly-litigated aspects of the CWA, if not all environmental law, because it has wide-ranging implications.

The definition of “waters of the United States” is so important because it sets the jurisdictional limits of the CWA. Under the CWA, EPA and the Army Corps have the power to regulate, among other things, the discharge of pollutants to navigable waters from a point source (33 U.S.C. § 1362(12)) and the discharge of dredged or fill material into navigable waters (33 U.S.C. § 1344). “Navigable waters” are defined in the CWA as “the waters of the United States, including the territorial seas.” 33 U.S.C. §1362(7). “Waters of the United States” is not defined further under the CWA, so the agencies have been left to try to craft a definition.

The Army Corps and EPA first proposed a WOTUS definition in 1977 and it has faced revisions and legal challenges ever since. The WOTUS definition has faced Supreme Court review in three previous cases, and is currently pending review in the case of Sackett v. U.S. Environmental Protection Agency, 19-35469, on appeal from the U. S. Court of Appeals for the Ninth Circuit.

The WOTUS definition was revised in 2015 by the Obama Administration to expand the definition and then in 2020 by the Trump Administration to narrow the definition; with both definitions facing swift legal challenges, including vacatur of the Trump rule in 2021. At issue in all of these rules is how to treat non-traditional navigable waters, like ephemeral bodies of water and wetlands.

The current WOTUS Rule goes back to re-establish the pre-2015 definition of WOTUS, and also incorporates guidance from the most recent Supreme Court case, the 2006 case of Rapanos v. U.S., 547 U.S. 715. In Rapanos, the Court did not reach a majority opinion. Justice Scalia authored a plurality opinion, Justice Kennedy wrote a concurring opinion, and Justice Stevens wrote a dissenting opinion. EPA and the Army Corps are incorporating Justice Kennedy’s opinion, which provided that wetlands and other bodies of water that have a “significant nexus” to more traditional navigable waters should be included in WOTUS. Id. at 759. This was in contrast to Justice Scalia’s opinion, which limited WOTUS to “only those wetlands with a continuous surface connection to bodies that are “waters of the United States” in their own right…” Id. at 739-42.

Thus, the new WOTUS Rule includes the following categories of waterbodies: (1) traditional navigable waters (e.g., certain large rivers and lakes); (2) territorial seas; (3) interstate waters; (4) impoundments; (5) tributaries; (6) adjacent wetlands; (7) and additional waters. To determine jurisdiction for tributaries, adjacent wetlands, and additional waters, the WOTUS Rule looks at whether the body of water meets either the “relatively permanent standard” or “significant nexus standard”, as follows:

• Relatively Permanent Standard is a test that readily identifies a subset of waters that will virtually always significantly affect traditional navigable waters, the territorial seas, or interstate waters. To meet the relatively permanent standard, the waterbodies must be relatively permanent, standing, or continuously flowing waters connected to traditional navigable waters or waters with a continuous surface connection to such relatively permanent waters or to traditional navigable waters, the territorial seas, or interstate waters.
• Significant Nexus Standard is a test that clarifies if certain waterbodies, such as tributaries and wetlands, are subject to the Clean Water Act based on their connection to and effect on larger downstream waters that Congress fundamentally sought to protect. A significant nexus exists if the waterbody (alone or in combination) significantly affects the chemical, physical, or biological integrity of traditional navigable waters, the territorial seas, or interstate waters.

The WOTUS rule will be published in the Federal Register in the next few days, and will be effective 60 days after publication. Legal challenges will surely follow, and its future longevity will likely be determined by the Supreme Court in the Sackett case. EPA had tried to avoid Supreme Court review based on the fact that it was working on a revised rule, but that argument was not successful. Therefore, it is likely that the Court will go forward and make a ruling on WOTUS, potentially undermining the basis for the current WOTUS rule. As always, we will keep you updated on key developments in the Corporate Environmental Lawyer Blog.

More information about the new WOTUS Rule is available on EPA’s website.