Knowing when Clean Water Act permitting is required is a question for the ages that has wreaked havoc on many projects in the decades since EPA first attempted to define the term “waters of the United States,” also known as “WOTUS.” Since the 1970s, this definition has been the subject of great controversy, with three U.S. Supreme Court cases, the Obama administration, the Trump administration, and the Biden administration, all attempting to craft definitions that capture the extent of federal authority over navigable waters.

The never-ending saga of defining WOTUS continues, as on Jan. 18, 2023, EPA and the U.S. Army Corps of Engineers published a final WOTUS rule in the Federal Register based on the pre-2015 definition. The new rule will become effective on March 20, 2023.

The WOTUS definition is critical to understanding which waters are regulated by the Clean Water Act, which prohibits the discharge of pollutants from a point source into “navigable waters” unless otherwise authorized to do so under the Clean Water Act. “Navigable waters” is further defined to mean “the waters of the United States, including the territorial seas.” The term is fairly obvious as applied to waterbodies that are traditionally considered navigable, such as rivers, lakes, and streams. But the analysis is much trickier when applied to ephemeral streams, ditches, and isolated wetlands with little or no apparent connection to a larger water body.

Whether a federal permit is required before a person can discharge to one of these smaller, more isolated bodies of water, can be a very expensive proposition — both from the permitting and enforcement standpoint. As a result, the WOTUS definition and the limits of federal authority have been the subject of significant debate and litigation since the dawn of the Clean Water Act. Additionally, the various court decisions and rules issued by federal agencies in 2015, 2019, and 2020 have resulted in regulatory whiplash for anyone hoping to rely on the definition.

In this final rule, EPA and the Army Corps of Engineers address the ever-changing landscape of WOTUS and define WOTUS to include:

• Traditional navigable waters, the territorial seas, and interstate waters (paragraph (a)(1) waters);
• Impoundments of “waters of the United States” (paragraph (a)(2) impoundments);
• Tributaries to traditional navigable waters, the territorial seas, interstate waters, or paragraph (a)(2) impoundments when the tributaries meet either the relatively permanent standard or the significant nexus standard (jurisdictional tributaries);
• Wetlands adjacent to paragraph (a)(1) waters, wetlands adjacent to and with a continuous surface connection to relatively permanent paragraph (a)(2) impoundments, wetlands adjacent to tributaries that meet the relatively permanent standard, and wetlands adjacent to paragraph (a)(2) impoundments or jurisdictional tributaries when the wetlands meet the significant nexus standard (jurisdictional adjacent wetlands); and
• Intrastate lakes and ponds, streams, or wetlands not identified in paragraphs (a)(1) through (4) that meet either the relatively permanent standard or the significant nexus standard (paragraph (a)(5) waters).

To determine whether a tributary, adjacent wetland, or additional water falls within this definition of WOTUS and is therefore subject to the Clean Water Act, EPA’s final rule relies on two standards: (1) the Relatively Permanent test; and (2) the Significant Nexus tests. The relatively permanent test provides important efficiencies and clarity for regulators and the public by readily identifying a subset of waters that will virtually always significantly affect paragraph (a)(1) waters. To satisfy the relatively permanent standard, the waterbodies must be relatively permanent, standing, or continuously flowing waters connected to paragraph (a)(1) waters or waters with a continuous surface connection to such relatively permanent waters or to paragraph (a)(1) waters.

The Significant Nexus test clarifies whether 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.

Notably, EPA’s final rule excludes the following from its definition of WOTUS:

• Prior converted cropland, adopting USDA’s definition and generally excluding wetlands that were converted to cropland prior to Dec. 23, 1985.
• Waste treatment systems, including treatment ponds or lagoons that are designed to meet the requirements of the Clean Water Act.
• Ditches (including roadside ditches), excavated wholly in and draining only dry land, and that do not carry a relatively permanent flow of water.
• Artificially irrigated areas that would revert to dry land if the irrigation ceased.
• Artificial lakes or ponds, created by excavating or diking dry land that are used exclusively for such purposes as stock watering, irrigation, settling basins, or rice growing.
• Artificial reflecting pools or swimming pools, and other small ornamental bodies of water created by excavating or diking dry land.
• Water filled depressions, created in dry land incidental to construction activity and pits excavated in dry land for the purpose of obtaining fill, sand, or gravel unless and until the construction operation is abandoned and the resulting body of water meets the definition of “waters of the United States.”
• Swales and erosional features (e.g., gullies, small washes), that are characterized by low volume, infrequent, or short duration flow.

EPA released statements corresponding to the rule claiming that the definition of WOTUS minimizes the uncertainty surrounding the precise bounds of regulable waters and establishes limits to the waters subject to federal protection. But the broad nature of the new definition is likely to require permitting for projects that would have been exempted by the 2019 and 2020 rules, thereby increasing costs for and imposing delays on a significant number of infrastructure, transportation, and energy projects.

The announcement of EPA’s defining WOTUS rule comes after EPA and the U.S. Army Corps of Engineers announced their intent to redefine WOTUS on June 9, 2021, and after they announced the proposed final rule on Dec. 30, 2022. Throughout the rulemaking process, EPA received abundant comments from many individuals, entities, states, and interest groups.

Entities with projects that are likely to involve discharges to surface waters should review the new definition with care and consult with qualified environmental consultants and counsel, particularly given the broadened scope of waters that may now be subject to federal jurisdiction. This is of added importance in states that do not have isolated wetlands permitting programs, where federal jurisdiction may now apply to waters that were previously not subject to any permitting requirements.

Helpful links:

• Federal Register for the Revised Definition of “Waters of the United States.”
• Docket for the matter (Docket ID No. EPA-HQ-OW-2021-0602).
• Public Fact Sheet on EPA’s Final Rule: Revised Definition of “Waters of the United States.”
• EPA’s website dedicated to WOTUS.

For more information, please contact a member of Taft’s Environmental practice group.