William & Mary Environmental Law and Policy Review


The meaning of “waters of the United States” under the Clean Water Act (“CWA”) has been debated in Congress, federal agencies, and courtrooms across the country for almost fifty years. Despite the longstanding attention to the term, most consider the term even more unclear today than in 1972 when the CWA was adopted. However, a methodical examination of the statutory and regulatory history and the U.S. Supreme Court decisions on the issue reveal more consensus than previously understood. In addition, this focused examination shows that the debate centers on one problem that the arguments rarely acknowledge: wetlands adjacent to a “tributary.” Specifically, litigants and agencies attempt to show that the wetland at issue lies close to some type of water, whether a ditch, drain, or creek. If that water eventually reaches a navigable water, no matter how indirect or attenuated the path, the wetland is arguably jurisdictional. This Article distills the issues and clarifies the agreements and controversies surrounding “waters of the United States.”

The meaning of the phrase “waters of the United States” has been debated in the legislature, federal agencies, and courtrooms across the country since Congress adopted the CWA in 1972. The debate intensified beginning in 1985 and now forms the focus of much rule-making and litigation. Section 404 of the CWA prohibits the discharge of dredged or fill material into the “navigable waters.” Navigable waters mean the “waters of the United States, including the territorial seas.” The term waters of the United States, as used in the CWA, was not further defined by Congress.

This Article first provides a brief overview of the history and background of the CWA and the regulations thereunder. The history reflects a shift in focus from commerce to environmental protection. U.S. Supreme Court case law interpreting the meaning of waters of the United States (“WOTUS”) is then examined. The Article then reviews the 2015 WOTUS Rule (“Obama Rule”) and the 2020 Navigable Waters Protection Rule (“Trump Rule”). The Article also explores the applications of deference to the agency in various cases and how judicial deference may evolve in the future. Given the attention of case law on the definition of tributaries and adjacency of wetlands to tributaries, those issues form the Article’s focus.