On January 23, 2020, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (USACE) (collectively, “Agencies”) finalized the Navigable Waters Protection Rule, which redefines the jurisdictional scope of the Clean Water Act (CWA). This completes the two-step process outlined by the Trump administration to repeal and replace the Obama administration’s Clean Water Rule. If implemented, the Navigable Waters Protection Rule would significantly affect the way waters (particularly wetlands) are regulated. This Client Alert provides context on the new rule and summarizes key changes.


The replacement of the Clean Water Rule is the latest development in a long history of attempts by all three branches of the federal government to define the jurisdictional scope of the CWA. The primary jurisdictional term in the CWA is “navigable waters.”1 “Navigable waters,” in turn, is defined to mean “the waters of the United States, including the territorial seas.”2 If a body of water is not a Water of the United States (WOTUS), then it does not fall within CWA jurisdiction and is, therefore, not subject to CWA prohibitions. Despite this, Congress did not further define WOTUS, leaving it to the Agencies.

The Agencies have promulgated a number of rules and guidance documents to clarify the meaning of WOTUS. In the 1970s, the Agencies agreed on a unified definition of WOTUS that remained largely (though not entirely) unchanged until they published the Clean Water Rule in 2015.3 However, that does not mean the scope of the waters covered remained consistent. Over the years, the Supreme Court has issued a series of decisions interpreting the Agencies’ definition of WOTUS. The third major Court case on WOTUS, Rapanos v. United States, set the backdrop for the Clean Water Rule and its successor, the Navigable Waters Protection Rule.

In Rapanos v. United States, the Supreme Court considered whether the Agencies could define WOTUS to include isolated wetlands with some adjacency to navigable waters.4 Answering this seemingly simple question injected a lot of ambiguity into the scope of the meaning of WOTUS, largely because the Court failed to reach a majority opinion. The plurality opinion, authored by Justice Scalia, held that WOTUS should be limited to only relatively permanent bodies of water and that only wetlands with a continuous surface connection to WOTUS should be classified as adjacent wetlands for jurisdictional purposes.5 Justice Kennedy authored a narrower rationale, finding that water or wetlands with a “significant nexus” to navigable waters constituted WOTUS.6 In the absence of a majority opinion, Justice Kennedy’s narrower rationale should have controlled, but the case nonetheless added uncertainty to the scope of CWA jurisdiction.

Partially in response to the confusion created by Rapanos, the Agencies promulgated the Clean Water Rule in 2015.7 Although intended to clarify the scope of WOTUS, the Clean Water Rule sparked controversy from all sides. Multiple lawsuits were filed, which resulted in the Sixth Circuit issuing a nationwide stay.8

Repealing the Clean Water Rule

When President Trump took office, he issued an Executive Order that directed the Agencies to review and rescind or revise the Clean Water Rule.9 In response, the Agencies announced a two-step plan in July 2017 to rescind the Clean Water Rule and then replace it.10

The Agencies’ attempt to repeal and replace the Clean Water Rule was heavily litigated, which caused a jurisdictional mess. The end result of the litigation was the Clean Water Rule going into effect in some states (those in which the Clean Water Rule had not been enjoined), but not others (those states in which the Clean Water Rule had been enjoined).11 Ultimately, the Clean Water Rule went into effect in 22 states, including New York, while remaining enjoined in the rest of the country.12

On December 23, 2019, the rule repealing the Clean Water Rule went into effect, completing the first step of the two-step repeal and replace process announced in July 2017.13 Upon going into effect, the repeal rule codified the earlier, pre-Clean Water Rule definition of WOTUS. As a result, the 22 states that had been operating under the Clean Water Rule returned to the earlier definition of WOTUS.

The Navigable Waters Protection Rule

On January 23, 2020, the Agencies finalized the second of the two-step process by finalizing the Navigable Waters Protection Rule. The Agencies’ claim that the new rule will clarify and streamline the definition of WOTUS, and therefore, make jurisdictional determinations simpler and more efficient. The Navigable Waters Protection Rule aims to accomplish this by creating certain categories of jurisdictional waters; excluding specific, non-jurisdictional waters; and defining terms to further delimit jurisdictional waters.14 These efforts are summarized below.

Categories of Jurisdictional Waters. The Navigable Waters Protection Rule establishes four categories of jurisdictional waters. These include:

  • Traditional navigable waters
  • Perennial and intermittent tributaries that contribute surface flow to traditionally navigable waters
  • Certain lakes, ponds and impoundments of jurisdictional waters
  • Wetlands that are adjacent to jurisdictional waters15

Listed Exclusions. The Navigable Waters Protection Rule excludes from WOTUS all waters not within the four categories listed above. In addition, it also excludes 11 specific types of waters. These include:

  • Groundwater
  • Ephemeral features that flow in response to precipitation
  • Diffuse stormwater runoff
  • Ditches that are not traditionally navigable waters
  • Prior converted cropland
  • Artificially irrigated areas
  • Artificial lakes and ponds
  • Water-filled depressions
  • Stormwater control features
  • Groundwater recharge
  • Waste treatment systems16

Defined Terms. The Navigable Waters Protection Rule also defines previously undefined terms. The most significant definitions include the following:

  • The term “adjacent wetlands” is defined to mean any wetland that is connected to a jurisdictional water by (a) physically abutting the jurisdictional water, (b) inundation by flooding in a typical year from a jurisdictional water, or (c) physical separation from a jurisdictional water by a natural or artificial barrier.17
  • The term “ephemeral” is defined to mean surface water that flows in response to precipitation.18
  • The term “intermittent” is defined to mean surface water flowing continuously during certain times of the year and more than in response to precipitation.19
  • The term “perennial” is defined to mean surface water flowing continuously, year-round.20
  • The term “typical year” is defined to mean when precipitation and other climatic variables are within the normal periodic range for a specific geographic area.21

Removal of “Significant Nexus” Test. The Navigable Waters Protection Rule does not carry over the “significant nexus” test that was part of the Clean Water Rule. The Clean Water Rule adopted the significant nexus test articulated by Justice Kennedy in Rapanos to include, on a case-by-case basis, certain waters that had a significant physical, chemical or biological connection to traditionally navigable waters.22 Citing efficiency, the Navigable Waters Protection Rule dropped the significant nexus test as a means to assert jurisdiction.

Implications of Navigable Waters Protection Rule

The Navigable Waters Protection Rule is scheduled to go into effect 60 days after the Agencies publish it in the Federal Register. Should the Navigable Waters Protection Rule survive legal challenges and go into effect, it promises fewer jurisdictional waters and more efficient jurisdictional determinations.

Legal Challenges. There have already been a number of challenges to the repeal of the Clean Water Rule.23 In the coming months, there will almost certainly be challenges to the Navigable Waters Protection Rule. As with the challenges to the Clean Water Rule, future litigation will undoubtedly create regulatory uncertainty.

Fewer Jurisdictional Waters. By limiting the categories of jurisdictional waters through definitions, exclusions and moving away from the significant nexus test, the Navigable Waters Protection Rule will limit the scope of WOTUS and, therefore, CWA jurisdiction.

This is particularly true of tributaries and adjacent wetlands. Under the Navigable Waters Protection Rule, tributaries are only jurisdictional if they have intermittent or perennial flow into traditionally navigable waters. This is a significant change from the Clean Water Rule regulations and those existing prior to it. Before the Clean Water Rule, WOTUS included all tributaries without qualification. The Clean Water Rule established a narrower definition of tributaries that included waters characterized by the presence of indicators of flow and those with a significant nexus to downstream waters.24 By further restricting WOTUS to tributaries with intermittent or perennial flow, the Navigable Waters Protection Rule will reduce the number of tributaries subject to CWA jurisdiction.

Similarly, by narrowing the definition of adjacent wetlands, the Navigable Waters Protection Rule will cover fewer wetlands than would have been jurisdictional under either the Clean Water Rule or the earlier regulations. Under the new rule, jurisdictional wetlands will no longer include isolated wetlands, wetlands adjacent to other wetlands or those with a significant nexus to traditionally navigable waters.

More Efficient Jurisdictional Determinations. In addition to fewer jurisdictional waters, the Navigable Waters Protection Rule promises to make jurisdictional determinations quicker, more consistent and more certain. This is largely a function of eliminating the significant nexus test, but also because the rule limits the scope of WOTUS. By removing the significant nexus test, the rule abandons case-by-case jurisdictional determinations in favor of bright-line rules. Whether this will result in more efficient determinations is an open question, as categorizing certain water bodies will still require some field observations.

What Happens Next

The Navigable Waters Protection Rule promises the regulated community more efficient and consistent jurisdictional determination, but only if it survives likely legal challenges. Until then, the regulated community will continue to face an uncertain regulatory environment and should carefully consider its options before taking actions that may affect jurisdictional waters.