What is a “Water of the United States?”

According to the joint press release issued by the Environmental Protection Agency and the Army Corps of Engineers earlier this year, the agencies' "Navigable Waters Protection Rule" will "eliminate the confusion" over the scope of the Clean Water Act and provide "much needed regulatory certainty and predictability for American farmers, landowners and businesses." (The agencies issued a pre-publication version of the rule in January, but did not officially publish it in the Federal Register until April; the rule took effect on June 22).

In the same press release,the agencies optimistically declared that the rule "ends decades of uncertainty over where federal jurisdiction beings and ends." But two recent district court rulings addressing challenges to the new rule -- decided on the same day in June and reaching diametrically opposite conclusions -- demonstrate that, when it comes to demarcating the reach of the Clean Water Act, clarity and certainty remain painfully elusive.

The long and confusing saga leading up to the adoption of the new rule cries out for a clear and stable definition of the key statutory phrase "waters of the United States." The Supreme Court in 2006 issued its splintered 4-1-4 decision in the Rapanos case, which overturned the historically broad interpretation of federal jurisdiction under the Clean Water Act but confusingly offered two competing replacement standards. Rapanos v. United States, 547 U.S. 715 (2006). While Justice Antonin Scalia's plurality opinion endorsed a narrow "continuous surface connection" test, Justice Anthony Kennedy's tie-breaking concurring opinion articulated an open-ended, multi-factor "significant nexus" test.

Most lower courts applying Rapanos adopted the significant nexus test as the controlling standard, and the agencies published joint guidance in 2008 on how to apply it. But the interpretive, non-binding guidance did little to clear up the confusion and led to cries for a formal rulemaking proceeding to establish a clear regulatory standard.

Fast forward to the adoption of the "Clean Water Rule" by the Obama administration in 2015, which was based on a broad reading of Justice Kennedy's significant nexus test. Like the current rule, the 2015 regulation was intended to provide clarity and predictability, albeit with a very different vision of the scope of federal jurisdiction. But a flurry of court decisions across the country, combined with a sequence of regulations adopted the Trump administration to suspend the effectiveness of the 2015 regulation, and then to repeal it altogether, created a bizarre situation where the 2015 regulation applied in some states but not others -- necessitating a color-coded map on the EPA's website to indicate which rules applied where.

With the new Navigable Waters Protection Rule, the categories of federally jurisdictional waters have been simplified to include only traditional navigable waters (such as rivers and bays); naturally occurring tributaries that contribute surface flow to such waters either perennially or intermittently; narrowly defined lakes, ponds and impoundments; and wetlands that are "adjacent" to a waterbody in the first three jurisdictional categories. The most notable aspect of the new rule is that it hews much closer to Justice Scalia's continuous surface connection test than to the previously prevailing significant nexus test.

In the preamble to the new rule, the agencies emphasized the "long history of controversy and confusion over the definition of 'waters of the United States,'" the continued litigation since Rapanos, and the lack of clear guidance on "how far up the watershed federal jurisdiction extends, and what connection is required for waters to be considered part of the regulated tributary system." The agencies accordingly explained that "replacing the multi-factored case-specific significant nexus analysis with categorically jurisdictional and categorically excluded waters" will provide clarity to the regulated community, while also reflecting "the most faithful way" of interpreting federal authority under the Clean Water Act.

Not surprisingly, a coalition of 17 states and other public agency plaintiffs, led by the state of California, sued to challenge the new rule in May in the Northern District of California, with 23 other states intervening in the case in support of the rule. The state of Colorado brought another lawsuit to challenge the rule in May in the District of Colorado. In each case, the plaintiffs filed a motion for a preliminary injunction in order to stay the effectiveness of the new rule until the case is resolved. Both courts issued rulings on June 19 and the starkly contrasting decisions illustrate that continued litigation and uncertainty over the indeterminate phrase "waters of the United States" is likely to persist until the Supreme Court weighs in again.

In the California case, the court denied the motion for a preliminary injunction, finding that the plaintiffs are unlikely to prevail on their claims when the case reaches the merits phase. California v. Wheeler, 20-cv-03005-RS (N.D. Cal. June 19, 2020). The court relied on the notion of judicial deference to agency rulemaking proceedings, finding that the terms of the statute are ambiguous and that the agencies therefore have discretion and flexibility to interpret the law's meaning -- and that nothing in the Supreme Court's Rapanos decision compelled the agencies to select the broader "significant nexus" test over the narrower "continuous surface connection" test as the basis for their new regulation. The court stated: "In the absence of precedent construing what must be included as 'waters of the United States,' plaintiffs are left with little more than policy arguments that the narrowness of the 2020 Rule serves poorly to carry out the objectives of the CWA. As compelling as those arguments may be, they do not provide a sufficient basis for a court to substitute its judgment for the policy choices of the [agencies]."

In the Colorado Case, the court reached the opposite conclusion. Colorado v. U.S. Environmental Protection Agency, 20-cv-1461-WJM-NRM (D. Colo. June 19, 2020). It found that the plaintiffs were likely to succeed on the merits of their claims and it therefore ordered that the rule is stayed and may not be applied or enforced within the state of Colorado. The court explained that "[i]t is notoriously difficult to understand what Rapanos is for ... , but is much simpler to understand what Rapanos is against." Using this framework, the court reasoned that a majority of the justices in Rapanos -- Justice Kennedy plus the four justices who would have upheld the broad historical view of federal jurisdiction -- were "against" Justice Scalia's "surface connection test" because it was too narrow. And because the new Rule is "self-consciously" based on Justice Scalia's test, the court found that the plaintiffs had met their preliminary injunction burden of showing a likelihood of success for their challenge. The court explained that while nothing in Rapanos forecloses the agencies from reinterpreting the phrase "waters of the United States" as part of their rulemaking process," the Supreme Court's decision in that case "does foreclose the reinterpretation at issue here." In its expedited appeal of the Colorado district court's ruling to the 10th U.S. Circuit Court of Appeals, the federal government argues that the issue in Rapanos was not what the agencies must regulate, but what they may.

It remains to be seen how the courts will ultimately resolve the pending challenges. And apart from the court cases, a change in administration in January 2021 would almost certainly result in the repeal of the Navigable Waters Protection Rule and the adoption of new and different Clean Water Act regulations. Congress could resolve the substantial litigation and regulatory uncertainty by enacting a more precise statutory definition of "waters of the United States." But lawmakers have been unable to resolve this critical ambiguity since the act was first passed in 1972. 