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Supreme Court Rules that the Clean Water Act May Cover Discharges to Groundwater in County of Maui v. Hawaii Wildlife Fund Case

by E. Jacob Lubarsky and Jon-Erik W. Magnus

In one of the most high profile environmental cases on the Supreme Court’s docket this term, County of Maui v. Hawaii Wildlife Fund, the Court held that the Clean Water Act (“CWA”) may be used to regulate pollution that travels through groundwater.[1] Specifically, the Court held that a CWA permit is required where a discharge into groundwater is the “functional equivalent” of a direct discharge to navigable waters. The Court did not establish a bright-line definition of “functional equivalence.” Rather, the Court identified a number of factors to be considered, with “time and distance” the most important, leaving it to lower courts in later cases to flesh out “additional guidance” on what “functional equivalence” means, thus guaranteed continuing litigation and disputes over the issue.

The case involves the County of Maui’s use of injection wells – where treated wastewater is injected into the ground between impermeable layers of rocks to avoid polluting fresh water supplies – to dispose of treated sewage water. The County had been operating, for years, with state permits and with the assurance from local authorities that it did not require a National Pollutant Discharge Elimination System (“NPDES”) permit under the CWA. When environmental groups established through tracer dye studies that water containing more than de minimis amounts of contaminants injected into those wells was reaching the Pacific Ocean, the group sued the County alleging CWA violations for discharging without the required permit.

At the appellate level, the Ninth Circuit ruled that the CWA regulates the discharge of contaminants into groundwater that subsequently reaches navigable waterways. The Ninth Circuit held that because the injection wells were point sources and the pollution reached a traditionally regulated body of water, the County needed an NPDES permit under the CWA for its discharges to groundwater. The Ninth Circuit based its decision, not on the point source being directly discharged to navigable water, but the pollutants being “fairly traceable” through the groundwater that eventually flowed to the Pacific Ocean.[2]

The Supreme Court reversed. Justice Stephen Breyer, writing for a 6-3 majority that included Chief Justice John Roberts and Justice Brett Kavanaugh, created a new test for courts to use to determine when the CWA requires a permit for point source discharges that travel through groundwater to navigable waters. Justice Breyer wrote that a permit is required “when there is a direct discharge from a point source into navigable waters or when there is the functional equivalent of a direct discharge.” Justice Breyer articulated two key factors for “most cases, but not necessarily every case” in determining whether indirect pollution needs permits: (1) the distance pollution must travel to reach a federal waterway; and (2) the time it takes to get there. In an attempt to add some clarity to a potentially murky rule, the Court identified circumstances where “a pipe ends a few feet from navigable waters and the pipe emits pollutions that travel those few feet through groundwater (or over the beach)” as circumstances where a permit would be needed. Whereas when “the pipe ends 50 miles from navigable waters” and the discharge “.. ends up in navigable waters only many years later…” a permit is likely not needed. The Court also noted, without further specificity, some additional considerations including the nature of material pollution travels through; the extent to which pollution is diluted or chemically changed; and the amount that makes it to a federal waterway.

The Court’s decision is contrary to an EPA-released policy last year in response to the Ninth Circuit’s “fairly traceable” decision. The EPA policy stated that any pollution that moves through groundwater before reaching federal waters is not subject to the CWA’s permitting requirements – a position divergent from earlier EPA interpretations of the CWA. But the Court declined to give any deference to the EPA’s new approach, stating that following the new policy “would open a loophole allowing easy evasion of the statutory provision’s basic purposes.” Justice Breyer stated that “neither the Solicitor General nor any party” requested the Court to defer to the EPA’s recent guidance, which stated that all releases of pollutants to groundwater are categorically excluded from CWA permitting requirements. Despite the fact that the Court “often pay[s] particular attention to an agency’s views in light of the agency’s expertise in a given area, its knowledge gained through practical experience, and its familiarity with the interpretive demands of administrative need[,]” here, EPA’s interpretation was “neither persuasive nor reasonable,” given the significant regulatory gap it would create in CWA permitting provisions.

In dissent, Justice Clarence Thomas was joined by Justice Neil Gorsuch. And Justice Samuel Alito issued his own dissent. Both dissents supported a test requiring a permit only “when a point source discharges pollutants directly into navigable waters,” although for slightly different reasons, with both dissents claiming to be based on the statutory text and structure.

Through this decision, the Court likely eliminated circumstances, at the extremes of time and distance, that may require permitting under the CWA while at the same time the Court has certainly added additional uncertainly to CWA permitting decisions. The result could be years of administrative, agency, and permittee wrangling over permitting requirements, as well as additional litigation to determine if permits are needed and to further shape the arguably-ambiguous rule in this decision.



Rogers Joseph O’Donnell provides its clients with guidance on compliance with regulatory and environmental laws that affect their business and has formed a taskforce dedicated to steering businesses during this unprecedented time. For compliance advice or defense of claims, attorneys Robert C. Goodman, E. Jacob Lubarsky, and Jon-Erik Magnus are available to assist.


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[1] A copy of the Court’s opinion can be found here.

[2] See our previous analysis of lower courts’ decisions related to the issues in this case here and here.

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