Supreme Court Articulates New Test for Clean Water Act Permitting in County of Maui Decision

(April 24, 2020) – In a highly anticipated Clean Water Act (CWA) decision, the U.S. Supreme Court this week held that discharges originating from point sources that reach navigable waters through groundwater and other diffuse media are subject to CWA National Pollutant Discharge Elimination System (NPDES) permitting requirements if they are the “functional equivalent” of discharges made directly into those waters. 

Specifically, the Court in County of Maui v. Hawaii Wildlife Fund overturned a 2018 Ninth Circuit Court of Appeals decision requiring an NPDES permit for discharges from a wastewater treatment facility that migrated via groundwater to the Pacific Ocean based on the fact that they were “fairly traceable” to the facility’s underground injection wells. 

NACWA filed multiple briefs in the case in support of Association member the County of Maui.

The 6-3 opinion, authored by Justice Breyer and joined by Chief Justice Roberts and Justices Ginsburg, Sotomayor, Kagan, and Kavanaugh, rejects as “too extreme” both the Ninth Circuit’s decision that all discharges reaching a navigable water that are “fairly traceable” back to a point source fall under NPDES coverage, as well as the County’s position that only discharges made directly from a point source such as a pipe or well into a navigable water trigger NPDES permitting requirements.

Instead, the Court articulated a new test that the CWA requires an NPDES permit “when there is a direct discharge from a point source into navigable waters or when there is the functional equivalent of a direct discharge.”  The primary factors to be considered under this test are the pollutant’s transit time and distance traveled before reaching the navigable water, with other relevant factors including the nature of the material through which the pollutant travels, the extent to which the pollutant is diluted or chemically altered in transit, the amount of pollution entering the navigable waters relative to the amount leaving the point source, the manner by which the pollutant enters the navigable water, and the degree to which the pollutant maintains its specific identity. 

According to the Justices, this middle-ground position appropriately takes into account concerns raised by NACWA and a host of other water and industry groups that the Ninth Circuit’s test inappropriately expanded the scope of CWA coverage well beyond Congressional intent, without creating the “large and obvious loophole” in the NPDES program that excluding all discharges not made directly into surface waters would create.

NACWA will be providing a further analysis of this decision in the coming days. We will also be convening an expert panel to discuss its implications for the clean water sector on our June 10th Legal Hot Topics webinar. In the interim, please contact Nathan Gardner-Andrews or Amanda Aspatore.