On February 1, 2018, the U.S. Court of Appeals for the Ninth Circuit held that the Clean Water Act (“CWA”) regulates discharges of pollutants that travel indirectly through groundwater into a navigable “water of the United States,” such as the ocean.
In Hawaii Wildlife Fund v. Cty. of Maui, 881 F.3d 754 (9th Cir. 2017), environmental groups sued the County of Maui, alleging that it violated the CWA by injecting treated wastewater into the groundwater through four underground injection wells without a National Pollutant Discharge Elimination System (“NPDES”) permit. A tracer dye study was conducted by the United States Environmental Protection Agency (“EPA”) and other organizations, which showed that the tracer dye introduced into the wells emerged along the ocean floor near a beach park, half a mile away from the wells.
Relying heavily on the tracer dye study, the Ninth Circuit affirmed the district court’s decision holding the County liable for unpermitted discharges in violation of the CWA. The Ninth Circuit held the County liable under the CWA because,
(1) the County discharged pollutants from a point source, (2) the pollutants are fairly traceable from the point source to a navigable water such that the discharge is the functional equivalent of a discharge into the navigable water, and (3) the pollutant levels reaching navigable water are more than de minimis.
881 F.3d at 765.
Less than a month after the Ninth Circuit’s ruling came out, EPA opened a comment period on whether the agency should consider clarifying the CWA’s coverage of discharges of pollutants via a direct hydrologic connection to surface water. The comment deadline is May 21, 2018.
Similar cases involving alleged indirect discharges through groundwater to nearby surface waters are currently pending in the Fourth and Sixth Circuits.
This article was prepared by Christine A. Terada.