In Hawai’i Wildlife Fund v. County of Maui, No. 15-17447 (9^th Cir. Feb. 1, 2018), the U.S. Court of Appeals for the Ninth Circuit affirmed a district court ruling that  the County’s injection wells are “point sources” from which the County discharged pollutants in the form of treated effluent into groundwater, through which the pollutants then entered a “navigable water,” the Pacific Ocean, and therefore violated the Clean Water Act (“CWA”). While discharges to groundwater do not necessarily trigger CWA requirements, a potential circuit split is brewing on whether these indirect discharges of pollutants to WOTUS through discharges to groundwater are regulated under the CWA.

The increase in litigation involving groundwater mirrors a 2017 Gallup poll report that Americans are more concerned about water pollution than they have been since 2001. The County of Maui decision sets up the possibility for increased federal permit requirements for those discharging wastewater through groundwater disposal wells and those detaining stormwater and allowing it to seep into groundwater that ultimately reaches navigable waters.

The CWA prohibits a discharge of a pollutant to navigable waters from a “point source” without a National Pollution Discharge Elimination System (“NPDES”) permit. A discharge is defined as “any addition of any pollutant” into WOTUS from a “point source”.  A “point source” is defined as “any discernable, confined and discrete conveyance.” Examples of point sources in the CWA regulations include a pipe, ditch, channel, or vessel.  Specifically excluded from the definition of “point source” are agricultural storm water discharges, irrigation return flows, and “non-point” sources.

In County of Maui, the County injected 3 to 5 million gallons of recycled, treated wastewater daily for years into four injection wells a half-mile inland, without an NPDES permit. The injection wells are long pipes that carry effluent about 200 feet underground into a shallow groundwater aquifer.  The wastewater made its way through groundwater, which is not regulated generally under the CWA, to the Pacific Ocean, a “water of the United States” under the CWA.  A tracer dye study showed that dye was visible in the ocean 84 days after it was injected into the wells. The plaintiffs argued that the County’s effluent injections were discharges from a point source (the wells) through groundwater and to navigable water, causing damage to coral reefs and violating the CWA. The County argued that the discharge from the point source must be made directly to a navigable water in order to fall under the CWA.

The Ninth Circuit held that the indirect discharge through groundwater to the Pacific was subject to regulation under the CWA and required a permit.  The court rejected arguments that a point source must discharge directly into navigable water to trigger CWA regulation, holding instead that it is enough for the discharge to come from a point source (here, the wells.) The court “assumed without deciding” that the groundwater here was not a “point source” or navigable water. The opinion emphasized that although there was no direct discharge to the Pacific, there was a “fairly traceable” connection established through the tracer dye studies, showing “the functional equivalent of a discharge into navigable waters” by the County.  In doing so, the Ninth Circuit considered Justice Scalia’s plurality opinion in United States v. Rapanos “for its persuasive value,” which states that the CWA does not prohibit the “‘addition of any pollutant directly to navigable waters from any point source’ but rather the ‘addition of any pollutant to navigable waters.’” The Ninth Circuit decision raises uncertainty about how much of a connection is necessary between groundwater and navigable water to require a permit under the CWA for indirect discharges.

District courts are split on whether the CWA governs releases of pollutants into groundwater that eventually carries the pollutants to WOTUS.  In Upstate Forever v. Kinder Morgan Energy Partners, an underground pipe leaked about 370,000 gallons of petroleum into groundwater and soil.  The leak was repaired and is still being remediated. Plaintiffs argued that the groundwater carried petroleum to navigable waters.  The district court held that the migration of pollutants through soil and groundwater is “non-point source” pollution and therefore not regulated under the CWA and dismissed the action. The Fourth Circuit heard argument on appeal on December 7, 2017.  The case sets up a potential split in the circuits with County of Maui that soon could bring the issue before the U.S. Supreme Court.

On February 20, 2018, EPA requested comment on whether “EPA should review and potentially revise its previous statements” about “pollutant discharges from point sources that reach jurisdictional waters via groundwater or other subsurface flow that has a direct hydrological connection to a jurisdictional surface water” and specifically (i) whether  “subjecting such releases to CWA permitting is consistent with the text, structure, and purposes of the CWA;” (ii) would “those releases be better addressed through other federal authorities than the CWA NPDES permitting program;” and (iii) “whether some or all  such releases are adequately addressed through existing state statutory or regulatory programs” or federal programs. EPA also seeks comment on whether it should clarify statements regarding the meaning and circumstances under which such discharges are “considered ‘direct’ in order to reduce regulatory uncertainties.” 83 FR 7126 (Feb. 20, 2018).  The comment period closes May 21, 2018.