In the case of Hawaii Wildlife Fund, et al., v. County of Maui, decided on February 1, 2018, the U.S. Court of Appeals for the Ninth Circuit affirmed the decision of the U.S. District Court for Hawaii that the County of Maui’s longtime use of state-permitted wastewater disposal wells at is municipal waste water treatment plant required National Pollutant Discharge Elimination System (NPDES) permits because the indirect discharge of pollutants into the Pacific Ocean through groundwater triggered the NPDES provisions of the Clean Water Act (CWA). This is a significant case, and it may have significant ramifications for CWA permitting and enforcement.

Various tracer dye studies concluded that there was a hydrological connection between the treated wastewater effluent and the coastal waters. All parties agreed that the disposal wells were “point sources” under the CWA. However, the County of Maui argued that the point source itself must covey the pollutants directly into the navigable waters of the Pacific Ocean, and that an indirect discharge through groundwater does not trigger the permitting requirements of the CWA.

The Court of Appeals rejected this argument, holding that it agrees with those cases which hold that an indirect discharge from a point source (here, the injection wells) “suffices for CWA liability to attach.” Moreover, “that the groundwater plays a role in delivering the pollutants from the wells to the navigable water does not preclude liability under the statute.”

Even Justice Scalia’s opinion in the Rapanos v. U.S. can be read as supporting this conclusion. Indeed, “the discharge into groundwater in this case “is the functional equivalent of a “discharge into navigable water.” Lastly, CWA Section 1342(b)(1)(D), pertaining to permitted injection well disposal operations, is no bar to this lawsuit, nor is the fact that the County, which for many years was proceeding under the assurance from local permitting authorities that no NPDES permit was required, amounts to a due process violation because it never received proper notice that it was in violation of the law.