EPA Wades into Murky Groundwater Debate – Accepting Comments through January 12

On December 4, 2020, the Environmental Protection Agency (“EPA”) issued a draft guidance memo to help explain when the National Pollutant Discharge Elimination (“NPDES”) Program requires permits for discharges of polluted water to groundwater. The EPA guidance acknowledged the U.S. Supreme Court’s factors from the 2020 decision in County of Maui v. Hawaii Wildlife Fund and added a new factor – the design and performance of a system or facility. EPA’s guidance attempts to clarify County of Maui but leaves open many questions as to how the factors will be applied in permitting, enforcement, and citizen suits. EPA is accepting comments on the draft guidance through January 12, 2021.

Under the Clean Water Act, polluted water that is discharged to surface waters (rivers, creeks, wetlands) from a point source must be permitted through the NPDES program. It has long been an open question whether pollutants discharged from a point source to groundwater require an NPDES permit.

The U.S. Supreme Court answered that question in part in 2020 in County of Maui. The Court found that when pollutants are discharged to groundwater from a point source (a well, for example) which eventually discharges to surface water, an NPDES permit is required if the discharge is the “functional equivalent” of a direct surface water discharge. The Court’s decision identified seven factors “that may prove relevant (depending upon the circumstances of a particular case):”

1. transit time,
2. distance traveled,
3. the nature of the material through which the pollutant travels,
4. the extent to which the pollutant is diluted or chemically changed as it travels,
5. the amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point source,
6. the manner by or area in which the pollutant enters the navigable waters, and
7. the degree to which the pollution (at that point) has maintained its specific identity.

The Court emphasized that “[t]ime and distance will be the most important factors in most cases, but not necessarily every case.” The Court also left it to the discretion of the EPA, states, and courts to apply the factors fairly.

EPA’s draft guidance initially points out that certain threshold factors are required before application of the functional equivalent test. These include that the discharge of pollutants to groundwater must be from a point source and such pollutants must reach jurisdictional surface water (the threat of a discharge to surface waters is not enough to trigger an NPDES permit).

Once these threshold factors are established, the draft guidance builds on the Court’s seven functional equivalent factors by adding an eighth factor: “the design and performance of the system or facility from which the pollutant is released.” The guidance differentiates discharges that travel through a system “engineered, designed and operated to treat or attenuate pollutants” or uses land and subsurface features (that probably would not need a permit) from discharges with little or no treatment (that might need a permit). By focusing on treatment systems, EPA’s guidance supplements and attempts to inform application of the functional equivalent factors.

EPA’s guidance may limit the facilities required to permit their discharges to groundwater. Facilities with engineered chemical, mechanical, and/or green infrastructure systems to treat discharges to groundwater will be less likely to need permits.

Despite the guidance and potential uncertainty on application of the functional equivalent factors, facility owners and operators carry the burden of seeking out a permit, if one could be required.  Left unanswered by the guidance are the difficult questions around how EPA and states should issue permits for groundwater discharges that are functionally equivalent to point source discharges. Hopefully EPA will provide future guidance or even rulemaking to answer these questions.   

EPA’s guidance and the functional equivalent factors could affect permitting differently, depending on the state where the facility is located. For states like Idaho and Alaska that do not generally permit groundwater discharges, County of Maui and the guidance could increase the number of facilities that must obtain NPDES permit coverage. In contrast, the impact may be less in Washington where groundwater discharges are already regulated under certain general NPDES/state waste discharge permits.

Litigation and the new Biden administration are likely to help determine whether EPA’s guidance holds water and when groundwater discharges must be permitted under an NPDES program.