EPA Seeks Comment on Possible Regulation of Groundwater Discharges

The U.S. Environmental Protection Agency (EPA) recently requested public comments on whether pollutant discharges that reach “waters of the United States” are subject to regulation under the Clean Water Act (CWA) and require National Pollutant Discharge Elimination System (NPDES) permits. This announcement comes on the heels of a recent Ninth Circuit decision finding that certain underground wastewater discharges in Hawaii required permits under the Clean Water Act.

While the Clean Water Act does not expressly give the EPA regulatory authority over groundwater, in the past these situations have generally been evaluated by the EPA on a case-by-case basis. The primary issue has centered around whether the pollutants discharged into groundwater eventually reach jurisdictional waters of the United States.  The EPA has never definitively stated that CWA permits are required for pollutant discharges to groundwater, but has indicated in the past that pollutants discharged from point sources to jurisdictional surface waters that occur via groundwater or other subsurface flow that has a direct hydrologic connection to the surface water may require CWA permits.

The EPA now appears to be taking a more structured approach that contemplates a new rulemaking on the topic. Specifically, the agency seeks comment on whether subjecting discharges to groundwater to CWA permitting is “consistent with the text, structure, and purposes of the Clean Water Act,” and if so, “whether those releases would be better addressed through other federal authorities as opposed to the NPDES permit program.”

In the request for comment, the EPA also acknowledges that discharges to groundwater are currently regulated by the federal Safe Drinking Water Act’s Underground Injection Control program, as well as by state regulatory programs.

While the EPA has not said what it will do with comments submitted in response to its request, they are likely to be used to inform either a new rulemaking or administrative guidance on this issue. It is also possible that comments will be used to inform the ongoing rulemaking associated with the Trump Administration’s planned replacement for the “Clean Water Rule.” In any event, any new rulemaking or guidance in this area could impact the many industries that discharge to groundwater including mining, oil and gas, wastewater disposal, and CO2 storage.

Affected companies or industries should consider responding to the EPA’s request for comments by May 21, 2018.