U.S. EPA issues guidance memo regarding discharges to groundwater

The U.S. Environmental Protection Agency (EPA) has recently issued a draft guidance memo on the Supreme Court of the United States (SCOTUS) decision on the County of Maui v. Hawaii Wildlife Fund case. The guidance memo, which is on 30-day public notice as of December 10, covers the issue of discharges to groundwater and whether or not a National Pollutant Discharge Elimination System (NPDES) permit is required for a facility with such a discharge. When finalized, the memo will help the regulated community and permit authorities to incorporate the SCOTUS’s decision into NPDES permits. With the upcoming change in administrations, it is uncertain if or when new guidance will be issued to rescind or supersede this proposed language.

The memo reiterates the Maui decision’s declaration that there must be an actual discharge of pollutants from a point source to a water of the United States for a permit to be required. A mere allegation in public comments, without supporting evidence, is not enough to trigger a requirement for an agency to investigate. The memo states that “only a subset of discharges of pollutants to groundwater that ultimately reach water of the United States are the ‘functional equivalent’ of a direct discharge.” The memo also sets out one additional factor to consider if a discharge to groundwater is the “functional equivalent” of a direct discharge to a water of the United States—“the design and performance of the system or facility from which the pollutant is released.” 

Click here to read the EPA’s guidance memo, and please contact Tom Holstrom ( or Rob Morrison ( if you have questions about the Maui decision or NPDES permitting.


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