EPA Issues New Draft Guidance on Discharges to Groundwater

In November, the U.S. Environmental Protection Agency (EPA) quietly released draft guidance on when discharges to surface waters via groundwater would require a Clean Water Act section 402 permit (National Pollutant Discharge Elimination System). Regulated entities will need to determine whether a permit is necessary before discharges occur, and EPA will act if unauthorized discharges to waters of the United States (WOTUS) are discovered. This new guidance may impact the common practices of groundwater recharge and reinfiltration. 

The Biden Administration rescinded earlier guidance issued in January 2021 after the U.S. Supreme Court's decision in the County of Maui, Hawaii v. Hawaii Wildlife, 2020.  Comments on the new “Maui guidance” are due December 27, 2023. 

In Maui, the Supreme Court laid out seven factors for permitting authorities to consider whether an addition of pollutants to groundwater is the “functional equivalent” of a direct discharge of pollutants to a WOTUS.  The Supreme Court determined “transit time and distance traveled” to be the most important factors in most cases. The draft guidance briefly discusses how to assess whether a discharge would be considered functionally equivalent and recommended information to include in a NPDES permit application to request coverage for discharges. The guidance further states that “intent” should not be considered, and a state’s existing groundwater protection program is irrelevant to this program.

Some construction contractors install and/or operate systems in which water is intended to filter into the ground, and ultimately into groundwater—such as with green infrastructure and stormwater retention. The earlier 2021 guidance had provided a “design and performance” factor that would help in these instances. However, the Biden Administration removed that factor from consideration.  

Reception of the draft guidance has been mixed. Some critics say it goes too far by using language typically seen in regulatory text and by stretching terms such as “pollutant” to “constituents of those pollutants.” Another criticism is that the guidance lays out a series of potentially expensive, unclear steps to take---any one of which could trigger functional equivalence.  

For more information, please contact Melinda Tomaino at  

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