November 28, 2023

EPA Issues Guidance on Maui Factors

Holland & Knight Energy and Natural Resources Blog
Dianne R. Phillips
Energy and Natural Resources Blog

The U.S. Environmental Protection Agency (EPA) announced release of its Draft Guidance Regarding NPDES Permitting of Certain Discharges through Groundwater to Surface Waters (Draft Guidance) on Nov. 20, 2023, notice of which was published in the Federal Register on Nov. 27, 2023. EPA is seeking public comment on a draft guidance that outlines factors that may be considered when evaluating whether discharges through groundwater may be subject to regulation under the Clean Water Act. Comments will be accepted until Dec. 27, 2023.

By way of background, on April 23, 2020, the U.S. Supreme Court finally issued its decision in County of Maui v. Hawaii Wildlife Fund, 140 S. Ct. 1462 (2020) (Maui). Specifically, the Court resolved the long-standing question of whether discharges of pollutants to groundwater with a direct hydrologic connection to surface water are or should be regulated under the National Pollutant Discharge Elimination System (NPDES) program. The Court held "that the statute requires a permit when there is a direct discharge from a point source into navigable waters or when there is the functional equivalent of a direct discharge," finding "this phrase best captures, in broad terms, those circumstances in which Congress in­tended to require a federal permit" (Maui at 1468). The Court went on to acknowledge the challenges for potential permittees and their counsel as follows:

The difficulty with this approach, we recognize, is that it does not, on its own, clearly explain how to deal with middle instances. But there are too many potentially relevant fac­tors applicable to factually different cases for this Court now to use more specific language. Consider, for example, just some of the 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, (7) the degree to which the pol­lution (at that point) has maintained its specific identity. Time and distance will be the most important factors in most cases, but not necessarily every case. (Maui at 1476-77)

(See "Is a NPDES Permit Needed for Groundwater Discharge? It Depends," Holland & Knight Energy and Natural Resources Blog, for a discussion of the Maui decision and its background).

EPA's Draft Guidance builds upon the Court's suggestion of factors for consideration, emphasizing that site-specific factors will be critical for the analysis. These features may include distance traveled to surface water, depth to groundwater, soil type, subsurface permeability, hydraulic conductivity and other features that affect the fate and transport of pollutants through the subsurface. In addition to transit time and distance traveled, the Draft Guidance identifies plume characteristics as potentially significant factors, including the amount of dispersion and the concentration gradient across the distance traveled.

Procedurally, the Draft Guidance identifies the list of information to be submitted with the permit application to include the following: discharge locations, transit time, distance traveled, flow characteristics, subsurface geology and hydrogeology, pollutant-specific dynamics, treatment technologies and an explanation of the permittee's functional equivalence analysis. EPA also recommends potentially meeting with the permitting authority early in the application process to discuss the site-specific factors.

The Draft Guidance also makes clear that intent and the existence of a state groundwater permitting program are both irrelevant in the analysis. Industrial dischargers will be subjected to potentially duplicative permitting for discharges to groundwater. EPA devotes several paragraphs as to why such state groundwater protection programs are irrelevant to federal Clean Water Act permitting, perhaps in an effort to appease potential permittees now subject to additional permitting requirements. Only time will tell how burdensome such permitting will become.

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