Choppy Waters Ahead - NPDES Permitting for Discharges through Groundwater

January 11, 2021
Brenda H. Gotanda, Esq. and Megan A. Elliott, Esq.
MGKF Special Alert - Federal Forecast 2021

The U.S. Supreme Court, in its groundbreaking decision last year in County of Maui, Hawaii v. Hawaii Wildlife Fund, 140 S. Ct. 1462 (2020), ruled that the Clean Water Act (CWA) requires a permit for a point source discharge through groundwater to navigable waters under certain circumstances and it established a new standard likely to see significant interpretation by regulatory authorities, permit writers, and courts in the year ahead.

In the Maui case, the Court held that a permit issued under the CWA National Pollutant Discharge Elimination System (NPDES) program is required for a discharge originating from a point source that is conveyed to navigable waters by a nonpoint source such as groundwater “if the addition of the pollutants through groundwater is the functional equivalent of a direct discharge from the point source into navigable waters.” Id. at 1468. In its ruling, the Court focused on both the statutory intent and the statutory language that the pollutant must be “from” a point source. It held that the intent of the CWA was to provide federal regulation of sources of pollutants to navigable waters, while preserving longstanding state regulatory authority over groundwater and other non-point sources of pollution. Whether pollutants arriving at navigable waters after traveling through groundwater, or other indirect pathways, are deemed to be “from a point source” and require an NPDES permit, the Court ruled, will depend upon how similar to (or different from) they are to a direct discharge to navigable waters.

Recognizing the potential difficulty in applying this new, somewhat amorphous, standard, the Court in Maui provided a non-exclusive list of seven factors that may be relevant in making permitting determinations. Those factors include: (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 has maintained its specific identity at the point of discharge. The Court noted that these factors may need to be weighted differently in different cases and that other factors may also apply depending upon the circumstances.

Regulatory agencies are now beginning to interpret and apply the new standard and the functional equivalent factors. On December 10, 2020, EPA published in the Federal Register, with a 30-day public comment period, a draft guidance document on how to apply the Maui decision’s functional equivalent analysis within the existing permitting framework to discharges reaching navigable waters through groundwater. The draft guidance, intended to clarify the analysis for the regulated community and permit writers, reviews basic permitting principles and adds a new factor to consider, but does not provide much additional detail with regard to the seven functional equivalent factors. It does note, however, that what happens to a discharged pollutant over the time and distance traveled to the navigable waters is critical to the functional equivalent analysis and that the science (e.g., characteristics of the pollutant itself and the nature of the subsurface aquifer and hydrogeology) informs those factors. It adds that there must be an actual, not potential, discharge from a point source and that not all discharges to groundwater that reach navigable waters will be the functional equivalent of a direct discharge.

The new factor to consider in the functional equivalent analysis, identified by EPA in the draft guidance, is the design and performance of the system or facility from which the pollutant is released. EPA states that this type of information is important, relevant, and routinely considered by permitting agencies. Further, it adds that the design and performance of a system or facility can affect or inform all of the other Maui factors. For example, a facility may be designed to slow the transit time of a pollutant or increase the distance it must travel to a navigable water. Likewise, the design may “promote dilution, adsorption or dispersion of the pollutant, thereby affecting the extent to which the pollutant is chemically changed, the amount of pollutant entering the water of the United States relative to the amount of the pollutant that leaves the point source, and the degree to which the pollutant has maintained its specific identity at the point it reaches a water of the United States.” (Draft Guidance, p.7) 

The close of EPA’s public comment period on the draft guidance on January 11, 2021 will occur prior to the inauguration of President-Elect Biden. Whether the Trump Administration intends to finalize the draft guidance before it leaves office remains an open question. We do anticipate, however, that a Biden Administration will likely revisit this guidance and interpretation as it begins to implement its own regulatory priorities.

We also expect to see, in the year ahead, further refinement of the functional equivalent analysis through state level permitting guidance, as well as court decisions applying the standard in individual cases. In the interim, facilities with existing discharges to groundwater that may reach navigable waters should consider evaluating available information regarding their discharge against the Maui functional equivalent factors to assess potential risk that the permitting agency may now require a permit even if one was not previously required by the agency.