Groundwater Discharges Under the Clean Water Act

Suppose you operate a facility that pumps treated wastewater into the ground, and the wastewater travels to a nearby ocean through a hydrological connection. Do you need a Clean Water Act discharge permit?

In April 2020, the U.S. Supreme Court considered and answered this question with an indefinite “probably.” In County of Maui v. Hawai’i Wildlife Fund, the Court held that indirect discharges of pollutants may be subject to Clean Water Act permitting requirements if they are the “functional equivalent” of a direct discharge.

This was neither the analysis nor outcome that many in the regulated community expected. Many saw County of Maui as an opportunity to clarify the Clean Water Act’s scope. Unfortunately, the Supreme Court did not seize that opportunity. Instead, the Court’s most meaningful decision regarding the Clean Water Act in decades has created uncertainty and confusion, created the need for more litigation, and increased potential liability and costs for activities like green infrastructure, septic tanks, treatment ponds, and groundwater recharge projects; which the Clean Water Act did not regulate previously under the permitting program.

Background

Almost 50 years ago, Congress enacted the Clean Water Act. At its core, the Act requires a permit when you add a pollutant to a navigable water from a point source. A “point source” is a discernible, confined, and discrete conveyance, like a pipe or ditch. The classic example of a regulated point source is a pipe that directly discharges pollutants into a navigable river. In that scenario, the discharges require a National Pollutant Discharge Elimination System (NPDES) permit.

But what if that pipe is upland and several miles from the river? If pollutants from that upland pipe eventually reach the navigable river, does the Clean Water Act require an NPDES permit? These questions were posed in the County of Maui case.

In County of Maui, the County’s wastewater reclamation facility pumped treated water into the ground through four injection wells. Once discharged, the wastewater migrated with groundwater for about a half mile to the Pacific Ocean. Environmental groups filed a citizen suit under the Clean Water Act that claimed the indirect discharges from the County’s wells into the ocean required an NPDES permit.

The Ninth Circuit Created a ‘Fairly Traceable’ Test…

Before reaching the Supreme Court, the Ninth Circuit held that pollutants indirectly discharged to navigable waters require an NPDES permit if the pollutants discharged are “fairly traceable” from the receiving navigable water to the point source. In effect, the “fairly traceable” test looks at the water for more than de minimis pollutants and traces the pollutants back from the navigable water to their point source.

…Which the Supreme Court Rejected

The Supreme Court rejected the “fairly traceable” test. In a 6-3 decision written by Justice Stephen Breyer, the majority found this test expanded the U.S. Environmental Protection Agency (EPA) authority beyond what Congress intended. For example, the test would allow EPA to assert permitting authority over discharges that could be more than 50 miles from the nearest navigable water.

But concern for expanding EPA authority did not lead the Court to hold that the Act prohibited only the discharge of pollutants directly from point sources to navigable waters. Instead, it led to a concern about loopholes.

Recall the classic example of a pipe directly discharging into a navigable river. What if a discharger cuts the pipe off just before the river? The pipe now discharges to the river bank, not the river. The discharge pollutes the river, but not directly. If the Act did not regulate that discharge, the majority explained, it would create a loophole that undermines the Act’s purpose of protecting the integrity of our nation’s waters. And thus, the surprise: The majority, joined by Chief Justice John Roberts and Justice Brett Kavanaugh, favored the Act’s purpose over the statute’s text.

The ‘Functional Equivalent’ Test

The Court acknowledged that the Act does not regulate all indirect discharges. But that does not mean that it regulates none. According to Justice Breyer, “there is quite a gap between ‘not all’ and ‘none.’”

The majority balanced these competing concerns and held that the Act “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.” Unfortunately, this raises more questions than it answers.

What is the “functional equivalent of a direct discharge”? Does it mean only an indirect discharge from a pipe that is a few feet from a navigable water? Or could it include pipes or wells that are farther away? Does it include settling ponds that leach to groundwater that travels some distance and then discharges to a river?

The Supreme Court offered some guidance to determine functional equivalence by identifying seven factors that regulators, the regulated community, and district courts may consider when evaluating indirect discharges. These include:

• transit time
• distance traveled
• the nature of the material through which the pollutant travels
• the extent to which the pollutant is diluted or chemically changed as it travels
• the amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point source
• the manner by or area in which the pollutant enters the navigable waters and
• the degree to which the pollution (at that point) has maintained its specific identity. 

But this is not an exhaustive list. Instead, this represents “just some of the factors that may prove relevant.” So while the majority considers time and distance the most important, it acknowledged that other, unlisted factors may be relevant.

Uncertainty Abounds

With an uncertain number of factors and uncertainty in how the EPA or courts will weigh each in different contexts, the County of Maui case invites multiple approaches to Clean Water Act regulation. Rather than provide clarity and uniformity, the case prescribes uncertainty.

Take the wastewater reclamation facility in County of Maui, which operated for over three decades without an NPDES permit before it received a notice of violation letter. Throughout those decades, little changed in either its discharges or the Act’s text.

Technology, however, changed. We can now better trace pollutants through diffuse media like groundwater. So rather than adhere closely to the Act’s text, the majority provided a flexible interpretation that accounts for technology gains — but at the expense of a bright line test. Without a clear test by which regulated entities may conform their conduct, the Court has left undecided the extent of activities the Act regulates. Indeed, at the time of this article’s writing, it remains unclear whether the facility in County of Maui requires an NPDES permit. It may, but not necessarily.

How then can entities know whether the Act applies to them? Often, they must enlist a hydrologist to evaluate their activities given the “functional equivalent” factors. This is costly, and presents a serious dilemma: Will they incur the expense of hiring experts to determine whether the Act applies (and the expense of applying for a permit)? Or will they forgo that expense and risk a regulator or citizen suit enforcement action? It’s a Morton’s fork forced on the regulated community.