Supreme Court Ruling Finds Old, New Middle Ground on Clean Water Act’s Application to Groundwater

In 1972, the U.S. Clean Water Act (CWA) created a permit system for point source discharges to navigable waters of the United States – rivers, lakes, and coastal waters – with the goal of restoring and protecting their water quality. Typically, these permits are issued by the U.S. EPA or through state agencies to dischargers of wastewater, e.g., from urban and industrial wastewater treatment plants and to other dischargers of potentially contaminated water that reach streams by a pipe or similar conveyance. The goal was to provide some degree of regulatory oversight over such discharges. In California, the State Water Resources Control Board implements the federal Clean Water Act using its authority under the Porter-Cologne Water Quality Control Act (Water Code, §13000 et seq.). Under the CWA, neither EPA nor the states are required to issue permits for pollutant discharges into groundwater or to nonpoint source dischargers.

Last week, the Supreme Court decided on a case involving discharge from a wastewater reclamation facility owned and operated by the County of Maui. In this case, the facility discharged 3 to 5 million gallons of treated wastewater per day into four injection wells about half a mile from the ocean. Recent research showed that much of the injected waste eventually discharges to the ocean. Environmental groups sued the county for not obtaining a CWA permit, arguing that point source discharge of pollutants that eventually reach surface water is governed under CWA. All sides agreed that the case at hand involved a point source of pollutant discharge and that the pollution eventually reached the ocean. The disagreement was whether the CWA requires the permit only if the pollutant discharge is directly into surface water, as argued by the defendants (a "bright-line test"). Environmental groups argued that even if the pollutant discharge is via groundwater to surface water, the CWA permit must be obtained. The district court and the Ninth Circuit court ruled in favor of the plaintiffs. The Ninth Circuit court held that permits are required when "pollutants are fairly traceable" from the point source to surface water.

In its final 6-3 decision, the Supreme Court majority now rejects both sides' arguments as too extreme and returned the case to the lower courts with further guidance. On the "bright-line test", Justice Breyer, writing for the majority, wrote "we do not see how Congress could have intended to create such a large and obvious loop hole in one of the key regulatory innovations of the Clean Water Act." On the "fairly traceable" approach, the opinion stated that such interpretation "would require a permit in surprising, even bizarre circumstances".

Instead, the Court decision introduces the concept of a "functional equivalent of a direct discharge" as a guideline for when a point source discharge must obtain a permit. It cites the case of an injection well receiving pollutant discharge that then travels a few feet through groundwater into navigable waters as a clear case of "functional equivalent" to direct discharge. But it rejects the notion that such a "functional equivalent" exists in a case with "100 year migration of pollutants through 250 miles of groundwater to a river" and "likely does not apply" if "the pipe ends 50 miles from navigable waters". The Court acknowledges that the concept of "functional equivalence" as the Court's guideline leaves many point source discharges to groundwater somewhere between these extreme cases. It relegates consideration of those cases back to regulators and lower courts, suggesting they consider the various groundwater flow and transport factors underlying individual cases – travel time and distance in particular, but also soils and geology, geochemical reactions, the locations where pollutants subsequently enter navigable waters, and "the degree to which the pollution (at that point) has maintained its specific identity."

Importantly, the majority opinion does not expect a "vastly" expanded scope of the CWA, such that permits would be required, e.g., for the country's 20 million septic systems. It does so in two ways: by emphasizing (and affirming) the long history of CWA implementation, which has, at times, required permits even if pollutant discharge was via groundwater into surface waters, but not under other circumstances. And, secondly, both the majority and dissenting opinions repeatedly underscore the important role and sovereignty of states in regulating discharges to groundwater and nonpoint source pollution (groundwater pollutant discharge to surface water is sometimes considered nonpoint source pollution of surface water).

The decision will not make it easier than in the past for either regulators or lower courts to make their determinations as to whether a point source pollutant discharge to groundwater that eventually affects surface water is subject to a CWA permit. But the decision sides squarely with the use of science. And it shows a remarkable acknowledgement of hydrologic sciences and the interconnectedness of surface water and groundwater: "Virtually all water, polluted or not, eventually make its way to navigable water. This is as true for groundwater." Perhaps this statement missed the nuance that some groundwater, particularly in the western U.S., will instead be pumped by wells onto crops or pulled by plant roots from the water table to be evapotranspired into the atmosphere. But it underscores that the court made its decision knowing and applying hydrologic science. "Given the power of modern science, The Ninth Circuit's limitation, 'fairly traceable', may well allow EPA to assert permitting authority over the release of pollutants that reach navigable waters many years after their release […] and in highly diluted forms.", an application that the justices find inconsistent with the CWA.

The dissenting opinion of Justice Alito rejects the introduction of the "functional equivalence" concept as too vague and inconsistent with the language of CWA. Given the authorities of states on matters of groundwater and nonpoint source pollution, he supports the "bright-line test". But importantly, Justice Alito instead refers to the definition of "point source" as a means to avoid the loopholes cited in the majority opinion as reason to reject the "bright-line test": He points out that, according to CWA, "point source[s] include [….] 'any discernible, confined and discrete conveyance… from which pollutants … may be discharged.' §1362(14)." The opinion continues to describe how the pathway created by pollutant discharge from a pipe onto a beach and ending in the ocean" or many of the cases that trouble the Court" would easily be covered by applying common definitions of "conveyance", "discernable", and "confined". Groundwater hydrologists may further point out something not mentioned and perhaps not considered by Justice Alito: that we do have scientific tools (as referred to by the majority opinion) to similarly describe some groundwater pathways as a conveyance that is indeed discernable and confined, "i.e., held within bounds". So perhaps Justice Alito's argument, from a scientific perspective, would in practice not be substantively different from the scientific criteria that the majority opinion associated with defining "functional equivalent" point source discharge. Such an interpretation would add further support and a consistent angle to the overall spirit of the Court's decision.

The Maui decision is already having a ripple effect in other areas of environmental concern. Environmentalists have long been advocating against the use of coal ash impoundments—open pits for disposal of toxic byproducts left over from burning coal. Many of these byproducts have allegedly moved from these impoundments through groundwater into streams and rivers. Prior to the decision in Maui, power companies argued the CWA permitting program was inapplicable to impoundments. But the Maui decision will likely lend weight to these challenges.

The Maui decision also will likely impact litigation over the federal administration's repeal of the Water of the United States rule, a regulation under the Obama administration which clarified the views of the Environmental Protection Agency and the U.S. Army Corps of Engineers about the reach of the Clean Water Act. In this repeal, this administration specifically stated, in response to commenters, that "A groundwater or subsurface connection could also be confusing and difficult to implement, including in the determination of whether a subsurface connection exists and to what extent." U.S. Army Corps of Engineers and Environmental Protection Agency, The Navigable Waters Protection Rule: Definition of ''Waters of the United States," 85 Fed. Reg. 22,250, 22,313 (Apr. 21, 2020). Promulgated by the agencies before the Maui decision came out, the agencies will likely have to wrestle with the Maui decision in subsequent challenges.

While the decision leaves some previous uncertainty over the interpretation of the CWA, and perhaps adds some, California dischargers are unlikely to face additional regulation under this decision. Under the Porter-Cologne Water Quality Control Act, California already requires permits for discharges to groundwater, even if they don't meet the "functional equivalent" test outlined by Justice Breyer's majority opinion. California regulators may need to adjust their approach to reflect that some of these permits will also serve as CWA permits under the state's authority, but this should not impose significant new burdens on regulated entities. California's robust implementation of a strong groundwater quality regulatory program, implementing state laws (including the Sustainable Groundwater Management Act, SGMA) and other federal laws governing discharge of pollutants to groundwater (Safe Drinking Water Act, Toxic Substances Control Act, Resources Conservation and Recovery Act, state and federal Superfund programs) puts it in an excellent position to have little to worry about a new layer of bureaucracy and restrictions.

The decision's reliance on strong groundwater science marks another significant step in the emerging integration of groundwater and surface water. The California courts and legislature have long regarded surface water and groundwater as legally distinct, but over the last decade that legal fiction has begun to break down. In 2014, SGMA explicitly recognized the relationship between groundwater and surface water, requiring groundwater managers to avoid significant and unreasonable adverse impacts on beneficial uses of surface water. In 2018, a California appellate court ruled that the public doctrine applies to groundwater extraction if it adversely impacts a navigable waterway. This decision validates the hard work of water scientists working to protect critical freshwater systems in the context of integrated watershed and water resources management, including efforts to protect many of these freshwater resources that depend on high quality groundwater discharge. And it reminds us to keep hard at working to achieve the larger vision of the Clean Water Act.

Professors Tai and Harter were both authors of an amicus brief in this Supreme Court case.