Today, the Supreme Court of the United States published its opinion in a case concerning the role of groundwater in the Clean Water Act (“CWA”). The case, Cty. of Maui v. Hawaii Wildlife Fund, — U.S. — (2020), was first filed in 2012 and addressed unpermitted discharges of treated sewage water made by the County of Maui (“County”) into in-ground wells. In its opinion, the Supreme Court found in favor of the defendants and concluded that discharges of pollutants into groundwater require a CWA permit when the discharge is the “functional equivalent” of a direct discharge.

The Clean Water Act & The Conduit Theory

The CWA is the federal statute that governs water pollution. Its purpose is to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters.” 33 U.S.C. § 1251(a). To achieve this purpose, the CWA prohibits the discharge of “any pollutant to navigable waters from any point source” without a permit. 33 U.S.C. § 1362(12). The Act defines “a point source” as “any discernable, confined and discrete conveyance. . .from which pollutants may be discharged,” including any “pipe, ditch, channel, conduit” or “well.” U.S.C. § 1362(14).

Under the CWA, a discharge of a pollutant directly from a pipe or ditch into a navigable water such as the Pacific Ocean without a valid permit would be a violation of the Act. However, this case involved a dispute over whether the unpermitted discharge of a pollutant into a nonpoint source, such as groundwater, which then carries the pollutant to a navigable water would also be a CWA violation. The idea that such a discharge would violate the CWA is known as conduit theory and tends to focus on discharges of pollutants into groundwater. The argument is that if a pollutant is discharged into groundwater which then carries the pollutant and deposits it into a navigable water, the discharge into the groundwater should require a CWA permit as much as if it were discharged into the navigable water directly.

Cty. of Maui Background

The County of Maui owns and operates four wells at the Lahaina Wastewater Reclamation Facility on the island of Maui, Hawaii. The facility functions by gathering sewage from the surrounding area, treating it, and then using the four wells to pump approximately 3 to 5 million gallons of wastewater per day directly into groundwater. From there, the wastewater travels roughly half a mile through the groundwater system before entering the Pacific Ocean.

Hawaii Wildlife Fund and several other environmental groups initially brought suit against the County in 2012, arguing that the discharges violated the CWA because they were unpermitted discharges of pollutants into a navigable body of water. The County defended itself by arguing that the discharges had been made directly into groundwater, not a navigable waterbody, and that the discharges were therefore not governed by the CWA. Both the United States District Court for the District of Hawai’i and the Ninth Circuit Court of Appeals found in favor of the plaintiffs. The Ninth Circuit concluded that the discharges were governed by the CWA because “the pollutants are fairly traceable from the point source to a navigable water such that the discharge is the functional equivalent of a discharge into the navigable water.” According to the Ninth Circuit, the groundwater had served as a conduit to transport the pollutants into a navigable water such that discharging into the groundwater was no different than discharging directly into the Pacific Ocean.

The County appealed the Ninth Circuit’s decision to the Supreme Court. Oral arguments were made before the Court on November 6, 2019. On April 23, 2020, the Court issued its opinion concluding that unpermitted discharges of pollutants into groundwater would violate the CWA if the discharge was the functional equivalent of a direct discharge.

Cty. of Maui Before the Supreme Court

In front of the Supreme Court, the County argued that the permitting requirement of the CWA only applied to discharges that resulted in pollutants entering a navigable water directly from a point source. If a pollutant discharged from a point source traveled any distance through groundwater before reaching a navigable water, the County argued that it did not require a CWA permit. On the other hand, the Hawaii Wildlife Fund argued that the Court should uphold the Ninth Circuit’s opinion and conclude that if a pollutant could be “fairly traced” back to a point source it should be subject to CWA permitting requirements no matter how far it traveled through groundwater to reach a navigable water.

The Court declined to take either approach. While it determined that the County’s argument was too restrictive and read an unintended loophole into the CWA, it also felt that the Ninth Circuit’s interpretation was too broad because it could allow EPA to assert authority over discharges that have only reached a navigable water after traveling vast distances or vast lengths of time.

Having determined that both sides made arguments that were too extreme, the Court concluded 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.” According to the Court, this interpretation best reflects the circumstances in which Congress envisioned the requirement of a federal permit when it passed the CWA.

To determine when a discharge into a nonpoint source is the functional equivalent of a direct discharge, the Court explained that several factors could be considered. It listed a variety potential factors included transit time, distance traveled, nature of the nonpoint source material, extent to which the pollutant becomes diluted, and the amount of pollutant to reach a navigable water. Of these factors, the Court noted that time and distance would be the most important. Additionally, the Court pointed out that specific guidance could be provided by the Environmental Protection Agency (“EPA”) on when a discharge into a nonpoint source would be functionally equivalent to a direct discharge.

Going Forward

Ultimately, the Supreme Court’s opinion in Cty. of Maui v. Hawaii Wildlife Fund is likely to result in some discharges of pollutants into groundwater requiring CWA permits. Although the Court limits the conclusion of the Ninth Circuit which may have resulted in all such discharges being subject to the CWA’s permit requirements, it rejected the County’s argument that all discharges into groundwater were beyond the jurisdiction of the CWA. While the Court concluded that time and distance would be crucial factors in determining which discharges into groundwater would be functionally equivalent to direct discharges, without further guidance it may be difficult to determine precisely which discharges will require permits. In terms of agriculture, this has the potential to affect everything from field tiling systems to manure stored in waste lagoons. At the very least, this is an issue that will be addressed both through regulations and within the court system for years to come, as more specific applications and parameters are identified.

To read the U.S. Supreme Court opinion in Cty. of Maui v. Hawaii Wildlife Fund, click here.

To read U.S. Supreme Court case documents in Cty. of Maui v. Hawaii Wildlife Fund, click here.

To read the Ninth Circuit opinion in Cty. of Maui v. Hawaii Wildlife Fund, click here.

To read the district court opinion in Cty. of Maui v. Hawaii Wildlife Fund, click here.

To read the text of the Clean Water Act, click here.

For more National Agricultural Law Center resources on the Clean Water Act, click here.

For more National Agricultural Law Center articles on Cty. of Maui v. Hawaii Wildlife Fund and the role of groundwater in the CWA, click here or here.