WASHINGTON — The Supreme Court ruled on Thursday that the Clean Water Act applies to some pollutants that reach the sea and other protected waters indirectly through groundwater.
The case, County of Maui v. Hawaii Wildlife Fund, No. 18-260, concerned a wastewater treatment plant on Maui, Hawaii, that used injection wells to dispose of some four million gallons of treated sewage each day by pumping it into groundwater about a half-mile from the Pacific Ocean. Some of the waste reached the ocean.
Environmental groups sued, calling it “the clean water case of the century.” A ruling in favor of the treatment plant “would open a massive loophole for every polluter in the country to avoid regulation,” David L. Henkin, a lawyer with Earthjustice, said in November.
In the Supreme Court, the Trump administration filed a brief supporting Maui County, which operates the treatment plant, saying that the law does not apply to discharges that travel through groundwater before reaching protected waters.
In a 6-to-3 ruling, the court rejected what it called the extreme positions advanced by the parties and the administration, returning the case to an appeals court for reconsideration under a new standard. But the decision was on balance a victory for environmental groups, as it allowed at least some lawsuits over groundwater discharges.
“This decision is a huge victory for clean water,” said Mr. Henkin, who argued the case on behalf of environmental groups. “The Supreme Court has rejected the Trump administration’s effort to blow a big hole in the Clean Water Act’s protections for rivers, lakes and oceans.”
The Clean Water Act requires “point sources” of pollution to obtain permits for “any addition of any pollutant to navigable waters.” Failing to have a permit can subject polluters to daily fines of more than $50,000.
It was undisputed that the injection wells in Maui were “point sources.” The case turned largely on whether indirect discharges were considered “from” the wells.
When the case was argued in November, the lawyers debated whether, say, whiskey added to punch from a flask could be said to be “from” the original bottle or, indeed, from a barrel in Scotland.
In the decision on Thursday, the justices similarly debated whether a traveler could be said to have simultaneously come from the train station, Baltimore and Europe and whether a recipe calling for adding drippings from meat to gravy made sense when the drippings were collected from a pan.
Justice Stephen G. Breyer, writing for the majority, rejected both sides’ positions in the case as too extreme. The county and the Trump administration had argued that discharges into groundwater were never covered, while environmental groups suing the county said the law applied to discharges that “actually and foreseeably reach navigable surface waters.”
The United States Court of Appeals for the Ninth Circuit, in San Francisco, ruled for the environmental groups, saying the law applied because pollution in the ocean was “fairly traceable” to the wells.
That standard was too broad, Justice Breyer wrote. “Virtually all water, polluted or not, eventually makes its way to navigable water,” he wrote. The question courts should ask, he wrote, was whether “the addition of the pollutants through groundwater is the functional equivalent of a direct discharge from the point source into navigable waters.”
The Ninth Circuit’s approach, he wrote, “would require a permit in surprising, even bizarre, circumstances, such as for pollutants carried to navigable waters on a bird’s feathers, or, to mention more mundane instances, the 100-year migration of pollutants through 250 miles of groundwater to a river.”
But the opposite extreme, as argued by the county and the administration, would allow polluters to evade the law, Justice Breyer wrote. “Why could not the pipe’s owner, seeking to avoid the permit requirement, simply move the pipe back, perhaps only a few yards, so that the pollution must travel through at least some groundwater before reaching the sea?” he asked.
In requiring “the functional equivalent of a direct discharge,” Justice Breyer listed several factors for courts to consider. “Time and distance are obviously important,” he wrote, but he listed five other considerations, too, including the material through which the pollutants travel and whether they are diluted or chemically altered along the way.
“If the pipe ends 50 miles from navigable waters and the pipe emits pollutants that travel with groundwater, mix with much other material, and end up in navigable waters only many years later,” he wrote, “the permitting requirements likely do not apply.”
Justice Breyer’s opinion, which returned the case to the Ninth Circuit for application of the new standard, was joined by Chief Justice John G. Roberts Jr. and Justices Ruth Bader Ginsburg, Sonia Sotomayor, Elena Kagan and Brett M. Kavanaugh.
In dissent, Justice Clarence Thomas, joined by Justice Neil M. Gorsuch, said the law applied “only when a point source discharges pollutants directly into navigable waters.”
In a separate dissent, Justice Samuel A. Alito Jr. wrote that the majority opinion “makes up a rule that provides no clear guidance and invites arbitrary and inconsistent application.”
“The court,” he wrote, “adopts a nebulous standard, enumerates a non-exhaustive list of potentially relevant factors, and washes its hands of the problem.”