County of Maui v. Hawaii Wildlife Fund
The Supreme Court ruled that a Hawaii county's wastewater facility may need a federal Clean Water Act permit even though its treated sewage travels through groundwater — not a direct pipe — before reaching the Pacific Ocean, adopting a new 'functional equivalent of a direct discharge' standard.
The decision charts a middle course between two extremes: it rejects a rule that would require permits whenever any pollution can be traced to a facility, but also rejects a blanket exemption for anything that passes through groundwater, leaving courts and the EPA to develop case-by-case guidance.
“We hold 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.”
The Court's core holding establishing the new standard for when groundwater-conveyed pollution requires a Clean Water Act permit.
How it got here: A federal district court ruled for the environmental groups; the Ninth Circuit affirmed using a "fairly traceable" standard; Maui asked the Supreme Court to hear the case, which agreed because different federal appeals courts had adopted conflicting tests.
The Case in Depth
What happened
Maui County's wastewater facility on the island of Maui pumps about 4 million gallons of partially treated sewage each day into four underground wells. The effluent then travels roughly a half mile through groundwater and flows into the Pacific Ocean. A group of environmental organizations sued, arguing the county needed a federal Clean Water Act permit because it was discharging pollutants into navigable waters — the ocean — without one.
The question before the Court
Does the Clean Water Act require a federal pollution permit when wastewater pumped into the ground travels through groundwater before reaching the ocean?
The Court's answer
Partly — the Court ruled that the Clean Water Act requires a permit when pollution moving through groundwater amounts to the "functional equivalent of a direct discharge" into navigable waters. This is neither an automatic yes (whenever pollution is traceable back to a facility) nor an automatic no (whenever any groundwater lies between the pipe and the water).
The key factors are time and distance: a pipe that discharges just a few feet from the ocean will likely need a permit; one that releases pollutants 50 miles away, with pollutants taking many years to arrive, likely will not. Six additional factors — including how much the pollutant changes in transit and how much ultimately reaches navigable waters — may also matter. The Court sent the case back to the lower courts to apply this new standard to Maui's specific facts.
Curious how the Court got there? See the step-by-step legal reasoning →
Why it matters
Wastewater treatment plants, mines, and industrial facilities that inject or discharge pollutants near rivers, lakes, or coastal waters may need federal Clean Water Act permits even when the pollution travels through groundwater first. The ruling implicates hundreds of thousands of underground injection wells and millions of septic systems, though how broadly it applies will depend on future court decisions and EPA guidance.
What changes now
The case returns to the Ninth Circuit to apply the new "functional equivalent of a direct discharge" test to Maui's specific facts — principally whether the half-mile groundwater journey to the ocean is close enough to a direct discharge to require a permit. Lower federal courts nationwide will also need to work out how the multi-factor test applies to other indirect discharges. The EPA can issue rules, general permits, and guidance to bring more consistency to the standard going forward.
What this does not decide
The Court explicitly declined to set firm time or distance limits for "middle" cases and acknowledged its standard does not clearly resolve those situations. The ruling does not determine whether Maui's facility actually needs a permit — that question goes back to the lower courts — and it does not address the permitting status of the over 20 million septic systems in American homes.
Concurrences and dissents
Concurrence — Justice Kavanaugh
Justice Kavanaugh joined the majority in full but wrote separately to make three points: the Court's ruling is consistent with Justice Scalia's plurality opinion in Rapanos v. United States; the vagueness in the resulting standard flows from Congress's own ambiguous text, not from the Court's reasoning; and he pushed back on Justice Thomas's claim that the majority gave no guidance on which factors matter most, since the Court expressly identified time and distance as the most important factors in most cases.
Dissent — Justice Thomas
Justice Thomas, joined by Justice Gorsuch, argued that a permit is required only when a point source discharges pollutants directly into navigable waters — nothing more. He focused on the word 'addition,' reasoning that when pollutants pass through groundwater before reaching the ocean, the navigable water is augmented from the groundwater, not from the original pipe. He would have reversed outright without a remand, and criticized the majority's seven-factor test as giving nearly no administrable guidance.
Dissent — Justice Alito
“If the Court is going to devise its own legal rules, instead of interpreting those enacted by Congress, it might at least adopt rules that can be applied with a modicum of consistency.”Justice Alito's opening objection that the majority's multi-factor test provides no clear or consistent guidance.
Justice Alito argued that the statutory text compels a choice between only two readings of 'from': the pollutant originated from the point source, or it was discharged directly from the point source into navigable waters. The second is the better reading. He criticized the majority's 'functional equivalent' test as having no basis in the statute's text, providing no clear meaning, and leaving dischargers, regulators, and judges to guess at its application case by case.
How the Court got there
The legal reasoning, step by step
- The case turns on the Clean Water Act's requirement that a permit be obtained for any 'addition of any pollutant to navigable waters from any point source.' The central interpretive fight was over the word 'from': can a facility be the origin of pollution that reaches navigable waters only after traveling through groundwater?
- The Court first rejected the Ninth Circuit's 'fairly traceable' standard — which would require a permit whenever pollution can be scientifically tracked from a facility to a waterway — because modern science can trace pollutants over 250 miles of groundwater across 100 years, an absurd sweep Congress never intended. The Act's structure also shows Congress deliberately left groundwater regulation primarily to the States.
- The Court next rejected the opposite extreme: Maui's argument that any amount of groundwater between the pipe and the water breaks the connection entirely. That rule would let any polluter simply move a pipe a few yards back from the shoreline to dodge the permit requirement entirely — a massive loophole in one of the Act's key regulatory innovations.
- The Court also declined to follow the EPA's 2019 Interpretive Statement, which read the Act to exempt all discharges to groundwater from permitting. That reading is hard to square with the statute's use of 'any addition,' the inclusion of 'wells' in the definition of 'point source,' and a provision allowing the EPA to delegate permitting authority to states only if they control disposal 'into wells.'
- Reading the statute's text, structure, and history together, the Court held that a permit is required when an indirect discharge through groundwater is the 'functional equivalent of a direct discharge' — meaning it reaches navigable waters through roughly similar means as a pipe emptying directly into them. Time and distance are the most important factors in most cases; others include how much the pollutant is diluted or chemically changed and how much of it actually arrives.
- The Court acknowledged this standard does not draw bright lines for middle cases, but noted the EPA has successfully applied permitting requirements to some groundwater-connected discharges for over 30 years with no evidence of unmanageable expansion, and that the EPA, States, and lower courts can develop more specific guidance through rules and individual decisions.
Doctrinal impact
Cases affected by this decision
Reaffirms Rapanos v. United States (547 U. S. 715)
The Court builds on Justice Scalia's Rapanos analysis that the Act does not require pollutants to reach covered waters directly from a point source.