This educational guide is based on the linked primary sources. It is not a Court publication, is not affiliated with the Court, and is not legal advice.
In brief
Overview
According to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), the case concerns whether releases from Maui’s underground injection wells are regulated as point sources under the Clean Water Act.
According to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), the dispute centers on how the Clean Water Act’s point‑source program interacts with state nonpoint‑source regulation for groundwater discharges.
Background and question before the Court
According to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), petitioner argues that the Clean Water Act defines a point source as a “discernible, confined, and discrete conveyance,” and that groundwater, being diffuse, is a nonpoint source.
According to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), the core legal question is where the line falls between the federal point‑source program and the state nonpoint‑source program for groundwater that eventually reaches navigable waters.
What each side argues
Petitioner Position
According to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), groundwater is a nonpoint source.
According to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), according to Petitioner (Elbert Lin), the Clean Water Act defines a point source as a discernible, confined, and discrete conveyance.
Respondent Position
According to Mr. Henkin, the Clean Water Act prohibits unpermitted additions of pollutants to navigable waters from any point source, and the statute does not limit the prohibition to “direct” discharges.
According to Mr. Henkin, Congress did not expressly exempt groundwater discharges that reach navigable waters, indicating that such discharges fall within the Act’s scope.
According to Mr. Henkin, the respondent’s test focuses on a “direct hydrologic connection,” which aligns with the EPA’s historic approach before its 2020 policy change.
What happened at oral argument
Chief Justice Roberts asked whether any small amount of groundwater is enough to break the chain of causation for a point‑source violation.
According to Justice Sotomayor, justice Sotomayor inquired about the distinction between groundwater and land in the context of the Clean Water Act.
Justice Kavanaugh asked why Congress, despite debating groundwater regulation, rejected proposals to exempt groundwater from the Act.
Justice Ginsburg asked whether the Fourth Circuit’s “fairly traceable” test is being advanced.
What the Court decided
Why it matters
The case addresses whether groundwater discharges that eventually reach navigable waters are subject to the Clean Water Act’s point‑source permitting regime.
Terms to know
- point source
- A point source is a discernible, confined, and discrete conveyance of pollutants.
- nonpoint source
- Groundwater is characterized as a nonpoint source because it diffuses through the ground rather than flowing through a discrete conveyance.
Primary sources
Read the source materials on the official site or open the immutable repository copy used for this guide.
- c465ff21ad0e92cfdeda-r1-4fbfc238bdfc0be9.pdforal argument transcript
Guide generated September 27, 2026. Automated validation accepted this version.