The CWA forbids any discharge of a pollutant from a point source to navigable waters without a NPDES permit. In a 6-3 opinion, the Supreme Court held that a NPDES permit is required when a discharge of pollutants through groundwater to a navigable water is the “functional equivalent of a direct discharge from the point source into navigable waters.”
The case concerned the County of Maui’s wastewater treatment facility, which releases treated wastewater into four underground injection control wells. Wastewater from the wells then travels about half a mile through unconfined groundwater and eventually reaches the ocean, a navigable water subject to the CWA. Environmental groups filed suit against the county, alleging that the county needed an NPDES permit because the county was discharging a pollutant from a point source through groundwater to a navigable water.
All three of the courts to consider this case — the lower District Court, the intermediate Ninth Circuit appellate court, and the U.S. Supreme Court — applied a different legal test to this novel issue. The district court ruled in favor of the environmental groups, concluding that a NPDES permit is required because the discharge is functionally one into navigable water. The Ninth Circuit agreed that the environmental groups should prevail, but reasoned that a NPDES permit is required because the pollutants are fairly traceable from the point source to the navigable water. The Supreme Court formulated its own test — which is now the law of the land — holding that a NPDES permit is required when there is a discharge from a point source directly into navigable waters or when there is the functional equivalent of a direct discharge
The Supreme Court acknowledged the difficulty of determining when a permit is required under this new test, and outlined many factors that may be relevant to determining whether a particular discharge is the functional equivalent of one directly into navigable waters, including:
- Transit time
- Distance traveled
- The nature of the material through which the pollutant travels
- The extent to which the pollutant is diluted or chemically changed as it travels
- The amount of pollutant entering the navigable waters relative to the amount of the pollutant that leaves the point source
- The manner by or area in which the pollutant enters the navigable waters
- The degree to which the pollution (at that point) has maintained its specific identity
Because the District Court and Ninth Circuit did not apply this test in evaluating the facts of this case, the case will return to the District Court for further proceedings consistent with the Supreme Court’s decision.
The League joined a coalition of local agency associations in filing an amicus brief
to the Ninth Circuit Court of Appeal, a letter
in support of the County of Maui’s Petition for Certiorari, and an amicus brief
to the United States Supreme Court in this case.