## Facts

- The County of Maui operated the Lahaina Wastewater Reclamation Facility, which collected and partially treated sewage.
- The facility injected approximately 4 million gallons per day of treated effluent into the ground through four injection wells.
- The injected effluent traveled through groundwater approximately a half mile and entered the Pacific Ocean near Kahekili Beach via submarine springs.
- Tracer dye studies and monitoring data linked pollutants in the coastal ocean waters to effluent injected from the wells.
- Environmental organizations sued, alleging the County discharged pollutants to navigable waters without a Clean Water Act NPDES permit.
- The district court granted summary judgment to plaintiffs, ruling the discharge was functionally one into navigable waters and rejecting the County’s fair-notice defense.

## Issues

1. Whether the County’s injection wells qualify as Clean Water Act “point sources,” and whether injecting treated effluent into groundwater that ultimately reaches the ocean constitutes an unpermitted discharge to “navigable waters.”
2. Whether Clean Water Act liability requires the point source to convey pollutants directly to navigable waters, or whether indirect conveyance through groundwater may suffice.
3. Whether injections into wells are exempt from NPDES permitting due to regulation under other statutory programs (e.g., underground injection control).
4. Whether due process barred liability because the County lacked fair notice that an NPDES permit was required.

## Decision

- The Ninth Circuit affirmed summary judgment for plaintiffs.
- The court held the County’s four discrete injection wells were “point sources” under the Clean Water Act.
- The court held the Clean Water Act does not require the point source itself to deliver pollutants directly to navigable waters.
- The court applied a standard requiring that pollutants be fairly traceable from the point source to navigable waters, that the discharge be functionally equivalent to a discharge into navigable waters, and that the pollutant levels reaching navigable waters be more than de minimis.
- The court rejected the County’s argument that well injection was exempt from NPDES permitting.
- The court held the statutory and regulatory framework provided fair notice sufficient to satisfy due process.

## Legal Principles

- A “well” can be a Clean Water Act point source when it is a discernible, confined, and discrete conveyance from which pollutants are discharged.
- Clean Water Act liability may attach where pollutants are added to navigable waters from a point source even if the pollutants travel through groundwater before reaching navigable waters.
- Under the Ninth Circuit’s test in this case, an unpermitted discharge exists when pollutants are (1) discharged from a point source, (2) fairly traceable to navigable waters in a manner functionally equivalent to a discharge into navigable waters, and (3) more than de minimis upon reaching navigable waters.
- Regulation under other environmental programs does not categorically displace NPDES permitting where the statutory elements of a point-source discharge to navigable waters are met.
- Due process is satisfied when the Clean Water Act and related authority provide reasonable notice that discharges traceable to navigable waters may require an NPDES permit.

## Conclusion

The Ninth Circuit held the County violated the Clean Water Act by injecting treated effluent from point-source wells into groundwater that conveyed pollutants to the Pacific Ocean in more-than-de-minimis amounts, and it affirmed that an NPDES permit was required despite the indirect pathway and despite the County’s fair-notice and exemption arguments.


Hawaiʻi Wildlife Fund v. County of Maui, 886 F.3d 737 (9th Cir. 2018)