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U.S. 9th Circuit Court of Appeals: Municipally-owned wastewater injection wells require federal permit

On February 1, the U.S. Court of Appeals for the 9th Circuit upheld a lower court's decision in Hawaii Wildlife Fund v. County of Maui, finding wastewater injection wells can be a regulated pollution source under the Clean Water Act (CWA). By ruling underground wells are “point sources” for pollution, and thus require a permit for discharge, the 9th Circuit Court’s decision may have a significant impact on both public and industrial underground injection wells, as well as municipally-owned wastewater and stormwater management facilities, especially those using water storage systems. To comply with the ruling, Maui County estimates the county will be responsible for $2.5 million in upgrades, plus additional civil penalties.

The case in question involves Maui County, Hawaii’s practice of injecting millions of gallons of treated sewage wastewater into four underground wells. The county has been using this process since the mid-1970s and previously had not been required to obtain a CWA permit.

However, environmental groups challenged this approach, arguing the county should be required to obtain a CWA National Pollution Discharge Elimination System (NPDES) permit since the discharge, through groundwater, ultimately runs into the Pacific Ocean. Groundwater has historically not been regulated by the CWA, leaving the responsibility to the states.

Maui County argued the discharges were not regulated because they were not released directly into the ocean. However, the environmental groups performed a dye test indicating that, even though the wastewater was injected into groundwater, the injections eventually reached the ocean after nine months.

The Court of Appeals decision upheld a 2015 decision by the U.S. District Court for the District of Hawaii, ruling the county does in fact need to obtain an NPDES permit. In its decision, largely based on the “conduit theory,” the court stated that because the discharge has the potential to reach the Pacific Ocean, it is the “functional equivalent” of a direct discharge into a navigable water regulated under the CWA.

NACo filed an amicus brief in this case in favor of the County of Maui. NACo will continue to monitor developments surrounding the case, and will continue working to ensure the needs and interests of America’s counties are considered in any final decision.

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