The Supreme Court ruled that the Clean Water Act (CWA) requires the federal government to regulate some groundwater pollutants that can make it into navigable waters, such as oceans, rivers and streams.
The law requires those who discharge pollutants into navigable waters from pipes or wells to obtain a federal permit. The discharge of polluted water into the ground, rather than directly into nearby waterways, does not relieve an industry of complying with the CWA.
The decision came in a closely watched case about the County of Maui, which owns and operates four wells at the Lahaina Wastewater Reclamation Facility, the principal wastewater treatment plant for West Maui. The wells receive approximately 4 million gallons of sewage per day from a collection system that serves about 40,000 people, according to the county. The case sought to determine whether a sewage treatment plant needs a federal permit when it sends wastewater deep underground, instead of discharging the treated flow directly into the Pacific Ocean.
The 9th US Circuit Court of Appeals held that the county violated the CWA because it hadn't obtained proper permits and the court said that the law applied to pollutants from the well that had made its way to the ocean via groundwater.
Permits will be required for the discharge of pollutants that reach navigable waters via groundwater if the discharge is either "direct" or the "functional equivalent" of direct from the source, according to the court.
"Entities like water treatment authorities that need to know whether they must get a permit are left to guess how this nebulous standard will be applied," said Justice Stephen Breyer, who penned the 6-3 opinion.