Ledyard King and Richard Wolf

USA TODAY

WASHINGTON – The Supreme Court agreed Tuesday to decide if contamination of groundwater that seeps into rivers, lakes and oceans violates the Clean Water Act.

Dumping pollutants directly into navigable bodies of water is prohibited by the 47-year-old law, but it is less clear about indirect sources.

Last year, the U.S. Court of Appeals for the Ninth Circuit ruled that Hawaii's Maui County violated the law by injecting treated sewage from a wastewater treatment plant into the groundwater, some of which enters the Pacific Ocean. The high court will hear the county's appeal next fall.

"If the Supreme Court reverses the lower courts’ decisions, chemical plants, concentrated animal feeding operations, oil refineries, and other industrial facilities would effectively have free rein to discharge pollutants indirectly into the nation’s waterways without Clean Water Act permits," the environmental group Earthjustice warned Tuesday.

The U.S. Court of Appeals for the Fourth Circuit came to a similar conclusion last year in a South Carolina case involving an underground pipeline that burst in 2014, spilling hundreds of thousands of gallons of gasoline. Some of the fuel seeped into nearby rivers, lakes, and wetlands, including the Savannah River.

However, the U.S. Court of Appeals for the Sixth Circuit did not take the same view in a Kentucky case, in which pollutants from coal ash retention ponds seeped into groundwater that fed local waterways. The court said only pollutants added directly to navigable bodies of water were regulated under the law.

The Supreme Court's decision to hear the case comes about two months after the Trump administration announced it was rolling back an Obama-era regulation that has become a rallying cry for farmers and property-rights activists opposed to federal overreach.

Undoing a regulation President Donald Trump has called "a massive power grab," the new proposal would ease Washington's oversight of small bodies of water. It would replace an Obama administration regulation, known as the Waters of the United States rule, that expanded federal protections to smaller rivers and streams.

Andrew Wheeler, the Environmental Protection Agency's acting administrator, said states should oversee most ditches, land that fills with water when it rains, certain wetlands that have been used to grow crops, storm water control ponds, and water and wastewater treatment systems.

Additionally, groundwater would not be federally protected, a category Wheeler said never should have been included.

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