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.