Federal court rules LA County liable for stormwater pollution

A concrete channel of the Los Angeles River. 

A federal appeals court Thursday issued an opinion that Los Angeles County is liable for excessively high levels of stormwater pollution in a long-running lawsuit filed by environmental groups against the county.

The Santa Monica Baykeeper and the National Resources Defense Council sued the county in 2008 over pollution that they said violated storm-water permits in the Los Angeles and San Gabriel rivers.

County officials argued that, because other cities discharge polluted runoff upstream from monitoring sites, the county is not primarily to blame.

The U.S. 9th Circuit Court of Appeals, however, ruled in its opinion that the county is still liable for any high pollution levels detected at monitoring stations.

Acceptance of the county’s interpretation of requirements would lead to “an unreasonable result,” the panel said. 

“Under the County Defendant’s reading of the Permit, individual Permittees could discharge an unlimited amount of pollutants…but never be held liable for those discharges based on the results of the emissions monitoring, even though that monitoring is explicitly intended to assess whether Permittees are in compliance,” the opinion said.

Now the case will return to the federal district court to determine how the county will fix the violations, the Los Angeles Times reported.

In 2011, the appeals court ruled that the county was liable for river pollution. The county then appealed the case to the U.S. Supreme Court, which ruled in January that the county is liable for discharges of polluted water from the county-controlled concrete channels, where monitors are located, to downstream portions that lack concrete linings.

Both the Los Angeles and San Gabriel rivers drain polluted water into coastal waters, including the Santa Monica Bay, which can cause residents and tourists to become ill from exposure to polluted water.

Stormwater becomes polluted by contaminants, such as sediments, trash, used motor oil, pesticides and raw sewage, in urban environment before making its way to storm drains and sewers and runoff into other bodies of water, according to the opinion. The panel said that stormwater runoff is “one of the most significant sources of water pollution in the nation.”