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500,000-Gallon Sewage Leak in El Sobrante Was 'Preventable'

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A wooded ravine is seen from across a traffic median. Two a-frame signs, one in the foreground and one set in the ravine, read "Danger/Peligro." Sitting inconspicuously beneath the closer a-frame and the median divider is a manhole cover.
The San Pablo Creek in El Sobrante. More than 500,000 gallons of raw sewage leaked from a maintenance hole in El Sobrante, affecting nearby San Pablo Creek. (Courtesy West County Wastewater)

More than 500,000 gallons of sewage spilled from a maintenance hole in El Sobrante, according to a local wastewater treatment agency. The waste leaked into nearby San Pablo Creek.

West County Wastewater (WCW) was alerted to the spill by a nearby resident, who called it in over the weekend. The agency said it has stopped the leak, which they estimate may have lasted up to two weeks.

“It’s really disappointing to have a sewage spill of this magnitude,” said Sejal Choksi-Chugh, director of the pollution watchdog nonprofit San Francisco Baykeeper. “It’s a lot to go unnoticed for almost two weeks.”


According to a WCW press release, the spill was caused by a “blockage of grease and disposable wipes, which should not be flushed down toilets.”

WCW said there’s been no impact to the public, though Choksi-Chugh points out sewage spills from maintenance holes can contain chemicals and pharmaceuticals and can also be dangerous for humans, pets and wildlife.

“A lot of people could come into contact with this sewage water while it’s in the street, and that can cause illness in people, it can cause illness in pets,” she said.

The sewage can also make its way into the San Francisco Bay and affect wildlife there, including fish and birds, she said.

“Right now, there are no reports of any deceased wildlife associated with the incident,” said Eileen White, executive officer of the San Francisco Bay Regional Water Quality Control Board, which is investigating the incident. “That’s what we look for: Are there dead birds? Are there dead fish in the area?”

White said the California Department of Fish and Wildlife is doing a more thorough assessment of the impact on nearby waterways and habitat areas.

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“Unfortunately, where the sewage was coming out was not obvious to people for some time,” White said. “It wasn’t like it was coming out in front of someone’s house.”

She added that once WCW was alerted to the incident, the agency acted immediately to stop the spill.

The spill has been stopped, but is not yet contained, according to WCW. In the meantime, the agency is collecting samples and running tests in the affected areas.

The Contra Costa County Health Department is also investigating potential health impacts from the sewage that leaked into nearby San Pablo Creek.

“While that creek is not a source of drinking water, it is a habitat area and also goes through a residential community, and if anyone would happen to be in contact with the creek, there could potentially be some health issues,” said county Supervisor John Gioia.

Baykeeper’s Choksi-Chugh said sewage spills of this magnitude are more common during heavy rainstorms when there’s a lot of water running through the system. A dry spill of this magnitude, she said, is very rare.

It’s also a reminder of the Bay Area’s aging sewage system, which Choksi-Chugh said dates back more than 60 years.

“[WCW] really should have put this pipe on a maintenance schedule before this spill happened,” she said. “This was a preventable spill.”

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