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Coliform bacteria found in 2 Imperial Beach water samples: water board

E. coli sample triggers boil water advisory for thousands in San Diego County
Posted at 7:26 PM, Aug 25, 2023

IMPERIAL BEACH, Calif. — Thousands of residents are being asked to boil their water for a second night after coliform bacteria was detected in two samples in Imperial Beach and a third test came back E. Coli positive.

California’s water board regulator told 10News investigative reporter Austin Grabish on Friday that it became aware of two coliform positive test results on Monday before a follow up sample taken Wednesday came back E. coli positive.

“The presumption is it's in the water, but that's uncertain at this point,” said Darrin Polhemus, the deputy director of drinking water with the State Water Resources Control Board.

UC San Francisco infectious diseases expert Dr. Peter Chin-Hong said coliform organisms are not necessarily harmful on their own but said they often can serve as a proxy for other dangerous bugs like E. Coli, which is concerning.

“I think until it's conclusively shown that the water supply is safe at this point, particularly if more than one sample is obtained, you should either drink bottled water or boil the water for at least one minute. That's all you need to really kill E. coli,” he said.

California American Water said Friday evening it was waiting for further testing to come in so it could lift the boil water advisory that it said is impacting 17,000 residences and businesses in areas of Coronado, Imperial Beach, San Diego and Chula Vista.

The company’s spokesman Brian Barreto said it was investigating what could have caused the positive E. coli test result and was looking into whether a faucet may be to blame for the scare.

“We do not have any indication that the water in our system is contaminated,” he said while adding he didn’t believe Sunday night’s tropical storm that brought heavy rain to San Diego was to blame.

He added the company had nothing to indicate the test was taken improperly.

“We looked at the protocols that our utility worker went through. We have no indication that there was any sort of challenges, or any mistakes made with the sampling process.”

The County of San Diego estimated over 100,000 people are impacted by the boil water advisory.

Barreto said additional testing that was done on Thursday could come back as early as Friday evening.

He said two negative tests would be needed for the company to lift the boil water advisory.