Bacteria found in Downey's water supply

City, state and county public health officials issued a boil-water order about 6 p.m. Thursday, said Gerry Greene, a principal civil engineer with the Downey Public Works Department.

Residents may continue to shower or bathe in water from the tap, but they are being strongly cautioned to boil it before drinking, including water for pets.

City officials could not be reached this morning, but a statement on the city website says Downey tests its water weekly. Testing on Tuesday showed a positive reading for the coliform bacteria at three of the city's 25 sampling locations.

Coliform bacteria are naturally present in the environment and are used as an indicator of other, potentially harmful bacteria. But E. coli and fecal coliform bacteria, which have the potential to pose a serious health problem, have not been detected in the city's water.

The source of the bacteria has not been determined, the statement said.

The boil-water order will continue for at least three days while water supplies are hyperchlorinated and the lines where the bacteria were found are flushed. City crews are flushing water from fire hydrants in the affected areas, and chlorine is being added to disinfect the pipelines.

The city's Public Works Department released a list of responses to frequently asked questions on the boil-water order on its website.

Southern California derives its water from a variety of sources that may become contaminated. In December, San Diego County health officials ordered a nudist camp to boil its water after tests found coliform bacteria. The Sun Island Resort near El Cajon, one of the oldest nudist camps in Southern California, gets its water from wells, which are tested monthly.

francisco.varaorta@latimes.com