People in nearly 5,300 households and businesses in Hacienda Heights are being advised to use bottled water for drinking and cooking because wells are contaminated by the industrial chemical dichloroethylene (DCE).
At the direction of the state Department of Health Services, the San Gabriel Valley Water Co. has mailed letters to its Hacienda Heights customers saying the state has recommended the use of bottled water until the problem can be solved.
The advisory affects 15,000 to 20,000 consumers, about one third of the unincorporated community's population.
Frank LoGuidice, chief engineer for the privately owned El Monte-based utility, said a new well is being drilled to find another source of water for customers. The well is expected to be operating within 30 days, he said.
Meanwhile, the Los Angeles County Board of Supervisors asked county health officials on Tuesday to conduct an assessment of possible health hazards and to determine the source of the pollution and what steps can be taken to correct it.
The supervisors also asked that bottled water companies be contacted to set up a distribution center in the Hacienda Heights area and that authorities inform residents about how the contaminated water can be safely used.
Gary Yamamoto, a senior sanitary engineer for the state Department of Health Services, said water from two of the San Gabriel Valley Water Co.'s five wells had average DCE concentrations of about 1 part per billion, far exceeding the state safety standard of .2 part per billion.
DCE, a chemical used as an industrial solvent and to make plastic, has been found to cause tumors in laboratory animals, Yamamoto said.
Since monitoring of the chemical began early this year, Yamamoto said, concentrations exceeding state standards have been found in at least 15 wells in Arcadia, Duarte, Claremont, East Los Angeles, Los Angeles, Norwalk, Pasadena, Pomona and Santa Monica. In those cases, however, the water could be treated or the wells could be closed without any direct effect on consumers, he said.
LoGuidice said his firm, which serves 42,000 customers in the San Gabriel Valley, received about 70 calls on Tuesday.
"Naturally, we do not like to alarm customers, and we do not know what the health risks are," LoGuidice said. "I understand it's a long-term thing. We're not questioning the health department's reasoning. We'll do whatever we are obligated to do."
Vera Melnyk, an associate engineer for the state Department of Health Services, said the water company closed two wells last spring after high DCE levels were found. Supplies were adequate to provide water from the three remaining wells until Aug. 26, when the company was forced to return the two wells to operation, she said.
Melnyk said the cause of the contamination is not known. He added that it could have come from several sources, including abandoned dump sites, illegal disposal of the chemical or leakage from underground storage tanks.
"This sort of thing has never happened to me," Jennifer Blevans, who has lived in Hacienda Heights for seven years, said of the three-paragraph letter she received from the water company. "I really don't think this is enough of an explanation. I think it's kind of unconscionable for them to sell us water that's supposed to be undrinkable and then charge us for it."