Holding the test tube to the light, Dawn White flicks the sample of well water, checking for cloudiness or gases that may have been emitted during the tube's two days in an incubator.
The water, which has been mixed in a broth that supports bacterial growth, is clear, indicating it is free of coliforms. If these harmless bacteria had been detected, their presence would have been a clue that pathogens, dangerous bacteria that could cause intestinal problems, might be lurking in the water.
Bulk of Workload
With 500 samples a month from California-American Water Co.'s 29 wells and distribution systems in the San Gabriel Valley, coliform-testing is the bulk of the workload for White, water quality supervisor at the firm's new laboratory in Rosemead. Cal-Am supplies about 20 million gallons of water daily to communities in Rosemead, El Monte, San Gabriel, Duarte, Bradbury, San Marino, Temple City and Baldwin Hills, White said.
Most chemical contaminants, such as oil or fertilizers, enter the underground water supply after being dumped by businesses and individuals. Bacterial contamination often results when underground water is exposed to airborne bacteria through corroded pipes or other problems. About 70 wells in the valley have been shut down because of contaminants found in water samples, according to Bob Berlien, general manager of the Upper San Gabriel Valley Municipal Water District.
The Main San Gabriel Basin, which supplies water to about 1 million residents, has been designated a Superfund cleanup site by the U.S. Environmental Protection Agency.
Cal-Am is the only one of the more than 40 private water suppliers in the valley with an in-house water-testing facility, Berlien said. The laboratory, which will also test supplies delivered to residents of Coronado, Newbury Park and parts of Camarillo, was dedicated Friday.
Most water companies contract with three major commercial laboratories in the area to meet testing requirements set by the state Department of Health Services, Berlien said.
"The cost of outside (commercial) testing is phenomenal," said David Stephenson, Cal-Am director of rates and revenues. If all the company's testing were contracted out to private labs, the price would be nearly $129,000, according to Jim McVeigh, Cal-Am director of water quality.
Even with the $250,000 lab in Rosemead, Cal-Am will still mail samples to its laboratory in Monterey, Calif., for more complicated tests for metals and organic and inorganic compounds, he said.
The firm's customers will pay less than $1 more per year to offset the costs of the lab, Stephenson said.
Coliform samples must be collected weekly because bacteriological conditions can change so quickly, White said. State law requires that one sample be tested for every 1,000 "services" the company supplies. A service could refer to a single home or an entire apartment complex.
If coliforms are found, the affected piping system would be flushed, and increased amounts of chlorine would be added to kill the bacteria, she said. Bacteria-free water from underground wells is routinely treated with low levels of chlorine to protect it from bacterial growth as it travel to the customers.
Aid for Maintenance
Test results also help with maintenance. "If the numbers (of bacteria) are high, it might indicate a growth in the pipes, which would lead to problems like corrosion," White said.
She also checks the levels of nitrates and fluorides. "A lot of the work we do is very routine because our wells are very clean," she said. Water from some Cal-Am wells in the San Marino-Pasadena area is blended with water purchased from the Metropolitan Water District to reduce high levels of nitrates.
"You do what you have to do to keep the system safe," she said.
Cal-Am decided to build the lab in Los Angeles because of the increasing number of compounds the state requires water companies to test for, McVeigh said.
The Department of Health Services will add at least 25 more compounds to the list this year, according to Susan Nielson, Pasadena's civil engineer in charge of water quality. Pasadena spends $30,000 a year for water-testing at commercial labs, although an in-house facility checks for particular contaminants.
The city, which supplies nearly 37,000 services from its own wells and water purchased from the Metropolitan Water District, is studying a lab expansion because of the expected increases in workload.
In-House Lab a Luxury
But most cities that supply their own water cannot afford the luxury of an in-house lab.
Arcadia, which pays $30,000 a year to send out all its samples for testing, still finds that cheaper than conducting its own tests, said Rita Kurth, administrative assistant for the city's water department. "We couldn't run a lab for $30,000 a year," she said.