The chemical makeup of well water, not copper tubing, has caused pinhole leaks that have plagued more than 1,000 homeowners during the past seven years, according to a report by a corrosion engineer.
The problem, which has cost some homeowners as much as $15,000, can be solved by treating the water with caustic soda, said Donald Reedy, owner of D. R. Reedy/P. E., an engineering firm in Alta Loma.
Reedy was hired by the city to conduct the $9,800 study after it became apparent that residents no longer trusted either the city or California-American Water Co., which supplies water to Duarte. The city released Reedy's report Wednesday at a meeting with residents and the water company.
Homeowners have spent at least $300,000 repairing pipes as the leaks recurred over the years. Cal-Am has admitted no liability for problems with well water.
Although only a small amount of water may leak, the steady drip can cause serious property damage, homeowners say.
Some have replumbed their entire homes at a cost of up to $15,000, said Christina Sidrow, who conducted an informal survey of other homeowners to determine the extent of the problem.
The problem of water leaking through tiny holes in copper water pipes began in the early 1980s, when eight developers built 2,000 homes using copper pipes in Community Redevelopment Agency project areas in northeast Duarte.
By 1982, homeowners, realizing that their leaks were not isolated incidents, organized and began complaining to the city.
City Manager Jesse Duff said that when the problem first surfaced, the city "took the position of being a mediator, facilitating meetings and communications between homeowners, developers and the water company."
Until last year, some of the developers and homeowners' insurance companies paid for repairs to the pipes and damage caused by the leaks.
Then they stopped payments because they thought the problems would continue until the composition of the water was changed, said Peg Kean of Kaufman & Broad Home Corp.
Kaufman & Broad built 231 homes in Duarte between 1979 and 1982. Of those, 131 developed leaks, and the company made 275 repairs at a cost of $100,000, Kean said.
When the homeowners began complaining in 1982, Cal-Am commissioned a study by Henry Cruse, a corrosion engineer. He reported that although the specific factors causing the rapid pitting of copper were difficult to determine, the remedy must involve treating the water, since the pipe cannot be readily replaced.
Cruse reviewed several possible solutions and concluded that injecting caustic soda would be the most economical method of adjusting the chemical content of Duarte's water.
The issue lay dormant until last March, when homeowners with pinhole-leak problems appealed to the City Council, which approved the independent study conducted by Reedy.
After nearly 200 irate homeowners demanded a solution to the problem at a town meeting in August, three steps were taken.
The city hired Reedy, who was chosen by the homeowners, to study the situation. It also filed a complaint with the state Public Utilities Commission, which has regulatory power over the water company and can ask it to provide better-quality water. At the request of the city and Cal-Am, the PUC delayed scheduling a hearing on the complaint until the water company completes a $30,000 pilot program.
That program, which could be completed by May, involves injecting caustic soda into the well water delivered to 230 homes in one tract. Engineers say caustic soda may correct the corrosiveness of the water, which has a low pH (alkalinity) level and a high level of carbon dioxide.
"We did a telephone survey this month of those homeowners, and there have been no indication of leaks since the program began" in November, said Andrew Krueger, district manager for Cal-Am. "But the study so far is too preliminary to see any results," he said.
Krueger, who said Cal-Am would not comment on the Reedy report, does not regard the use of caustic soda as a feasible long-range solution for the 6,000 residences in the city.
He said that the initial cost of such treatment could run as high as $800,000 and that changing the pH level could cause a buildup of calcium carbonates inside pipes and hot-water heaters, restricting the flow of water.
Reedy said the caustic soda would be injected either into the wells or into the water after it has been pumped from the wells.
Krueger said Cal-Am would rather stop using well water. The firm has proposed building a $2.5-million filtration plant that would allow it to pump water directly from the San Gabriel River.
Cal-Am also wants its customers to pay for the plant. In 1985, it applied to the PUC for a rate increase to finance the project. The PUC denied the increase, but Cal-Am plans to resubmit its request. If it prevails, it will build the plant in about two years.
However, residents do not want to wait that long. Their frustration was expressed at Wednesday's meeting between city and Cal-Am officials and a small, informal group of homeowners who represent the rest of the residents.
When Chuck Shaw, Cal-Am's operations manager, said the pilot study could take a year, residents asked whether Cal-Am would abide by Reedy's solution if that was the one endorsed by the city.
"We don't necessarily agree with the report," Shaw said. "We didn't choose Reedy."
Reedy said that although he recommends the injection of caustic soda, a decision should be postponed until the pilot program is completed. He expressed confidence that the program will prove that caustic soda will solve the problem. But some residents, saying they do not trust Cal-Am to accurately report the results of the pilot program, asked that Reedy monitor the program.
The council is expected to agree next month to pay Reedy an additional $2,000 to perform the monitoring.