About 375,000 residents of south and east San Diego County may be temporarily cut off from their sole source of treated water later this month when the San Diego County Water Authority repairs its troublesome Pipeline 4, officials said Wednesday.
The anticipated weeklong interruption in water deliveries will probably put individual consumers in a pinch, but not leave them high and dry.
James Melton, a spokesman for the water authority, said it is possible that the three municipal water districts that rely on Pipeline 4--Helix, Otay and Padre Dam--will be able to store enough water to meet their customers' needs during the repairs, which are likely to begin in late May or early June.
Officials at both the Helix and Otay districts say they will ask customers to cut back to emergency levels during the repairs--forgoing outdoor watering and skimping as much as possible indoors.
"We will ask people to use only what's necessary," said Keith Lewinger, general manager of the Otay Water District. "No outdoor watering. Construction sites closed down. We expect a 50% to 60% drop in our demand, and that's what we need to be able to make it through this."
Robert D. Friedgen, Helix's general manager, agreed.
"It will be an emergency as far as our water supply is concerned," he said. "The only way we're all going to get through this is to work together."
Pipeline 4 is the same one that ruptured in September, leaving nearly 200,000 residents of the Otay and Padre Dam districts with just three days' supply of stored water.
More recently, Melton said, the 17-year-old concrete pipe--one of the authority's newest--has been corroding, particularly in sections where it crosses Miramar Naval Air Station east of Interstate 15. Water authority engineers fear that, if not repaired, the corrosion could cause the pipe to fail.
"We are experiencing more difficulties than typically would be expected on a pipeline of that size and age," Melton said, adding that pipes usually last 50 to 100 years. "There's no one person or thing to blame for it. The range of possibilities includes the manufacturer of the pipe, how it was transported, how it was placed in the ground, the soils surrounding it."
Whatever the cause, Melton said, the problems will probably mean more interruptions in deliveries.
"This will be done again in the future," he said of the cutoff.
In the authority's 222-mile system of pipe, about 80 miles are made of pre-stressed concrete, as is Pipeline 4. Officials said all 80 miles will be inspected for damage later this year.