Cause of Orange County Water Pipe Break Sought

Orange County officials Tuesday probed a variety of possible causes, including a recent earthquake and defective construction, for a massive water main rupture that forced much of south Orange County into drought-like conservation measures.

More than 700,000 customers in 14 communities were affected by the shutdown Monday night of one of two main water supply lines. Water officials said the main could be repaired by early next week.

Meanwhile, many residents were taking the request to conserve water in stride.

“Usually, we use water when we need it, but we’ll take even quicker showers,” said Liz Forrest, 40, of Rancho Santa Margarita, who recalled the drought-inspired conservation efforts of a decade ago. “We were asked [then] not to flush toilets as much. We can do that again. We’ll wash dishes by hand rather than use the dishwasher.”

For several residential construction projects, though, the effect was more serious: Officials for the Santa Margarita Water District cut water supplies used for compacting, controlling dust and spreading dirt.

“We’ve shut them off,” said Santa Margarita general manager John Schatz. “We’ve told them they can’t have any more water.”

Water authorities remained uncertain about the cause of the failure, saying that possible factors include corrosion of the 18-year-old pipe or a seismic subterranean shift linked to last week’s magnitude 3.9 earthquake seven miles from Yorba Linda.

Similar pipelines from a variety of manufacturers have failed in the past, with more than 40 breaks occurring worldwide since 1950, according to a 1992 federal lawsuit filed in Arizona. In previous instances, some of the steel within the pipes had corroded or broken.

“We won’t rule [earthquake damage] out, but chances are we’re looking at some sort of failure here,” said Keith G. Coolidge, associate general manager of the Municipal Water District of Orange County. “This is something you wouldn’t expect in a pipeline this young.”

But Tom Giese, president of the Rancho Cucamonga company that manufactured the pipe, the Ameron Concrete and Steel Pipe Group, described the 69-inch steel-and-concrete pipe as “middle-aged.”

“It’s up there,” he said. “It’s quite a lengthy service period.”

Despite the rupture of such a key line, no service problems, such as reduced pressure, were reported. But that could change drastically if the Metropolitan Water District cannot replace the broken pipe before reservoirs run dry, which could happen in seven to 10 days. Officials planned to check reservoir levels today to determine how much supply is on hand.

If repairs are delayed, more drastic emergency steps could be taken.

“We really need people to conserve. I don’t want to be an alarmist, but conservation is what’s going to make the difference here,” Coolidge said. “As long as we do that, I don’t think anybody will be without.”

Workers struggled Tuesday to excavate the site of the break, about 25 feet underground near the Portola Parkway northeast of the former El Toro Marine Corps Air Station.

The rupture occurred where two sections of 20-foot-long, S-shaped pipes came together in a slight bend following the contours of a shallow canyon. With pressure nearing 300 pounds per square inch, the force of the water propelled chunks of the concrete-encased steel pipe to the earth’s surface.

About 5 million gallons of water gushed from the rupture before it was shut off.

The Metropolitan Water District of Orange County built the main pipeline in 1981, and in 1995 turned the system over to the Metropolitan Water District of Southern California. It was last inspected, at the time of the sale, Coolidge said. The next inspection had been scheduled for early next year.