South County Residents Again Asked to Limit Water Use

South County residents who were affected last December by the rupture of a water main in Irvine are being asked to conserve water again next week, when a large stretch of the pipeline will be shut down for inspection.

The Municipal Water District of Orange County will shut off the Allen-McColloch pipeline from Feb. 7-14 to make sure there is no residual damage from the rupture. The areas served by the pipeline include Coto de Caza, Ladera Ranch, Laguna Woods, Laguna Hills, Lake Forest, Mission Viejo, Rancho Santa Margarita and the Talega development in San Clemente.

Although the three water districts that serve those cities will have their reservoirs completely full before the pipeline is shut down, water officials from the Metropolitan Water District of Southern California and the Municipal Water District of Orange County are asking residents in those areas not to water their lawns during the week, according to a written statement issued Feb. 2 by the agencies.

Unlike the urgent requests issued just after the breakage in December, the advance warning allows for a more laid-back approach toward residential customers.

“We’re not taking as extreme a position as we were last time because this is a planned event,” said John Schatz, general manager of the Santa Margarita Water District.

Water will be stored in advance for residential and business use, but irrigation in major greenbelt areas and construction grading operations will be curtailed. “We want to hit the homeowners last, not first,” Schatz said.

The massive pipeline burst Dec. 13, spilling about 5 million gallons of water that flooded over Portola Parkway and disrupted service to about 700,000 customers. Crews worked around the clock to replace 60 feet of damaged pipe, and the main line was back in operation within eight days. During that time, residents heeded the call to conserve water, cutting their usage to nearly half the average.

An investigation determined that human error and computer-system flaws were responsible for the surge of water pressure that burst the pipe, Metropolitan Water District officials concluded in January. An employee in the MWD’s Los Angeles operations center caused the rupture by opening, then shutting valves that sent water to the Santa Margarita Water District, according to MWD manager of water systems Jill T. Wicke. That caused a backward pressure surge that blew out a 10-foot section of the buried concrete-and-steel pipe.

During the inspection next week, MWD crews will begin draining the 69-inch pipeline at various locations beginning at 12:01 a.m. on Monday. Workers will inspect 9.5 miles of the 26-mile pipeline and use electronic testing equipment to determine if there was any other damage resulting from the rupture.