A nearly century-old 48-inch water main burst before dawn Tuesday at Juniper and Sansom Streets, flooding the surrounding blocks in Center City and knocking out power to hundreds of Peco customers.
The break spewed from 14 million to 15 million gallons of water into the streets before leaving behind a muddy mess and a sinkhole at the site of the break, Water Commissioner Debra McCarty said. Cleanup and repairs could take days, and the cause of the break is under investigation.
Asked whether road construction might have affected the water main, McCarty said, "That's certainly something we're going to take into consideration in our evaluation.
"We do know that disturbance of large mains, whether today or 50 years ago, can have an impact on the resiliency of that pipe," McCarty said. "But that's all part of our investigation, and we won't know for probably a couple of weeks what caused this break."
The flooding was reported around 4 a.m. and it took Water Department crews about three hours to stop the flow.
Walnut Street reopened Tuesday afternoon. Sansom remained closed between 13th and Broad Streets, as did Juniper between Chestnut Street and Walnut.
About 750 customers near the break lost power, though most were expected to have electricity restored by Tuesday night, according to Peco.
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Businesses were assessing damage from the water, which triggered alarms as it rushed into some buildings in the pre-dawn hours.
Howard Taylor, the manager at the IHOP restaurant at Walnut and Juniper, arrived to find ankle-deep water throughout the dining room. He said he hoped that the restaurant could reopen Wednesday, but was awaiting a damage assessment.
Other places in the area, which has a large number of restaurants, also reported damage. The owner of one Sansom Street bar reported seeing beer kegs floating in about 5½ feet of water in the basement.
"There was so much water pouring in, it was insane," said Jason Evenchik, owner of Time, on Sansom Street, and three other bars in the Washington Square area.
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Any property owner who suffered damage can file a claim with the city by calling the Office of Risk Management at 215-683-1730 or obtaining a claim form online. State law limits the city's financial liability to $500,000 per event.
Among those that also lost water was Thomas Jefferson University Hospital, where officials had water brought in until service was restored around 10 a.m.
John DiGiulio, a Water Department spokesman, said cleanup and repairs could take days.
"I would never want to say to someone that we'll be cleaned up today," he said. "We will have a presence here for a while."
The main dates from the 1920s, officials said. A recent inspection using technology that goes inside the pipe turned up no problems.
While the cause of the break remains unknown, DiGiulio said increased water usage in the summer months tends to stress pipes. The region is in the fifth day of a heat wave.
"In the summer months, we do see a higher volume of water usage that could be putting additional stress on our transmission mains; that's usually what causes these is higher volume usage," he said. "Hot days, summer days, extra showers, more air-conditioning running, certainly could be something that might have played a factor here, but way too early to tell."
Laura Copeland, another Water Department spokesperson, said the city is replacing 28 miles of mains per year, and is set to increase that to 42 miles per year within the next six years under its long-term capital plans. The city has $188 million budgeted for the next three years for water-main replacements.
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Earlier in the day, more roads were shut down in the affected area, which stretched from Locust Street to Chestnut and 12th Street to Broad. The closures prompted SEPTA to put several bus routes on detours.