The main was shut off about 1:30 p.m., Water Department spokesman John DiGiulio said, and full water pressure was restored to all customers around the same time.
Workers had been searching for a known leak in the area for about a week, McCarty said. They had pinpointed a failing joint on the 36-inch main, but it ruptured just as they were uncovering it to begin making repairs, DiGiulio said by phone Saturday. He said the workers did not strike the pipe or cause the break.
No customers lost water entirely, McCarty said, but low water pressure can be difficult to distinguish from a full loss of service.
Residents in Old City and Northern Liberties reported problems with their water, as did people as far west as 21st and Spruce and as far south as Third and Federal.
Mayor Nutter said three families were evacuated briefly.
The Positano Coast restaurant, on the second floor of a building at Second and Walnut Streets, was also evacuated about 1 p.m. The restaurant had some guests for lunch, operating partner Enrico Castro said, as well as a bridal shower.
The Fire Department evacuated the building, and Castro said he did not know where the bridal shower went because of how quickly everything happened.
The restaurant reopened for business at 5 p.m., but streets remained closed and Castro said most of the nearly 300 dinner reservations were canceled.
"Unfortunately, it's something that happened on a Saturday, so we basically lost half of the business tonight because the street's completely blocked," he said. "We lost lunch, but definitely it affected dinner."
Walnut Street remained closed Saturday night from Second to Fourth Streets, and Third Street was closed from Locust to Chestnut Streets. DiGiulio could not say when the streets would be reopened.
The force of the water knocked over a mailbox and forced open a metal street grate. In some areas, standing water was reported. At Dock and Front Streets, Monika Maslany of Fishtown said she saw water halfway up parked cars.
Nutter credited the Water Department for shutting off the main as quickly as possible - 75 minutes - and said the city would investigate the break in relation to other recent breaks.
"There's really no consistency from one water-main break to the next," said Nutter, who visited the site. "Some of it certainly is aging infrastructure, but sometimes they get a hairline crack because of the amount of water and pressure, which could blow a part of it out."
There have been several high-profile water-main breaks this year. McCarty and DiGiulio said that small breaks occur daily and that this year happened to have some larger ones.
Philadelphia has averaged 750 breaks per year during the last 28 years, DiGiulio said. For the fiscal year that ended June 30, he said, the city had 531 breaks, its third-lowest annual total.
Maslany and Heather Campbell of Center City had gone to Old City on Saturday to visit the Polish American Cultural Center at Third and Walnut.
When they got off I-95, they were forced to drive around the flowing water. They were soon passed by fire trucks with blaring sirens.
"It made it a little more exciting," Maslany said. "It gave us an adventure first with the water and then dodging fire trucks and finding parking."
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