The pipe that broke dates back to 1895 and is in the process of getting repaired.
The water main burst in the middle of the street, spewing a non-stop flow of water for more than an hour, flooding the busy area near the Moscone Center.
Water rushed into the parking garage at Moscone south, flooding the loading dock and the central subway project was also impacted. "It's under water, about a foot under water, so we got some pumping to do," central subway project spokesperson Rod Bowyer said.
Bowyer says the underground tunnel quickly filled up. "We got three levels and each level's flooded, but the bottom is a foot under water or more," he said.
This was a 12-inch water main that burst because the pipe very old. "So the pipeline that broke dates back to 1895 and so usually when you have a pipe that is that old, age is a likely factor," San Francisco Public Utilities Commission spokesperson Charles Sheehan said.
Traffic control is diverting cars around the area and repairs are expected to go well into the afternoon. "Once we open up the street, we'll be able to assess how much erosion, how much damage there is beneath the road," Sheehan said.