Massive San Francisco sinkhole forms after water main break

A ruptured water main created a massive sinkhole in San Francisco's Cow Hollow neighborhood.

The scene at Fillmore and Green streets was chaotic Monday afternoon as crews worked to repair the sinkhole. The incident occurred after a 16-inch water main broke around midnight.

For hours, water flowed underground, causing the pavement to buckle at the intersection's center. The excess water flowed down Fillmore Street, subsequently flooding Filbert and Union streets.

Neighbors recorded video of water and mud filling up streets in the area.

"It was the sound of the car alarms that initially woke me up, and then when I came outside to see what was going on, the water," said resident Nicole DeMarinis. "It was just rushing water coming through, it was insane, this whole thing was filled with water."

Another challenge faced by the crews was the removal of fallen pavement that had settled onto a four-inch gas line.

Firefighters said that Pacific Gas and Electric crews were called in to assist in the safe removal of the slab covering the gas line. The gas line had become bent during the water main rupture.

PG&E crews monitored for gas leaks throughout the day with firefighters on standby.

"At this time there is no rupture of actual gas," said fire Captain Jonathan Baxter. "There is no gas leak. Therefore, there is no hazard to the general public."

The San Francisco Public Utilities Commission said the aging water main failed catastrophically. 

"What we know so far is that the leak is from a 16-inch water main that is probably well over 70 years old," explained said Joseph Sweiss, spokesperson for the utilities commission. "So, again, this is a large pipe, it's old."

Business owner Kingston Wu said he began receiving texts overnight from staff at his restaurant Wilder SF. He arrived at his restaurant that morning to survey the damage.

"Before coming in today, I thought that maybe this was a one-day turnaround," he said. "After coming in, walking the floor, looking at the neighbors, I feel that it's optimistic for us to think that we can reopen on Friday."

Wu said contractors will be working to remove the mud covering about three-fourths of his floor and start working to repair the damage.

"Our immediate plan is just to tear out all the floor in the restaurant and dry it out and then kind of plan our rebuilding from there," Wu said.

This is no estimated time of when repair work to the sinkhole will be finished.