Oakland water main break floods homes, roadway

A water main break Friday morning caused significant roadway flooding, closing part of a highway on-ramp in Oakland’s Dimond district and sinking a large swath of a residential street, officials said.

A 16-inch water main broke in the area of Montana Street and Dimond Avenue, causing water to stream onto part of an Interstate 580 on-ramp, said Nelsy Rodriguez, a spokeswoman for the East Bay Municipal Utility District.

The water line, made of cast iron, was installed in 1932, Rodriguez said. What caused it to break was difficult to immediately pinpoint, she said.

“It’s really difficult to say with main breaks,” she said. “We don’t know how long it had been leaking, but it gave way today.”

Utility workers shut off water to stop the flood. Twelve homes and apartments were affected, and several had significant flooding inside, Rodriguez said.

The main part of the on-ramp wasn’t impacted, said Officer Sean Wilkenfeld, a California Highway Patrol spokesman. The on-ramp that CHP officers closed feeds into the main roadway that goes onto the highway, he said.

On Montana Street, a giant sinkhole formed and buckled the street and part of the sidewalk, Rodriguez said, with the damage measuring roughly 10 by 5 feet across and 3 feet deep. Some of the concrete pieces were swept under cars in the area, and residents had to move their cars to neighboring streets.

Traffic on surrounding city streets may be heavier than usual, Wilkenfeld said.