The rupture and subsequent mudslide was detected about 3:30 p.m. Sunday when a driver on Interstate 280 near Woodside reported seeing a large geyser of water to the Woodside Fire Department, the San Jose Mercury News reported.
Battalion Chief Kevin Butler said PG&E had been conducting hydrostatic testing of pipelines in the area.
There were no injuries and only one vehicle was damaged by dirt and rock, Butler said.
The Sunday incident came a little more than a year after the same pipeline burst, resulting in the deaths of eight people and damaging 38 homes in San Bruno, the San Francisco Chronicle noted.
Utility officials said they had workers in the area in case of future failure.
"We'll learn from this experience," spokesman Brian Swanson said. "It's definitely a concern that this hydrostatic pressure test impacted 280. We'll do an analysis to determine how we can minimize disruptions like this in the future."