Construction crews broke through the 2-inch pipeline Sunday evening KTVU, San Francisco, reported.
No injuries were reported and no evacuations were ordered, the broadcaster said.
In 2010, an explosion in a PG&E natural gas pipeline killed eight people and damaged more than three dozen homes in San Bruno.
The National Transportation Safety Board, in its investigation into the 2010 disaster, said PG&E didn't know what kind of pipe was beneath San Bruno. A defective weld seam on the pipeline was blamed for that explosion.