The pipeline in question runs underneath Brittan Ave. It's four miles long and according to city leaders, a potential danger to the neighborhood.
PG&E insists nothing is wrong with Line 147. The utility is only turning off the natural gas transmission line because a judge told them to.
San Carlos residents who live along the pipeline are relieved.
"Good, perfect," San Carlos resident Dolores Riviello said. "Yeah, I don't want to be in danger."
City leaders asked a judge to step in after PG&E emails surfaced questioning the safety of an 83-year-old seam weld on Line 147.
The transmission line, which runs between Highways 280 and 101, is similar to the pipeline that exploded in San Bruno three years ago. Eight people died from that blast and 38 homes were destroyed.
"Who knows what's down there," San Carlos Mayor Bob Grassilli said. "Their records are faulty."
The mayor says the hope is for PG&E to do a thorough inspection while the pipeline is turned off.
The utility says a water strength test conducted two years ago showed it to be safe, but city leaders want more proof.
"We haven't gotten answers to those questions," Mayor Grassilli said. "When we get answers to those questions with the engineers and the professionals doing this, then hopefully we'll be in good shape. But we don't know what the outcome's going to be."
It's unclear how long the pipeline will be shut down.
PG&E says customers shouldn't notice any disruption in service.
Either way, San Carlos residents are happy with what's going on.
"I would probably err on the side of doing the safe thing, especially after what happened," San Carlos resident Evan Esterman said. "I mean, how many people died in San Bruno?"
PG&E says the process of shutting down a transmission line takes hours, which means Line 147 won't be completely shut down until the end of business Monday.