About five residents and businesses in the area were affected by the leak, PG&E spokeswoman Jana Morris said.
The leak was reported at approximately 4:45 p.m. near Main Street in Half Moon Bay and a Sig-alert was issued by the California Highway Patrol.
Highway 92 was shut down in both directions between Half Moon Bay and Skyline Boulevard, but was reopened at about 5:25 p.m., according to the CHP.
However, power wasn't restored until 8 p.m., Morris said.
CHP Officer Peter Van Eckhardt said that the roadway reopened after PG&E crews were able to close the main.
According to Morris, the leak was the result of a failed regulator.
"A regulator is part of a larger system that allows gas pressure to reach an appropriate level for it to be distributed to customers," she said.