PG&E owns the gas line up to and including the meter. Everything after the meter, the piping that runs through your walls, attic, crawlspace or yard to each appliance, belongs to the property owner. That is the piping we repair, replace and extend.
Most new gas line work comes from a change in the house: switching from an electric range to gas, adding a gas dryer, moving to a tankless water heater that needs more gas, or running a line to an outdoor kitchen, BBQ or fire pit. Repairs usually involve older black iron pipe that has corroded where it runs underground or through damp areas, failed flexible connectors, or leaking fittings.
Gas work is not the place to guess on sizing. A line that is too small starves the appliances at the end of it, so we size each run to the total load on the system, not just the new appliance.