The gas was squeezed off at 5:40 p.m., and three customers are without gas, PG&E spokeswoman Brittany McKannay said. There is no estimate when their service will be restored.
A backhoe struck the 4-inch gas line around 2:20 p.m. on Bolling Drive, Novato Fire Protection District Battalion Chief Bill Tyler said.
Residents of homes in the eighth- to quarter-mile area around the leak were advised to shelter in place, Tyler said.
Streets that were blocked off included Chrissy Place, Mather Court, Moffett Court, Tinker Way, Randolph Drive, Kelly Court, and parts of Bolling Drive, Tyler said.
About 12 preschool children in the playground at Hamilton School were told to remain at the school until their parents could pick them up, Tyler said.
A tow truck driver complained of light-headedness and was taken by the Novato Fire Protection District to a hospital, Tyler said.