The break gushed water into the streets on Newell Road between Channing Avenue and Embarcadero Road at about 2 a.m., officials said.
The line was shut off and service is not expected to be restored until late this afternoon.
Utility officials said the cause of break appears to be connected to cold overnight temperatures.
According to the National Weather Service, the temperature dipped to 35 degrees around 2 a.m. this morning.
