The water flooded homes and temporarily shutdown northbound 101.
It happened around 9:30 pm near the intersection of 22nd Street and Rhode Island Street.
Water rushed down the sidewalks like a waterfall while crews from the San Francisco Water Department worked to stop the flow.
The water seeped under the garages and front doors of some of the homes on Rhode Island Street, creating a mess on Thanksgiving night.
Water also splashed out onto Highway 101 near the Cesar Chavez offramp.
CHP issued a sig-alert as all northbound 101 traffic was being diverted to 280.
The sig-alert was canceled just before 11pm, but water is still gushing from the broken main.
Firefighters say it could take four hours to fully shut off the water.