The water main break near the intersection of Estrella and Zion avenues was first reported around 11:15 a.m., said city water department spokesman Arian Collins.
Some traffic lanes near the intersection may be closed, said Collins and San Diego Police's Sgt. Ray Battrick.
Neither officials could confirm if there was flooding in the area.
Water was shut off to some homes near the intersection, but the number of homes affected was not immediately known, Collins said.
The water will be shut off until repairs are completed possibly around midnight, he said. Collins did not know what caused the water main to break.