The pipeline break in the 400 block of Henson Heights Drive in San Marcos was reported shortly before 2:30 p.m., sheriff's Lt. Kenn Nelson said.
1,000 gallons of water gushed down Liberty Dr. startling hundreds of residents.
The Vallecitos Water District said the 30 year old pipe was corroded. It typically has a life span of 50 years.
As Vallecitos Water District crews worked on the damaged pipeline, water was shut off. Around 9 p.m. crews had repaired the pipe, cleaned and cleared the area.