Hundreds of gallons of water rushed down Valley Vista Boulevard near Kester Avenue when the 8-inch pipe burst.
Several houses were briefly threatened with flooding but there are no reports of water inside any structures. The water flow was stopped after about an hour. No injuries were reported.
Department of Water and Power crews worked with Los Angeles firefighters to drain water and mud from some of the yards.
Streets in the area were shut down briefly because of flooding and broken pavement.
At least 40 customers were to be without water for a few hours while the pipe was repaired.
The Associated Press contributed to this report.