The break occurred at 18th and Arch streets near the construction site of the new Comcast tower.
Action News viewer Kelsey Siano sent in video of the water gushing through the streets.
Chopper 6 over the scene on Action News at noon showed crews seemed to have the incident under control.
It is not known at this time the size of the water main.
SEPTA says the Regional Rail line may experience delays up to 20 minutes.
Thorndale: All Trains may be experiencing significant delays of up to 20 minutes due to a water main break at Surburban Station.— SEPTA (@SEPTA_PAO) June 2, 2016