The rupture was reported at about 6:30 a.m. in a residential area near the intersection of Helen Drive and Magnolia Avenue, Detective Rebecca Rosenblatt said.
No evacuations were necessary, she said.
Crews stopped the flow of water just after 9 a.m. and were continuing to work to repair the pipe.
Full service was expected to be restored in about three to five hours.
The rupture was affecting water pressure throughout the city, Rosenblatt said.