Neighbors said the water flowed from the hydrant near 108th Street and Perry Avenue.
The Chicago Water Department received a call about the fire hydrant at about 2:30 a.m. and the water was turned off by about 6:30 a.m. The Water Department will do an emergency repair of the hydrant on Monday.
A neighbor said someone was attempting to fill a brand-new pool by jamming a garden hose down the hydrant.
All that's left now are some small puddles, but people in the area say it's a different story in their basements.
Some cars were also damaged. The pool in question did not get filled up.