Police officers said they first noticed a trickle of water coming from the bullet hole in the ceiling on the station's first floor, the Chicago Tribune reported Tuesday.
The trickle soon became a gushing stream that caused damage to computers and desks, police said. Fifteen prisoners awaiting court at the station were transferred to another location while officers waited two hours for city engineers to come repair the damage.
Police said the sergeant who accidentally fired off the gun will likely face internal disciplinary action.
There were no injuries reported from the shooting or the leaking water.