The FDNY says the water leak happened in a condo building at 337 Lenox Road in the Prospect Lefferts Gardens section.
It is believed to be a broken sprinkler pipe due to temperature changes.
The leak forced a full evacuation of the building, which also houses the High Definition Kids Preschool Day Care Center on the first floor.
The Fire Department has a de-watering unit at the scene to pump out the basement.
No injuries were reported.
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