Rooftop detention systems, or Blue Roofs, temporarily store and gradually drain rainwater off a building's rooftop in order to slow the flow of stormwater into the City's sewer system when it rains.

Installing a rooftop detention system is a low-cost option that can help you meet the City's stormwater detention requirement.

Call 311 or 212-NEW-YORK (212-639-9675) for help.