This bill would require the Department of Environmental Protection (“DEP”) to determine areas at risk of groundwater flooding in New York City and add such areas to the flood hazard area map. The bill would also require DEP to consider the need to update the groundwater flood risk area when new data related to groundwater levels in New York City are available. The bill would also amend Appendix U of the Building Code to prohibit cellar or basement accessory dwelling units in groundwater flood risk areas 90 days after DEP updates such map.