Look at the two maps above. On the left is Manhattan in 1776. On the right is the Hurricane Sandy evacuation map. If your apartment's in Zone A in 2012, it would've been in the ocean in 1776, before the island was built up by landfill.
On the evac guide, red is Zone A, or the lowest lying area with the highest flood risk-in fact much of it is still under water. Greenwich Street, the eastern line of Zone A is on the edge of the Hudson River. ManhattanPast explains the correlation:
The eastern line of Zone A along the Hudson River runs along Greenwich Street, which was at the waterfront in 1776. The old slips on the East River extend inland to Queen Street, now Pearl Street, which is near where Zone A runs along the East River. Also notable on the 1776 map is Bayard's Mount, the high land rising in the area marked "Marshy Ground" north and northwest of the old Collect Pond. The pond was drained in the early 19th Century and Bayard's Mount was leveled to fill it in, but as can be seen in the evacuation plan, the pond and the marsh left their mark on modern Manhattan in the form of a hook-shaped low area delineated by the border of Zone B.
I guess once a flood zone, always a flood zone. [ManhattanPast]