Sewershed NCM-049 · NYC DEP Combined Sewer Overflow Tributary Area
NCM-049 - Gramercy, Manhattan
Properties in this area share the NCM-049 combined sewer — during moderate-to-heavy rain, runoff can exceed pipe capacity faster than it drains, which is what drives sewer backup exposure block by block. Here’s what that looks like for Gramercy, Manhattan specifically.
NCM-049 is a combined sewer area covering 760 properties in Gramercy, Manhattan. Flood Form rates 53% of them Moderate or High for stormwater exposure, and 12% for groundwater. 56% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 29 ft. The median building dates to 1910. 28% of parcels sit over a historic stream or pond.
760
Properties in sewershed
56.1%
Legally eligible for on-site infiltration
53%
Stormwater exposure: Moderate or High
12%
Groundwater exposure: Moderate or High
What sets NCM-049 apart
29 ft
Median ground elevation
95%
Average impervious cover per lot
1910
Median year built
28%
Properties over a historic stream or pond
Stats computed from Flood Form’s NYC parcel data as of October 9, 2026
Common solutions for Gramercy properties
Downspout Diversion
Redirects roof runoff away from the combined sewer and into landscaped or permeable areas on the lot.
Infiltration System
Drywells or infiltration chambers that let stormwater soak into the ground on-site instead of entering the sewer.
Detention System
Holds stormwater temporarily and releases it slowly, reducing peak flow into the combined sewer during a storm.
Drain Improvement
Upgrades yard, area, or foundation drains so water is carried away from the building instead of pooling.
Foundation Waterproofing
Protects the foundation from groundwater intrusion, relevant where groundwater exposure runs high.
Nearby sewersheds
- NCM-046Gramercy149 properties · 70% with Moderate or High stormwater exposure
- NCM-087Flatiron123 properties · 20% with Moderate or High stormwater exposure
- NCM-052East Village1,790 properties · 58% with Moderate or High stormwater exposure
- NCM-045Midtown South483 properties · 50% with Moderate or High stormwater exposure
- NR-023Flatiron883 properties · 62% with Moderate or High stormwater exposure
- NCM-041Murray Hill765 properties · 46% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form