Sewershed NCM-063 · NYC DEP Combined Sewer Overflow Tributary Area
NCM-063 - Two Bridges, Manhattan
Properties in this area share the NCM-063 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 Two Bridges, Manhattan specifically.
NCM-063 is a combined sewer area covering 446 properties in Two Bridges, Manhattan. Flood Form rates 45% of them Moderate or High for stormwater exposure, and 7% for groundwater. 21% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 36 ft. The median building dates to 1910. 12% of parcels sit over a historic stream or pond. According to NYC DEP green infrastructure records, this sewershed drains to East River / Open Waters. NYC DEP has built 8 green infrastructure assets here.
446
Properties in sewershed
21.3%
Legally eligible for on-site infiltration
45%
Stormwater exposure: Moderate or High
7%
Groundwater exposure: Moderate or High
What sets NCM-063 apart
36 ft
Median ground elevation
97%
Average impervious cover per lot
1910
Median year built
12%
Properties over a historic stream or pond
Stats computed from Flood Form’s NYC parcel data as of October 9, 2026
Common solutions for Two Bridges 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-042Lower East Side154 properties · 47% with Moderate or High stormwater exposure
- NCM-050Chinatown1,193 properties · 46% with Moderate or High stormwater exposure
- NCM-028Lower East Side263 properties · 51% with Moderate or High stormwater exposure
- NCM-057Lower East Side158 properties · 50% with Moderate or High stormwater exposure
- NCM-020East Village623 properties · 54% with Moderate or High stormwater exposure
- NCM-078Financial District112 properties · 74% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form