Sewershed NCM-073 · NYC DEP Combined Sewer Overflow Tributary Area
NCM-073 - Tribeca, Manhattan
Properties in this area share the NCM-073 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 Tribeca, Manhattan specifically.
NCM-073 is a combined sewer area covering 441 properties in Tribeca, Manhattan. Flood Form rates 54% of them Moderate or High for stormwater exposure, and 25% for groundwater. 15% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 19 ft. The median building dates to 1900. 16% 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 1 green infrastructure asset here.
441
Properties in sewershed
14.7%
Legally eligible for on-site infiltration
54%
Stormwater exposure: Moderate or High
25%
Groundwater exposure: Moderate or High
What sets NCM-073 apart
19 ft
Median ground elevation
98%
Average impervious cover per lot
1900
Median year built
16%
Properties over a historic stream or pond
Stats computed from Flood Form’s NYC parcel data as of October 9, 2026
Common solutions for Tribeca 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-074Tribeca132 properties · 27% with Moderate or High stormwater exposure
- NCM-075SoHo1,185 properties · 63% with Moderate or High stormwater exposure
- NCM-050Chinatown1,193 properties · 46% with Moderate or High stormwater exposure
- NCM-078Financial District112 properties · 74% with Moderate or High stormwater exposure
- NCM-067Financial District180 properties · 63% with Moderate or High stormwater exposure
- NCM-069Financial District156 properties · 72% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form