Sewershed NCB-004 · NYC DEP Combined Sewer Overflow Tributary Area
NCB-004 - Greenpoint, Brooklyn
Properties in this area share the NCB-004 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 Greenpoint, Brooklyn specifically.
NCB-004 is a combined sewer area covering 910 properties in Greenpoint, Brooklyn. Flood Form rates 16% of them Moderate or High for stormwater exposure, and 15% for groundwater. 77% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 23 ft. The median building dates to 1901. 7% of parcels sit over a historic stream or pond.
910
Properties in sewershed
77.1%
Legally eligible for on-site infiltration
16%
Stormwater exposure: Moderate or High
15%
Groundwater exposure: Moderate or High
What sets NCB-004 apart
23 ft
Median ground elevation
81%
Average impervious cover per lot
1901
Median year built
7%
Properties over a historic stream or pond
Stats computed from Flood Form’s NYC parcel data as of October 9, 2026
Common solutions for Greenpoint 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
- NCB-027Greenpoint920 properties · 57% with Moderate or High stormwater exposure
- NCB-022Greenpoint318 properties · 39% with Moderate or High stormwater exposure
- NCB-007Williamsburg277 properties · 62% with Moderate or High stormwater exposure
- NCB-006East Williamsburg6,259 properties · 44% with Moderate or High stormwater exposure
- BB-013Long Island City119 properties · 64% with Moderate or High stormwater exposure
- BB-021Long Island City380 properties · 62% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form