Sewershed NR-004 · NYC DEP Combined Sewer Overflow Tributary Area
NR-004 - Washington Heights, Manhattan
Properties in this area share the NR-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 Washington Heights, Manhattan specifically.
NR-004 is a combined sewer area covering 297 properties in Washington Heights, Manhattan. Flood Form rates 49% of them Moderate or High for stormwater exposure, and 14% for groundwater. 71% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 192 ft. The median building dates to 1923. 28% of parcels sit over a historic stream or pond.
297
Properties in sewershed
71.4%
Legally eligible for on-site infiltration
49%
Stormwater exposure: Moderate or High
14%
Groundwater exposure: Moderate or High
What sets NR-004 apart
192 ft
Median ground elevation
95%
Average impervious cover per lot
1923
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 Washington Heights 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
- WI-052Washington Heights365 properties · 33% with Moderate or High stormwater exposure
- WI-051Washington Heights258 properties · 36% with Moderate or High stormwater exposure
- NR-006Washington Heights657 properties · 53% with Moderate or High stormwater exposure
- NR-003Washington Heights403 properties · 30% with Moderate or High stormwater exposure
- WI-061Highbridge296 properties · 48% with Moderate or High stormwater exposure
- WI-059Morris Heights378 properties · 37% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form