Sewershed NR-056 · NYC DEP Combined Sewer Overflow Tributary Area
NR-056 - Sugar Hill, Manhattan
Properties in this area share the NR-056 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 Sugar Hill, Manhattan specifically.
NR-056 is a combined sewer area covering 588 properties in Sugar Hill, Manhattan. Flood Form rates 18% of them Moderate or High for stormwater exposure, and 32% for groundwater. 60% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 122 ft. The median building dates to 1910. 19% of parcels sit over a historic stream or pond.
588
Properties in sewershed
60.4%
Legally eligible for on-site infiltration
18%
Stormwater exposure: Moderate or High
32%
Groundwater exposure: Moderate or High
What sets NR-056 apart
122 ft
Median ground elevation
89%
Average impervious cover per lot
1910
Median year built
19%
Properties over a historic stream or pond
Stats computed from Flood Form’s NYC parcel data as of October 9, 2026
Common solutions for Sugar Hill 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
- NR-002Sugar Hill156 properties · 38% with Moderate or High stormwater exposure
- WI-046Harlem1,534 properties · 35% with Moderate or High stormwater exposure
- NR-003Washington Heights403 properties · 30% with Moderate or High stormwater exposure
- WI-045Harlem528 properties · 25% with Moderate or High stormwater exposure
- WI-051Washington Heights258 properties · 36% with Moderate or High stormwater exposure
- WI-064Concourse213 properties · 43% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form