Sewershed WI-035 · NYC DEP Combined Sewer Overflow Tributary Area
WI-035 - East Harlem, Manhattan
Properties in this area share the WI-035 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 East Harlem, Manhattan specifically.
WI-035 is a combined sewer area covering 220 properties in East Harlem, Manhattan. Flood Form rates 47% of them Moderate or High for stormwater exposure, and 11% for groundwater. 24% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 17 ft. The median building dates to 1919. 3% of parcels sit over a historic stream or pond.
220
Properties in sewershed
23.6%
Legally eligible for on-site infiltration
47%
Stormwater exposure: Moderate or High
11%
Groundwater exposure: Moderate or High
What sets WI-035 apart
17 ft
Median ground elevation
82%
Average impervious cover per lot
1919
Median year built
3%
Properties over a historic stream or pond
Stats computed from Flood Form’s NYC parcel data as of October 9, 2026
Common solutions for East Harlem 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-031East Harlem155 properties · 33% with Moderate or High stormwater exposure
- WI-037East Harlem260 properties · 32% with Moderate or High stormwater exposure
- WI-025East Harlem622 properties · 31% with Moderate or High stormwater exposure
- WI-038Harlem671 properties · 30% with Moderate or High stormwater exposure
- WI-024Harlem1,767 properties · 33% with Moderate or High stormwater exposure
- WI-067Mott Haven265 properties · 23% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form