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Sewershed WI-053  ·  NYC DEP Combined Sewer Overflow Tributary Area

WI-053 - Riverdale, Bronx

Properties in this area share the WI-053 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 Riverdale, Bronx specifically.

WI-053 is a combined sewer area covering 171 properties in Riverdale, Bronx. Flood Form rates 35% of them Moderate or High for stormwater exposure, and 4% for groundwater. 86% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 166 ft. The median building dates to 1955. 20% of parcels sit over a historic stream or pond.

171

Properties in sewershed

86%

Legally eligible for on-site infiltration

35%

Stormwater exposure: Moderate or High

4%

Groundwater exposure: Moderate or High

What sets WI-053 apart

166 ft

Median ground elevation

38%

Average impervious cover per lot

1955

Median year built

20%

Properties over a historic stream or pond

Stats computed from Flood Form’s NYC parcel data as of October 9, 2026

Common solutions for Riverdale 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.

Want to see where your specific property stands?

Get Your Property’s Flood Form