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Sewershed OH-002  ·  NYC DEP Combined Sewer Overflow Tributary Area

OH-002 - Borough Park, Brooklyn

Properties in this area share the OH-002 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 Borough Park, Brooklyn specifically.

OH-002 is a combined sewer area covering 17,937 properties in Borough Park, Brooklyn. Flood Form rates 34% of them Moderate or High for stormwater exposure, and 4% for groundwater. 70% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 72 ft. The median building dates to 1925. 1% of parcels sit over a historic stream or pond. According to NYC DEP green infrastructure records, this sewershed drains to East River / Open Waters. NYC DEP has built 6 green infrastructure assets here.

17,937

Properties in sewershed

69.5%

Legally eligible for on-site infiltration

34%

Stormwater exposure: Moderate or High

4%

Groundwater exposure: Moderate or High

What sets OH-002 apart

72 ft

Median ground elevation

89%

Average impervious cover per lot

1925

Median year built

1%

Properties over a historic stream or pond

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

Common solutions for Borough Park 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