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Sewershed NCM-032  ·  NYC DEP Combined Sewer Overflow Tributary Area

NCM-032 - Turtle Bay, Manhattan

Properties in this area share the NCM-032 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 Turtle Bay, Manhattan specifically.

NCM-032 is a combined sewer area covering 156 properties in Turtle Bay, Manhattan. Flood Form rates 46% of them Moderate or High for stormwater exposure, and 17% for groundwater. 60% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 54 ft. The median building dates to 1910. 3% of parcels sit over a historic stream or pond.

156

Properties in sewershed

59.6%

Legally eligible for on-site infiltration

46%

Stormwater exposure: Moderate or High

17%

Groundwater exposure: Moderate or High

What sets NCM-032 apart

54 ft

Median ground elevation

95%

Average impervious cover per lot

1910

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 Turtle Bay 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