Sewershed NCM-034 · NYC DEP Combined Sewer Overflow Tributary Area
NCM-034 - Turtle Bay, Manhattan
Properties in this area share the NCM-034 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-034 is a combined sewer area covering 131 properties in Turtle Bay, Manhattan. Flood Form rates 66% of them Moderate or High for stormwater exposure, and 15% for groundwater. 67% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 37 ft. The median building dates to 1930. 16% of parcels sit over a historic stream or pond.
131
Properties in sewershed
67.2%
Legally eligible for on-site infiltration
66%
Stormwater exposure: Moderate or High
15%
Groundwater exposure: Moderate or High
What sets NCM-034 apart
37 ft
Median ground elevation
95%
Average impervious cover per lot
1930
Median year built
16%
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.
Nearby sewersheds
- NCM-032Turtle Bay156 properties · 46% with Moderate or High stormwater exposure
- NCM-036Upper East Side1,944 properties · 56% with Moderate or High stormwater exposure
- NC-017Murray Hill105 properties · 61% with Moderate or High stormwater exposure
- NCM-005Lenox Hill392 properties · 38% with Moderate or High stormwater exposure
- NCM-037Midtown385 properties · 54% with Moderate or High stormwater exposure
- NCM-038Murray Hill118 properties · 80% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form