Sewershed CI-005 · NYC DEP Combined Sewer Overflow Tributary Area
CI-005 - East Flatbush, Brooklyn
Properties in this area share the CI-005 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 Flatbush, Brooklyn specifically.
CI-005 is a combined sewer area covering 13,975 properties in East Flatbush, Brooklyn. Flood Form rates 51% of them Moderate or High for stormwater exposure, and 15% for groundwater. 78% of lots have yard area that legally qualifies for on-site infiltration. Ground elevation is typically 29 ft. The median building dates to 1931. 6% of parcels sit over a historic stream or pond. According to NYC DEP green infrastructure records, this sewershed drains to Jamaica Bay and Tributaries. NYC DEP has built 1,321 green infrastructure assets here.
13,975
Properties in sewershed
77.6%
Legally eligible for on-site infiltration
51%
Stormwater exposure: Moderate or High
15%
Groundwater exposure: Moderate or High
What sets CI-005 apart
29 ft
Median ground elevation
85%
Average impervious cover per lot
1931
Median year built
6%
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 Flatbush 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
- 26W-003Brownsville12,515 properties · 41% with Moderate or High stormwater exposure
- CI-004Flatlands32,638 properties · 46% with Moderate or High stormwater exposure
- CI-006Flatlands2,349 properties · 43% with Moderate or High stormwater exposure
- 26W-004New Lots4,058 properties · 45% with Moderate or High stormwater exposure
- RH-005Bedford-Stuyvesant8,460 properties · 43% with Moderate or High stormwater exposure
- NCB-015Bushwick19,026 properties · 38% with Moderate or High stormwater exposure
Want to see where your specific property stands?
Get Your Property’s Flood Form