5723 21st Avenue, Brooklyn
Two-family · built 1960 · Block 5501, Lot 1.
Building permits
- Alteration, filed Jun 30, 2026, estimated cost $581K, described as “Herewith filing for horizontal enlargement and interior renovation. (3) three story with cellar, (1) one family building. No change in use, egress or occupancy”
- Alteration, filed Jan 7, 2026, estimated cost $127K, described as “Application filed herewith for interior renovation at first andsecond floor, with replacement facade, windows, roof (2) two story, (2)two family building.no change in use, egress or occupancy.”
Property taxes
- Assessment
- $93,780
- 2026–27 tax
- $10,819
- Market value (city estimate)
- $1,563,000
- Taxable value
- $54,525
- Assessed land
- $21,000
- Assessed improvements
- $72,780
Zoning
R5: floor area ratio 0.73 built, 1.50 allowed by base zoning.
Flood zone
Current FEMA flood map: zone X, minimal flood hazard.
Recent sales
- Jul 10, 2025: $2,600,000
Open-market sales since 2016, from the Department of Finance’s sales files.