821A Union Street, Brooklyn
Co-op · 4 units · built c. 1920 · Block 954, Lot 61.
Building permits
- Alteration, filed Dec 18, 2025, estimated cost $40K, described as “Install new split a.c. System at APT#3 of existing 4-story building with mechanical work as per plans filed here with. No change in use, egress or certificate of occupancy.”
- Alteration, filed Feb 11, 2020, estimated cost $16K, described as “Exterior renovation of existing apartment on the 4TH floor and penthouse. Structural work to create 2 new skylight openings only. No change of use, occupancy or egress”
- Alteration, filed Dec 20, 2019, estimated cost $10K, described as “Herewith filing for replacement and installation of plumbing fixtures, as per plans submitted.”
Property taxes
- Assessment
- $1,102,050
- 2026–27 tax
- $12,726
- Market value (city estimate)
- $2,449,000
- Taxable value
- $142,285
- Assessed land
- $12,600
- Assessed improvements
- $1,089,450
Tax breaks
- Co-op and condo abatement, with no end date, a $4,973 credit this tax year.
Zoning
R6A: floor area ratio 2.93 built, 3.00 allowed by base zoning.
Flood zone
Current FEMA flood map: zone X, minimal flood hazard.
Recent sales
- Jan 28, 2021: $1,200,000
- Aug 19, 2019: $2,167,000
- Jun 2, 2016: $1,150,000
Open-market sales since 2016, from the Department of Finance’s sales files.