550 Union Street, Brooklyn
Industrial · built c. 1910 · Block 440, Lot 29.
Building permits
- Alteration, filed Sep 3, 2026, estimated cost $1K, described as “Installation of temporary heavy duty sidewalk shed as per plans. No change in use, egress or occupancy. Sidewalk shed shall comply with chapter #33 of 2022 the NYC building code. Live load 300PSF.”
- Alteration, filed Mar 11, 2026, described as “Construction fence”
- Major Renovation — Conversion, filed Oct 1, 2025, estimated cost $3.3M, 8 units added, 5 stories, described as “Alteration CO application as-of-right conversion of existing 2 story commercial building into a residential R-2 building with horizontal & vertical enlargement for 8 D.U.'s, 5 stories & Cellar. New egress stairs & building to be fully…”
Property taxes
- Assessment
- $248,850
- 2026–27 tax
- $24,223
- Market value (city estimate)
- $553,000
- Taxable value
- $223,290
- Assessed land
- $32,400
- Assessed improvements
- $216,450
Zoning
M1-4/R6A: floor area ratio 1.26 built, 3.00 allowed by base zoning.
Flood zone
Current FEMA flood map: zone X, minimal flood hazard.
Recent sales
- Jun 27, 2025: $4,000,000
- Feb 28, 2024: $4,000,000
- Jul 27, 2021: $2,000,000
Open-market sales since 2016, from the Department of Finance’s sales files.
Board and land use applications
- Gowanus Neighborhood Plan (City Planning 2018K0382): Zoning map change, Zoning text change, City map change, Urban development action area, Completed, decided Dec 6, 2021. The Gowanus Neighborhood Plan is a shared, long-term vision for a thriving neighborhood. It looks to identify strategies for an equitable, resilient and sustainable Gowanus, with more local jobs and housing. The Plan supports community…
In the news
Demolition Progresses For New Residential Building At 544-550 Union Street in Gowanus, Brooklyn, New York YIMBY, Jul 27, 2026.