The building by the numbers
| Metric | Value |
|---|---|
| Residential condo units on the roll | 34 |
| Median DOF market value | $1,022,789 |
| DOF market-value range | $200,744 – $2,624,611 |
| Units over the $1M surcharge threshold | 18 (53%) |
| Top-unit surcharge if non-primary | $104,984 / year |
Every condo and co-op in New York is tested against the pied-à-terre surcharge on its DOF market value — the "Market Value" line on the Notice of Property Value (an income-derived Department of Finance figure), not the 45%-of-market assessed value on your regular tax bill. In 15 Union Square West, that test splits the building: 53% of units clear the $1,000,000 market-value threshold and owe a flat 4%–6.5% of their full market value for any year they are not someone's primary residence, while the rest owe nothing under Phase 1 (through June 30, 2028). Phase 2 re-tests everyone in 2028.
Sample units from the FY 2026–27 roll
| Unit | DOF market value | Assessed value | Est. surcharge if non-primary |
|---|---|---|---|
| Apt 8 | $200,744 | $90,335 | $0 — under threshold |
| Apt 22 | $707,843 | $318,530 | $0 — under threshold |
| Apt 12 | $1,025,326 | $461,397 | $41,013 / yr |
| Apt 10 | $1,280,082 | $576,037 | $51,203 / yr |
| Apt 34 | $2,624,611 | $1,181,075 | $104,984 / yr |
Owners in Flatiron/Union Square: 53% of units here test over the $1M threshold, so the surcharge reaches a real share of this building. The exemptions are real, though: a unit occupied >half the year by you or an immediate family member, or leased arm's-length for 12+ months, owes nothing. The main guide covers every rule; the free check below gives you your unit's exact numbers.
What's YOUR unit's DOF market value?
Free emailed report: official DOF market value (the surcharge base), assessed value, surcharge test, and — if you're over the line — what a 12-month lease or a sale would look like. Usually within the hour.
Check My Unit — FreeFigures from the public NYC DOF assessment roll (dataset 8y4t-faws), FY 2026–27. Educational information, not tax or legal advice. The surcharge is the flat statutory rate applied to the unit's full DOF market value once it exceeds the $1M threshold. Unit designations are public record; no ownership information is shown.