Methodology & sources

Everything on this site is derived from public records with deterministic, re-runnable scripts. No scraping of listing sites, no models guessing — just the paper trail, joined carefully.

What a page actually claims

A building page says a building appears on official rent-stabilization records — never that a given apartment “is rent stabilized.” Building-level records cannot answer unit-level questions: stabilized and market-rate units routinely coexist in one building, and owner filings contain errors and lapses. The only definitive answer for a specific unit is an official rent history from NYS Homes & Community Renewal, which every page links to.

Sources

• DHCR building registration lists — published by the NYC Rent Guidelines Board from NYS HCR data. We use the 2024-registration lists (posted December 2025, all five boroughs) and historical list appearances 2007–2013. These are the official “buildings containing stabilized units” rosters.
• Property-tax bills — owners are billed per rent-stabilized unit, so their tax bills disclose a per-year stabilized-unit count. We use JustFix’s extraction covering 2018–2024 and the taxbills.nyc project’s 2007–2017 series. Counts are owner-reported.
• PLUTO (NYC Dept. of City Planning, version 26v1) — addresses, coordinates, unit totals, year built, ownership, and tax-lot structure for every lot in the city.

How the dataset is built

1. Every building that appears in any source becomes a record, keyed by its BBL (borough-block-lot, the city’s permanent building ID) — 54,665 buildings.
2. The 2024 DHCR borough lists are extracted from the published PDFs; extracted row counts match the published totals exactly (50,879 rows → 47,187 unique buildings).
3. Tax-bill unit counts are joined by BBL, with condominium billing lots rolled up to the building. 98.6% of records join PLUTO directly; the remainder resolve through the prior-lot field or condo rollup, and 125 records (0.2%) lack coordinates.
4. Nothing is imputed. A year with no filing shows as a blank, not a zero, and pages say so.

Known limitations

• Owner-reported counts lapse and reappear; a missing year is weak evidence of anything.
• Historical DHCR list coverage in this build is 2007–2013 plus 2024 — years between may show tax-bill evidence only.
• Alternate addresses of one building resolve to the same BBL; the page shows the primary.
• 421-a / J-51 stabilization can expire with the tax program; the page flags the program where the record shows one.

Attribution

NYC Dept. of City Planning (PLUTO) · NYC Rent Guidelines Board / NYS HCR (building lists) · JustFix and taxbills.nyc / talos (tax-bill unit counts). This site is independent and not affiliated with any agency.