How Buildings Are Rated
Every NYC building gets a rating — red, yellow, or green — based on public records from NYC agencies (HPD, DOB, and 311). Three weighted factors set the base score. A short list of penalties and hard caps can pull it down from there.
Nothing is estimated. If a factor can't be measured for a building, it's dropped and the others are re-weighted rather than filled in with a guess.
Violations
(40%)Open HPD violations, weighted by severity and normalized per unit — 10 violations across 100 units is a very different building from 10 across 5. Open DOB violations and active stop-work orders reduce this same subscore, as does a low resolution rate. Violations spread across many units count for more than the same number stacked in one apartment.
How NYC HPD classifies violations by severity:
- Class C — Immediately hazardous. Lead paint, no heat, gas leaks, broken smoke detectors. Landlord must fix within 24 hours. Weighted three times a Class A.
- Class B — Hazardous. Mold, leaks, broken windows, pest infestations. Landlord must fix within 30 days. Weighted one and a half times a Class A.
- Class A — Non-hazardous. Cracked paint, minor maintenance issues. Landlord must fix within 90 days. A high count of open Class A violations is a strong signal of general neglect.
Complaints
(30%)Tenant complaints about conditions inside the building over the last 12 months, measured per unit rather than as a raw count. Complaints about the street, sidewalk, parked cars, vendors, or the surrounding blocks are shown on every report but never affect the rating — a landlord isn't responsible for the block. A building with no complaints but a poor violation record doesn't get full credit here: silence next to open hazards usually means tenants stopped calling.
Responsiveness
(30%)How reliably and how quickly violations get resolved after they're filed — resolution rate, median days to fix, and how much of the last 24 months' filings are still open. When a building has too little history to measure this honestly, it isn't guessed at: the remaining two factors are re-weighted to carry the full rating instead.
What else pulls a score down
These aren't weighted factors — they're deductions taken off the base score when the record shows them.
- Unpaid ECB fines. Judgment debt owed to the city on this building. Scales with the balance, up to 20 points.
- Elevator and certificate problems. Open elevator violations, inspections more than a year overdue, and expired certificates of occupancy.
- 311 call density. Building-specific 311 volume relative to its size — not street or block calls.
- Alternative Enforcement Program. A 20-point deduction while the city has the building in the program it reserves for its most distressed buildings.
Hard ceilings
Some findings are serious enough that a good record elsewhere shouldn't outvote them. These set a maximum the score can't rise above.
- Full vacate order. An open order to vacate the entire building caps the score at 25, no matter how the rest of the file reads.
- Partial vacate order. An open order on part of the building caps the score at 77. A vacate order lifted within the last two years still costs 10 points.
- Structural distress. Heavy DOB violation counts, or immediately hazardous violations affecting a tenth of the units, cap the score at 50.
- Class C concentration. More than two immediately hazardous violations per unit floors the violation subscore outright.
Rating Scale
No major concerns on record. HPD/DOB records are quiet and complaints resolve quickly.
Mixed signals worth investigating — open violations, unresolved complaints, or a pattern of slow responsiveness. Not a dealbreaker, but ask questions.
Serious unresolved issues on record — hazardous violations, chronic complaints, or a landlord history that warrants real caution.
The score sets the starting tier, but a few findings override it directly. An active vacate order or a landlord on the city's watchlist within the last three years reads red. Any open violation, 12 or more complaints inside the building in a year, or heavy 311 volume pulls a green building to yellow — a quiet score doesn't get to outrank an open hazard.
Disputing a rating
Think a rating is built on incorrect data? Tell us — we'll trace it back to the source record and correct anything we got wrong.
Ratings are updated regularly as new violation and complaint data is published by NYC agencies. Ratings are estimates based on public records and should not be the sole basis for housing decisions.