NYC Certificate of Occupancy (C of O): What It Is and Why It Matters

A Certificate of Occupancy — usually written as C of O or CO — is the city document that says a building can legally be lived in or used for the purpose stated on it. Issued by the Department of Buildings. Every NYC building over 3 stories or with more than one unit needs one. If a building doesn't have a valid C of O, technically nobody is supposed to be living there.

Why it matters

• Legal residency. Renting an apartment in a building without a valid residential C of O can affect your ability to enforce the lease, get a renter's insurance claim paid, or even register kids for the zoned school.
• Mortgage approval. Most NYC lenders refuse to fund a purchase in a building without a Final C of O. A Temporary C of O might still close, but it'll get scrutiny.
• Building-class risk. If the C of O says "Office (Class B)" but the apartment is being marketed as a residential loft, that's a live-work situation that may not be legal under current zoning.

Final vs Temporary C of O

There are two everyday flavors:

Final C of O

Issued when construction is complete and DOB has signed off on every required inspection. The strongest possible signal — building is fully approved for the listed use. No expiration.

Temporary C of O (TCO)

Issued when most of the building is safe and habitable but a few items are still in progress (e.g. final landscaping, last-floor punch list). TCOs typically have a 90-day expiration and must be renewed until the Final C of O is granted.

Most new-construction NYC condos sell on a TCO for the first 6-18 months. That's normal. The risk is when TCOs keep getting renewed for years — that means the developer can't get the Final and there are unresolved DOB issues.

When a C of O isn't required

Pre-1938 buildings (most NYC walk-ups) didn't need a C of O when built. They run on a "Letter of No Objection" from DOB, which states the legal use even though the building predates the C of O system. If your prospective apartment is in a small pre-1938 walk-up, the absence of a C of O is normal — but you should still see a Letter of No Objection on file.

Red flags worth checking

• No C of O AND building was built after 1938. Likely an unresolved DOB issue. Don't sign without an attorney.
• TCO expired and not renewed. Sometimes a paperwork lapse, sometimes a sign the developer is stuck on the punch list. Ask.
• C of O lists "Office" or "Manufacturing" but unit is being rented as residential. Loft-law gray-zone. Get an attorney involved before signing — a tenant in an unlawful conversion has limited rights.
• Number of units on C of O is fewer than the building actually has. Likely an illegal subdivision. The "extra" units may not be habitable under code.

How to check the C of O on a building

Search the address on NYC Property Audit — the Pro report's Building Profile section pulls C of O status, issue date, listed use, and unit count from DOB records. We surface mismatches between the C of O and PLUTO's recorded use as an analyst note so you don't have to spot them yourself.