What is a Certificate of Occupancy and why does it matter for rental properties in NYC?

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A Certificate of Occupancy (CO) is an official document issued by the NYC Department of Buildings that certifies a building or unit is legally approved for a specific type of use.

Why the Certificate of Occupancy matters for rental properties:

A landlord cannot legally rent out a residential unit without a valid CO that authorizes residential use
Renting a unit without a valid CO — or one with a CO that specifies a different use (e.g., commercial) — is illegal and can result in fines
Tenants in units without a valid residential CO may have grounds to withhold rent or void the lease

How to check a property's Certificate of Occupancy:

Search the NYC Buildings Department website (DOBNow) using the property address
The CO lists the legal use, number of units and occupancy classification for the building

Common CO issues in NYC rental properties:

Converted basement apartments — many NYC basement apartments lack a CO for residential use because they do not meet light, air or egress requirements
Illegal subdivisions — landlords who split one legal unit into two without permits operate without a valid CO for the new configuration
Building additions — any significant structural change requires an updated CO

For tenants: If you discover your apartment lacks a valid residential CO, document this and seek legal advice — you may be entitled to a rent abatement or lease termination without penalty.