What is Certificate of Occupancy (C of O)?
Every building constructed after 1938 in NYC is required to have a Certificate of Occupancy. The C of O specifies:
- The building's legal use (residential, commercial, manufacturing, or mixed)
- The occupancy classification (assembly, business, educational, etc.)
- The number of stories, units, and maximum occupancy
- Whether the certificate is final (permanent) or temporary
A temporary C of O is issued for a limited period, usually during ongoing construction. It must be renewed before expiration — failure to do so can result in a vacate order.
Using a building inconsistently with its C of O is a violation of the NYC Building Code and can result in DOB violations, fines, and enforcement action. This is particularly common with illegal conversions (e.g., converting a cellar to a dwelling unit).
RegWatch shows C of O status for every NYC property, cross-referenced with current zoning and permit data. Search C of O records →
Frequently Asked Questions
What is a Certificate of Occupancy in NYC?
A C of O is a DOB document certifying a building's legal use and occupancy. It specifies what activities are permitted and how many occupants are allowed.
Do all NYC buildings need a C of O?
Buildings constructed after 1938 are required to have one. Older buildings may have a Letter of No Objection instead.
What happens if a building doesn't have a C of O?
Operating without a valid C of O can result in DOB violations, fines, vacate orders, and complications with financing and insurance.
How do I look up a C of O?
Search any NYC address on RegWatch to see the C of O status, or check DOB's BIS system directly.
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