The Certificate of Occupancy (C of O) is one of the most important — and most misunderstood — documents in NYC real estate. It defines what a building can legally be used for, and discrepancies between the C of O and actual use create serious legal and financial problems.
What Is a Certificate of Occupancy?
A Certificate of Occupancy is a document issued by the NYC Department of Buildings certifying that a building complies with applicable building codes and is safe for the approved use. It specifies:
- The permitted use of each floor and space (residential, commercial, manufacturing, etc.)
- The maximum number of occupants
- The building's construction classification
- Compliance with fire and safety codes
Why the C of O Matters
Using a building in a way that does not match its C of O is a violation — and a common one. Examples:
- Converting a commercial space to residential without amending the C of O
- Operating a restaurant in a space certified for retail
- Using a cellar as a dwelling unit (extremely common and extremely dangerous)
- Exceeding the certified occupancy of a space
Violations for use contrary to the C of O can result in DOB violations, fines, vacate orders, and inability to obtain or renew permits.
Types of Certificates
- Certificate of Occupancy: Permanent approval for new buildings or major alterations
- Temporary Certificate of Occupancy (TCO): Time-limited approval (90 days, renewable) while minor items remain incomplete. Common for new construction while punch list items are finished.
- Letter of No Objection (LNO): For buildings built before 1938 that may not have a C of O on file. The DOB issues an LNO confirming the legal use.
How to Check a Property's C of O
You can look up the Certificate of Occupancy through DOB NOW (newer certificates) or the legacy BIS system (older records) by searching the property address or BIN. RegWatch also displays C of O information in the property profile. For a quick check, use our free property search to get basic building data, then sign up free for the full profile including C of O status.
Getting or Amending a C of O
To obtain a new C of O or amend an existing one:
- File plans with the DOB (typically through a registered architect or professional engineer)
- Obtain required permits
- Complete construction in accordance with approved plans
- Pass all required inspections
- Submit the C of O application
- DOB reviews and issues the certificate
This process can take months to years depending on the complexity of the project and the DOB's workload.
C of O Red Flags in Real Estate Transactions
- No C of O on file: Common for pre-1938 buildings. Not necessarily a problem, but verify the legal use.
- Expired TCO: The building is technically operating without a valid certificate. This can delay closings and affect insurance.
- C of O does not match actual use: A major red flag. The buyer may inherit liability for bringing the building into compliance.
- Pending C of O amendment: Indicates ongoing work that must be completed to legalize the current use.