What is a Certificate of Occupancy (CO) or TCO?

A Certificate of Occupancy (CO) is the key document issued by the NYC Department of Buildings that certifies a building is safe to occupy and specifies its legal use.

No one may legally occupy a newly constructed building or a space with a changed use until the DOB issues a CO or a Temporary Certificate of Occupancy (TCO). The document outlines the number of stories, maximum occupancy limits per floor, and the approved zoning use (e.g., residential, commercial, manufacturing).

Why it matters for NYC property owners

Occupying a building without a valid CO or TCO, or using a space contrary to what the CO allows (such as converting a commercial space into residential without approval), is illegal. The DOB can issue severe violations, issue Vacate Orders to force tenants out, and impose hefty daily fines. A missing or mismatched CO will also block property sales and refinancing, as title companies and banks require a valid CO before closing.

CO vs. TCO

There are two main types of certificates:

• Final Certificate of Occupancy (CO): Issued when all construction is completely finished, all required agency sign-offs (DOB, FDNY, DOT, etc.) are obtained, and there are no outstanding violations related to the project. It never expires unless major alterations are made.
• Temporary Certificate of Occupancy (TCO): Issued when a building is safe to occupy but some minor non-safety-related work or sign-offs are pending. A TCO is strictly temporary—usually valid for 90 days. It must be continuously renewed by the owner or expeditor until the Final CO is obtained. If a TCO expires, occupancy becomes illegal again.

What owners or managers should check

• If you are operating under a TCO, track the expiration date closely. Do not let it expire before renewing.
• If you own an older building (built before 1938), it might not have a CO. In this case, you must rely on a "Letter of No Objection" (LNO) or historical records to prove legal use.
• Ensure that the actual use of the space matches the CO. Operating a retail store in a space zoned only for manufacturing will trigger violations.

How D.O.B. Guard can help

D.O.B. Guard monitors your property's DOB profile 24/7. We alert you to new violations, Stop Work Orders, and complaint records that could complicate or block your ability to obtain a Final CO or renew your TCO.

Related Resources

• BIS vs. DOB NOW: Understanding NYC Building Systems
• DOB Violation Classes Explained

Disclaimer: This is general information only. For property-specific determinations on obtaining a Certificate of Occupancy, TCO renewals, or legalizing existing conditions, confirm with the relevant NYC agency (e.g., DOB) or consult a licensed architect or engineer. D.O.B. Guard does not provide architectural or engineering advice.

Frequently Asked Questions