For buildings that require one, a Certificate of Occupancy is the Department of Buildings record that says how the building may legally be used and occupied. It is often shortened to CO.
The CO states how a building or space may legally be used, what occupancy classification it is approved for, and how many people it may hold. It is the document the city, lenders, buyers, and tenants rely on to confirm that a use is legal. For a new building, no one can move in until the CO, or a temporary version of it, has been issued.
Some older New York City buildings do not have a CO. When there is no CO, the same legal question still applies, but the answer comes from other city records.
What a Certificate of Occupancy is
A Certificate of Occupancy is the document the Department of Buildings issues to describe a building's legal use, its permitted occupancy, and the floor-by-floor occupancy information the city has approved.
Legal use is what the building or space is approved for, such as residential, commercial, or a mix of the two. Occupancy classification is the building-code category that helps determine how a space may be used and how many people it may hold. In residential buildings, the CO also shows dwelling units, meaning the separate legal apartments or residences in the building.
A new building needs a CO before anyone moves in. An existing building needs a new or amended CO when work changes its use, egress, or occupancy. Egress means the building's exits and the routes that lead to them.
A final CO has no expiration date. It stays valid until later work changes the building's use, egress, or occupancy and calls for a new or amended one. A property occupied without the CO it should have can draw violations, and in some cases a vacate order that requires occupants to leave.
What a CO shows
A Certificate of Occupancy is organized into a few parts. It opens with general building information, then sets out the occupancy classification, the legal use, and technical details about the structure. The most detailed part is the Use and Occupancy Schedule, a table that states how each floor may legally function.
For each floor, the schedule shows the permitted use, the occupancy classification, the number of people the floor may hold, and, in residential buildings, the number of dwelling units. The number of people a space may hold is its occupant load.
On any CO, the issue date shows how current it is, and the per-floor uses show what is legal where. That per-floor detail matters in a mixed-use building, where the ground floor may be commercial and the floors above residential. The heading also shows whether the document is a final CO or a temporary one.
Temporary and final certificates
The two CO documents owners most often encounter are the final Certificate of Occupancy and the Temporary Certificate of Occupancy.
A final CO is the permanent record, issued once the work is complete, the required inspections have passed, and there are no open applications or violations on the property. A Temporary Certificate of Occupancy, or TCO, is issued when a building or space is safe to occupy but still has open items, such as unfinished common areas, incomplete work outside the occupied area, or paperwork that has not cleared.
A TCO usually expires ninety days after it is issued, and it can be renewed while work continues toward a final CO. Renewal requires DOB review, and the TCO request must have the required temporary or final inspection sign-offs. A space left unoccupied for more than thirty days needs a new TCO before anyone can move back in.
The Department recommends against closing on a purchase before a final CO is in place. A building can run on renewed TCOs for a long time, and a TCO can lapse if the work behind it stalls. A buyer or lender relying on a TCO is relying on an approval with an expiration date.
Buildings without a Certificate of Occupancy
Not every New York building has a CO. The city did not generally require one until 1938, so a building constructed before then may have none, and it is not required to obtain one unless later work changed its use, egress, or occupancy.
When a building has no CO, the city can confirm its legal use through other records. The common route is a Letter of No Objection, a statement from the Department's borough office that it has no objection to a stated use. A Letter of No Objection is accepted in place of a CO for many purposes, though it is not a substitute for one.
The Department will issue a Letter of No Objection only when the use stays within the same zoning use group and building-code occupancy group, and the occupant load and egress are unchanged. A change to the zoning use group or occupancy group falls outside that path and calls for a new CO.
For some older multiple dwellings, an I-card can help document legal occupancy. An I-card is an older housing-agency inspection record that may show the building's layout and legal units.
The three documents side by side
| Document | What it is | When it is used | How long it lasts |
|---|---|---|---|
| Final CO | The permanent record of a building's legal use and occupancy | New construction and CO-changing work, once complete | No expiration, until later work changes use, egress, or occupancy |
| Temporary CO (TCO) | A time-limited approval to occupy while final items are finished | A building that is safe to occupy but has open items or paperwork | About 90 days, renewable while work continues and renewal requirements are met |
| Letter of No Objection | A statement that the city has no objection to a building's stated use | A building, often pre-1938, that has no CO on file | Stands for the use it records, and a change in use group or occupancy group calls for a new CO |
When a building needs a new or amended CO
A building needs a new or amended Certificate of Occupancy when work changes its legal use, its occupancy, its egress, the number of dwelling units, or the number of stories. That kind of work is filed with the Department as an Alteration-CO, the job type that ends in a new or amended CO.
Work that leaves the legal record in place is filed as an Alteration and ends in a Letter of Completion, which records that the permitted work is done and that no new CO was required.
Many renovations do not change the CO. A kitchen and bath gut, a layout change, or new wiring usually leaves the building's use and occupancy as they were. The CO is involved when the work changes what the building legally is.
Why the CO matters
The CO controls whether a space can be legally used. Without the CO it should have, a building cannot be legally occupied, and a use that contradicts the CO can draw a violation or a vacate order.
It also matters in most property transactions. A lender will usually want to see a current CO or TCO before closing a loan, a buyer's attorney will check that the CO matches the building's actual use, and a commercial tenant will want to confirm that the space is approved for the intended use before signing a lease. An open or mismatched CO can hold up a sale or financing until it is resolved.
How to look up a building's CO
Certificates of Occupancy are public records, so anyone can look one up.
For records on or after March 1, 2021, search the property address in the DOB NOW public portal, open the Property Profile page, and select Certificate of Occupancy to see the CO details and floor-use records. Older records sit in the Department's Building Information System, known as BIS, which is searchable by address or by the building's identification number.
If a building has no CO on file and predates the requirement, the next step is to request a Letter of No Objection from the borough office to confirm its legal use.
The Certificate of Occupancy is the legal baseline for a building. It tells you what the building may be used for, how it may be occupied, and when a renovation, sale, lease, or financing may need closer review. Before changing a space, buying one, leasing one, or lending against one, the CO is the place to start.