How to Check an NYC Apartment’s Certificate of Occupancy

TL;DR: Search the exact address in both NYC DOB systems, open the applicable Certificate of Occupancy or Temporary Certificate of Occupancy, and compare its recorded building and floor use with the space being offered. A matching record is a useful screen, not a city guarantee that every room is legal, safe, or code-compliant today.

Before signing or sending move-in funds, check whether the apartment’s story matches the city’s occupancy record. Start with the Department of Buildings’ Find Building Data page, which links to DOB NOW and the older Building Information System (BIS). Search both systems, because their records are not interchangeable.

Your task is narrow: compare the recorded building use, floor use, permitted occupancy, and dwelling-unit count with the apartment you toured. If the record conflicts with the offer—or the owner cannot identify the record supporting an unusual space—pause before paying.

This is a screening workflow, not a legal opinion or a present-day safety inspection.

What a Certificate of Occupancy tells you

NYC DOB says a Certificate of Occupancy, or CO, states a building’s legal use and/or type of permitted occupancy. New buildings need a CO. An existing building needs a current or amended CO when later work changes its use, egress, or type of occupancy.

For a renter, the useful fields are usually:

the building’s approved use;
the floor or story;
the use listed for that floor;
the permitted number or type of dwelling units, where shown; and
the certificate’s status and issue date.

A CO may not name an individual apartment or validate every current bedroom, partition, or present-day condition. Use it to find conflicts. If a listing calls a lower-level room a bedroom but the applicable record lists that floor only for storage, that mismatch requires an explanation backed by a DOB record—not just a broker’s assurance.

A CO also does not answer every due-diligence question. It does not prove that the apartment is free of repair problems, active violations, pests, lead hazards, or unsafe conditions. Use the active DOB violations guide for that separate record check.

Search both DOB NOW and BIS

DOB’s systems overlap, but “DOB NOW means new” and “BIS means old” is too simple.

Open DOB’s official Find Building Data page.
Search the exact address in DOB NOW: Build and confirm the borough, house number, street, and Building Identification Number (BIN).
Search the same address or BIN in BIS.
Save the relevant certificate, floor-use details, identifying number, and the date you searched.

DOB’s current Certificate of Occupancy guidance gives a specific split for CO requests:

Request before March 1, 2021: use BIS and open “View Certificates of Occupancy.”
Request on or after March 1, 2021: use the DOB NOW Property Profile, then open the issued certificate’s “Certificate of Occupancy Details” and “Floor Use Records.”

The date applies to the CO request, not to every DOB filing. Transactions filed through DOB NOW appear there; eFiling and borough-office filings can remain in BIS during the systems transition. BIS is also important for 311-generated DOB complaints and records that may not appear in DOB NOW.

Do not stop at a property-summary screen. Open the certificate or certificate details and compare the actual floor-use information.

Read the record against the apartment

Use this five-part comparison:

Address and BIN: Make sure you have the correct building, not an adjoining lot or similarly numbered entrance.
Building use: Confirm that residential occupancy appears where the listing suggests it should.
Floor use: Match the apartment’s floor with the use recorded for that floor.
Dwelling-unit count: Where the certificate supplies one, compare it with the apparent building setup. A mismatch is a question, not proof by itself.
Certificate status: If the building relies on a Temporary Certificate of Occupancy, inspect the actual expiration date and the portions or floors it covers.

Do not infer more than the record says. A permit or job application is not, by itself, proof that work was completed, signed off, or approved for occupancy. A complaint is a reported concern, not a finding. A current CO, unexpired TCO, and DOB violation or complaint each answer different questions.

Use this decision table

| What you find | What it means | What to do next | |---|---|---| | Current CO and the recorded floor/use align with the offer | No obvious occupancy-record conflict | Save the record and continue the rest of your lease and safety review | | Current TCO | Occupancy may be allowed while final-CO items remain | Check its expiration date and whether the relevant floor/use is covered | | No CO for a building built before 1938 | The building may be exempt, but the absence proves neither legality nor illegality | Check for later alterations and ask whether DOB issued a Letter of No Objection | | Floor, use, or unit count conflicts with the offer | The listing and public record do not tell a consistent story | Ask for the applicable DOB record and resolve the conflict before signing or paying | | Only an owner explanation, permit, or pending job appears | Occupancy approval has not yet been verified | Do not treat it as equivalent to a CO, unexpired TCO, or applicable LNO |

Temporary Certificates of Occupancy

DOB may issue a Temporary Certificate of Occupancy, or TCO, when it determines that a property is safe to occupy even though outstanding items remain before a final CO can be issued. DOB says TCOs typically expire 90 days after issuance and may be renewed, but the only date that matters for your decision is the expiration date on the actual certificate.

If a building relies on a TCO:

confirm that it has not expired;
read the certificate or schedule for the covered floor and use;
ask management for the current renewal or final-CO status; and
save the certificate you reviewed.

Do not describe a TCO as covering a specific apartment unless the document actually does so. Its schedule may identify portions or floors rather than an individual unit.

Pre-1938 buildings and Letters of No Objection

A missing CO does not automatically mean an older apartment is illegal. DOB says buildings built before 1938 were not required to have a CO unless later alterations changed the use, egress, or occupancy.

That later-alteration exception matters. Check BIS and DOB NOW for alteration filings and occupancy records rather than stopping at the building year.

If the building is exempt from the CO requirement, a DOB borough office may issue a Letter of No Objection (LNO) confirming the building’s relevant legal use. An LNO is not automatically unit-specific. Ask to see the document and compare its stated building or floor use with the offered space.

Use this question:

“I could not find a current CO for this address. Is the building exempt because of its pre-1938 history, and has DOB issued a Letter of No Objection confirming the residential use relevant to this apartment?”

“No CO found” is a prompt to investigate—not a pass or a failure.

Basement, cellar, attic, loft, and subdivided spaces

Unusual spaces deserve an earlier records check because the listing label may not match the legal use.

HPD distinguishes a basement, which has at least half its height above curb level, from a cellar, which has more than half its height below curb level. HPD says basement or cellar occupancy requires minimum standards for light, air, sanitation, and egress plus DOB approval. It also says cellars in one- and two-family homes cannot be lawfully rented.

DOB lists possible illegal-conversion warning signs such as:

a basement, cellar, attic, garage, or industrial-looking space offered as a dwelling;
unusual subdivisions, padlocked rooms, or limited exits;
missing or unusually small windows;
extension-cord or improvised electrical setups;
no exact address, lease, mail delivery, or ordinary utility arrangement; and
pressure for cash while records or terms remain vague.

Any one sign is a reason to verify further; several strengthen the reason to pause. None proves illegality by itself. For a below-grade unit, pair this occupancy review with the NYC flood-risk check and the apartment fire-safety checklist.

Check complaints, violations, and vacate orders separately

After the CO review, search the building’s other records without treating them as the same thing:

BIS and DOB NOW: DOB complaints, violations, inspections, job filings, permits, and occupancy documents.
HPD Online: HPD complaints, housing-maintenance violations, registration information, and vacate orders.

A complaint records that someone reported a concern. A violation reflects an agency citation. A vacate order is a separate and more serious record. For alteration work, review the filing status and any applicable sign-off or occupancy record; do not assume a permit means completed work is approved for occupancy.

What to ask before signing or paying

Tie your question to the exact record:

“Before I sign or send move-in funds, please identify the current DOB record supporting the residential use shown for this apartment. I found [record or mismatch] for [floor/use]. Can you send the applicable CO, unexpired TCO, or—if the building is exempt from the CO requirement—Letter of No Objection?”

A useful answer points to a city record and explains the address, floor, use, and status. An owner’s or broker’s explanation by itself is not city approval.

Resolve an apparent mismatch before signing or sending a deposit, first month’s rent, or other move-in funds. If the warning signs are visible before you apply, investigate before paying an application fee.

A practical pre-signing workflow

[ ] Confirm the exact address, apartment number, entrance, and BIN.
[ ] Search the address in DOB NOW and BIS.
[ ] Open the applicable CO, TCO, or floor-use details—not only the summary page.
[ ] Compare building use, floor use, dwelling-unit count, and certificate status with the offer.
[ ] For a pre-1938 building with no CO, check later alterations and ask about an LNO.
[ ] Review DOB and HPD complaints, violations, and vacate orders separately.
[ ] Save the records, search date, and management’s written response.
[ ] Resolve material conflicts before signing or sending move-in funds.

RentReboot can help you discover matching apartments quickly. It cannot certify legal occupancy, interpret every DOB filing, or inspect present conditions. Use alerts for discovery and official city records for the address check.

Certificate of Occupancy FAQ

Does every NYC apartment building have a CO?

No. DOB says a building built before 1938 may be exempt unless later alterations changed its use, egress, or occupancy. An exempt building may have a Letter of No Objection confirming legal use.

Does a matching CO prove that my apartment is legal and safe?

No. It helps you screen recorded building and floor use for conflicts. It may not validate every current room or bedroom layout, and it does not prove present habitability, repair quality, or the absence of violations.

Is a Temporary Certificate of Occupancy enough?

A current TCO can allow occupancy while final-CO items remain. Read its expiration date and the portions or floors it covers. Do not assume an expired TCO or unrelated floor schedule covers the offered space.

Is every basement apartment illegal?

No. HPD says basement occupancy can be lawful only when required conditions are met and DOB has approved the residential use. Cellars in one- and two-family homes cannot be lawfully rented.

What if the listing floor conflicts with the CO?

Pause and ask management to identify the DOB record supporting the offered use. Do not treat a text explanation, permit, complaint status, or pending job application as occupancy approval.

Where do I report a suspected illegal conversion?

NYC311 has a Building Conversion or Occupancy Complaint process for past work or occupancy that may lack DOB approval. It routes active construction complaints separately, and immediate danger should be reported through the emergency channel stated by NYC311. Check the live NYC311 page for current filing options.

Bottom line

Search both DOB systems, open the actual occupancy record, and compare the recorded building and floor use with the apartment being offered. A coherent record lets you continue the rest of your due diligence. A conflict means pause, get the applicable city document, and resolve it before signing or paying.

👉 Set up RentReboot alerts to find NYC apartments that match your search, then run this official-record check when a listing becomes a serious contender.

Need the rest of the address record? The NYC apartment and building history lookup connects HPD complaints and violations, DOB jobs and permits, bedbug filings, and the limited HCR rent-history path without replacing this focused occupancy check.

General information, not legal advice. Official systems and individual records can change; recheck the live agency pages and the exact address before relying on them.

Sources

Reviewed August 16, 2026.