Certificate of Occupancy NYC: A Landlord's Guide to Rent Risk, Lookups, and Amendments

A New York City landlord went to court to collect rent. The building had 60 apartments. Its certificate of occupancy permitted 53.

The court did not bar the owner from collecting rent on the seven extra units. It barred the owner from collecting rent on the entire building — and the Appellate Division affirmed (GVS Properties v. Vargas, 59 Misc.3d 128(A) (App. Term 1st Dept 2018), aff'd 172 A.D.3d 466 (1st Dept 2019)).

Most New York City owners treat the certificate of occupancy as a closing document. Something the architect dealt with years ago, filed away, never looked at again. It is actually the document that defines what you are legally permitted to rent, to whom, and how many of them — and when it stops matching reality, the fines are the least of it. A certificate of occupancy violation in NYC runs $2,500, or $12,500 if you ignore the hearing. The rent exposure is one hundred percent of the rent roll.

This guide covers what your CO says, how to find it (most guides get this part wrong), what happens when it is wrong, when you need an amendment, and what to check before you hand a tenant a lease.

What Is a Certificate of Occupancy?

In the Department of Buildings' own words, a certificate of occupancy "states a legal use and/or type of permitted occupancy of a building." It is issued under Article 118 of the NYC Administrative Code, and for residential buildings with three or more units it interacts with the New York State Multiple Dwelling Law in ways that carry real financial consequences.

Two things owners routinely get wrong about it.

A final CO has no expiration date. If your building has a valid final CO and nothing about its use, egress, or occupancy has changed, it does not lapse and does not need renewing. A temporary certificate is an entirely different instrument, covered below.

Not every NYC building is required to have one. Buildings constructed before 1938 that did not require a CO at the time may legally continue without one — with a condition attached that catches owners off guard.

What Your Certificate of Occupancy Actually Tells You

The CO is not a formality. It is a specification sheet for what you may legally do with the building, and the contents are set by statute. Administrative Code §28-118.6 requires DOB to include the following:

One critical field is not on the statutory list but appears on the face of every NYC CO and in DOB's public data: the number of dwelling units. For a residential owner, that is the first thing to check and the most expensive thing to get wrong.

The five-point CO audit

Pull your CO and check these five things against what is actually happening in the building today:

1. Legal dwelling-unit count versus the number of units you are actually renting.
2. Use Group on each floor versus what each tenant actually does there.
3. Design occupant load per floor versus actual headcount.
4. The stipulations and conditions block — variances and declarations that run with the property.
5. Whether the document is a TCO or a final CO — and if it is a TCO, whether it is still in date.

This audit typically gets done once, at acquisition, and then never again. That is precisely how a mismatch develops: the building changes over twenty years, the document does not, and nobody compares them until a lender, a buyer, or a tenant's attorney does it first.

What Happens When Your Certificate of Occupancy Is Wrong

This is the part that almost no guide on this topic covers, and it is the part that costs the most.

The rent bar

Multiple Dwelling Law §302(1)(b) is one sentence long:

"No rent shall be recovered by the owner of such premises for said period, and no action or special proceeding shall be maintained therefor, or for possession of said premises for nonpayment of such rent."

In plain terms: no rent, and no nonpayment proceeding to chase it.

The Vargas facts are worth sitting with, because they are ordinary. The owner had substantially altered the building over time. It ended up with 60 apartments where the CO permitted 53. DOB declined to issue a corrected CO over fire-safety concerns involving a second means of egress. Seven units of drift, accumulated across years of alterations, and the result was a bar on collecting rent building-wide.

And the rent bar is only one of four consequences MDL §302 attaches to unlawful occupation. During the period of violation:

• Any mortgage on the property may be declared due at the lender's option
• No rent is recoverable and no nonpayment proceeding may be maintained
• The city may withhold water service, and the premises are deemed unfit for human habitation and are to be vacated
• DOB may issue a vacate order for a building occupied by more families than permitted or otherwise "occupied contrary to law"

The fines

Separately from the rent exposure, occupancy problems carry civil penalties enforced through OATH. These are the current figures from the Buildings Penalty Schedule at 1 RCNY §102-01:

There is a detail in that schedule worth understanding before you get one. Most DOB violations offer three ways to reduce or eliminate the penalty: cure it within 60 days for no penalty, take a pre-hearing stipulation for half, or prove correction at the hearing for half. The Class 1 certificate of occupancy charges are marked ineligible for all three. No cure, no stipulation, no mitigation. You pay $2,500, or you pay $12,500 for not showing up — and failing to appear is itself treated as a finding "in violation," which becomes the predicate that aggravates the next one. The mechanics of how these summonses work are covered in our guide to DOB violations.

Illegal conversions sit in a more severe tier. A dwelling occupied with three or more additional units beyond what the CO authorizes draws a $15,000 Class 1 penalty under §28-210.1 — and the schedule's own footnote specifies that the penalty "applies to each additional dwelling unit above the number authorized in the certificate of occupancy." A legal two-family converted to a four-family is a separate $5,000 charge. Continuing Class 1 illegal-conversion violations accrue an additional $1,000 per day, capped at $45,000. Note that this daily accrual is specific to illegal-conversion charges; the general Class 1 daily cap is $25,000.

How to Look Up Your Certificate of Occupancy

Certificates of occupancy live in two DOB systems, and which one holds yours is the part nearly every guide on this topic gets backwards.

The walkthrough:

1. Find your BIN and BBL. The BBL is ten digits — borough, then a five-digit block, then a four-digit lot. The BIN is a seven-digit Building Identification Number. This distinction matters: a single tax lot can contain several buildings, and the certificate of occupancy attaches to the BIN, not the lot. Both are free to look up through ZOLA or the NYC Property Information Portal.
2. Search DOB BIS. Enter the address, open the Property Profile, and select "View Certificates of Occupancy." For a CO that has been requested but not yet issued, check "Jobs/Filings" instead.
3. Search the DOB NOW public portal. Same idea — address search, then Certificate of Occupancy.
4. Use NYC Open Data for portfolios. There are two datasets mirroring the same split, which is useful if you are pulling many BINs at once.

If nothing comes up, do not conclude you have no CO. DOB's Open Data certificate of occupancy records begin on July 12, 2012. They are not a historical archive. A building whose most recent CO was issued in 1974 will return zero rows in the public datasets while holding a perfectly valid CO on file as a scanned PDF in BIS. One more trap worth knowing: the address fields in those datasets are documented as the owner's address, not necessarily the building's. Match on BIN or BBL, never on the address string.

Finally, a note on where COs are not. They are Department of Buildings records. ACRIS is the Department of Finance register for deeds, mortgages, liens, and other recorded instruments — it has no certificate of occupancy document type in its index, and it does not cover Staten Island at all. If you are searching ACRIS for your CO, you are in the wrong system.

Pulling the document is the easy part. Reading a scanned 1962 certificate against a 2026 rent roll, and knowing which discrepancies are cosmetic and which ones bar rent, is where this gets difficult.

Temporary vs. Final Certificate of Occupancy

A final CO has no expiration date. A Temporary Certificate of Occupancy (TCO) is issued when a building or a portion of it is safe to occupy but not yet complete. TCOs typically run 90 days, must be renewed until a final CO issues, and under the Multiple Dwelling Law cannot be renewed beyond a total of two years from original issuance.

Three sources govern the duration, and they say slightly different things worth reconciling. Administrative Code §28-118.15 leaves the validity period to the commissioner rather than fixing it in statute. DOB's practice is roughly 90 days. And MDL §301(4) sets a hard outer wall for multiple dwellings: renewals "shall not extend, together with such renewals, beyond a total period of two years from the date of its original issuance."

Living on TCO renewals is not unusual. In our analysis of DOB's certificate of occupancy records, roughly two-thirds of all DOB NOW certificate of occupancy activity is TCO renewal rather than initial or final issuance. It is the norm, not an edge case.

Pre-1938 Buildings and the Letter of No Objection

Buildings built before 1938 that did not require a CO at the time may legally continue without one — provided there has been no change in the existing use or occupancy classification. To document legal use where no CO exists, owners request a Letter of No Objection (LNO) from the DOB borough office where the property is located.

The statutory basis is Administrative Code §28-118.3.4, which permits pre-1938 buildings to continue in use "provided there is no change in the existing use or occupancy classification." The Multiple Dwelling Law adds its own grandfather provisions for certain pre-1929 Class B dwellings and old-law tenements.

You will typically need an LNO the first time a lender, title company, buyer, or commercial tenant asks for the CO and there is not one. Pre-1938 owners may also apply for a CO voluntarily under §28-118.3.4.1, though this requires compliance with retroactive Code requirements and no pending violations or orders against the building.

Mixed-Use Buildings: When Your Tenant's Use Becomes Your Problem

If you own a building with ground-floor commercial and apartments above, this section is the one that matters most.

The CO is a building-level document held by the owner. A ground-floor tenant cannot fix it. A ground-floor tenant can absolutely break it.

Administrative Code §28-118.3.1 requires a new CO where a building is altered so as to change "from one occupancy group to another, or from one zoning use group to another, either in whole or in part." That phrase — in part — is what puts a single storefront in a position to pull the entire building's CO open.

Whether a specific conversion actually crosses a use-group line is fact-specific and needs to be confirmed by a registered architect or engineer against the current Zoning Resolution. It is worth noting that the June 2024 renumbering consolidated some categories — Use Group VI now covers both retail and service uses — so certain changes that once crossed a line no longer do. This cuts both ways, and it is not a question to answer from memory.

The Place of Assembly ceiling

Here is the mechanism that catches mixed-use owners, and it is worth understanding before you sign a commercial tenant rather than after.

DOB requires a Place of Assembly Certificate of Operation wherever 75 or more people gather indoors, including on roofs and roof terraces, or 200 or more gather outdoors. Spaces serving more than 300 must also file a Fire Protection Plan with DOB and FDNY. Restaurants, theaters, auditoriums, event spaces, and houses of worship all land in this territory.

The constraint is in DOB's own guidance: a Place of Assembly application "must not exceed in occupant load the existing Certificate of Occupancy," and "when the number of occupants is being changed for a proposed assembly space, a separate application to amend the number of occupants on the Certificate of Occupancy must also be filed."

To make that concrete — as an illustration, not a specific case — say a tenant signs for a restaurant on your ground floor and needs 90 seats. Your building's CO shows a design occupant load of 60 for that floor. That tenant cannot obtain their Place of Assembly certificate. The fix is an amendment to your CO, and under §28-118.4.1 the application must be made by or on behalf of the owner. The tenant cannot open until you file. Their construction schedule, their opening date, and their ability to start paying rent all now sit on your desk.

Worth adding: §28-118.12 makes clear that a CO does not by itself authorize place-of-assembly use. The CO and the Place of Assembly certificate are two separate documents, and you need both.

Three things this changes about how you lease

1. Check the CO before the LOI, not after the lease. Confirm the Use Group and the per-floor design occupant load will support the tenant's intended use and headcount.
2. Allocate the CO amendment in the lease. Who files, who pays the architect and DOB fees, what the remedy is if DOB denies the amendment. Only the owner can file it, so silence in the lease defaults the obligation to you.
3. Clear violations before you need them cleared. A CO amendment requires no open violations and no open jobs at the building — and §28-118.14 separately allows DOB to refuse a CO pending unpaid penalties. An unrelated open violation on an upper floor can hold a ground-floor build-out hostage for months.

This is a substantial part of what landlord-side representation is for on a commercial lease. The tenant's broker is not going to raise the occupant load on your CO.

When You Need a New or Amended Certificate of Occupancy

Three things trigger the requirement: a change in use, a change in egress, or a change in occupancy.

Whether you need a brand-new CO or an amendment to the existing one has a statutory line. Under §28-118.16, where a building exceeds three stories in height and the change does not exceed 20 percent of the total floor area, an amendment to the existing certificate issues. Larger changes require a new CO. For minor alterations that do not require either, DOB may issue a Letter of Completion instead.

Getting there requires final sign-offs on construction, plumbing, elevator, and electrical work; a final survey; no open applications; no open violations; an owner's cost affidavit; and an approved Schedule of Occupancy. It also requires a signed statement of compliance from the registered design professional of record under §28-118.4.2 — which is why an architect or engineer is not optional on this. The "no open violations" condition is the one that catches owners out: violations entirely unrelated to the current work still have to be cleared before the certificate issues. That makes routine compliance hygiene — including staying on top of HPD violations on the housing-maintenance side — a prerequisite for work you may not have scheduled yet.

Costs vary too widely by scope to quote a useful range. The drivers are architect or engineer fees, DOB filing fees, the inspections and sign-offs your particular work requires, and — frequently the largest and least predictable line — clearing whatever violations are already open against the building.

What to Check Before You Sign

Nearly every consequence in this guide — the rent bar, the penalties, the vacate exposure, the stalled tenant build-out — traces back to a gap between what the CO says and what is actually happening in the building. And that gap is almost always discovered late: by a lender during a refinance, by a buyer's attorney in diligence, or by a tenant's lawyer in housing court.

It is inexpensive to catch at the front end. It is expensive everywhere else.

The pre-lease checklist is short:

• Legal unit count on the CO versus the unit you are about to lease
• Use Group versus the tenant's intended use
• Design occupant load versus the headcount that use requires
• TCO status and expiration date, if the building is not on a final CO
• Open violations that would block a future amendment if you need one

Any owner can pull their own CO in ten minutes. What takes experience is reading a decades-old document against a current rent roll and a prospective tenant's business plan, and knowing which mismatches are cosmetic and which ones put the rent roll at risk.

At Meraki, this is built into how we take work on. When we onboard a building for property management, we pull the CO and the building's violation data as part of onboarding, so we know what we are managing and where the compliance gaps are before they surface on someone else's timeline. When we are representing an owner on a specific commercial lease, or taking a unit to market on the residential side, we check the CO before the listing agreement is signed. Discovering an occupant load or use group problem after a space is already on the market means the deal was mispriced from the start.

Frequently Asked Questions

The Takeaway

Your CO is not a closing document. It is the operating license for your rent roll — it defines how many units you may legally rent, what each floor may be used for, and how many people may occupy it. When the building drifts away from what the document says, the fines are a rounding error next to the rent exposure.

If you do one thing after reading this: pull your CO, check the dwelling-unit count and the Use Group against what you are actually renting today, and confirm whether you are operating on a final certificate or a temporary one. Most owners find everything in order. The ones who do not would much rather learn it now than from a lender, a buyer, or a tenant's attorney.