Certificate of Occupancy NYC: How to Look It Up and Fix a Mismatch

If you are buying or selling a house in Queens, the certificate of occupancy NYC rules decide one question that comes up in almost every sale: is this house legally what the listing says it is? A house sold as a two-family, a basement described as a rental, an attic used as a bedroom floor: each of those is either backed by the city’s records or it is not. The document that answers the question is the certificate of occupancy, usually shortened to CO or C of O.

I have worked with buyers and sellers in Queens, Brooklyn and Long Island for 15+ years, in English and Polish. The CO is one of the first records I pull when a house comes to market, because a mismatch between the house and its paperwork is far easier to handle before an offer than after a lender finds it. This guide explains what a CO says, how to find one, what happens with older houses that never had one, what to do when the use and the CO do not match, and what changes for buyers, sellers, co-ops and condos.

What is a certificate of occupancy in NYC?

A certificate of occupancy is issued by the New York City Department of Buildings (DOB). According to the DOB’s certificate of occupancy page, it states a building’s legal use and/or type of permitted occupancy. In plain terms, it tells you how the city has approved the building to be used: how many dwelling units, which floors are residential, whether a ground floor is a store, and how many people a space is meant to hold.

The same page explains that a CO also confirms several things about the work that created the building or changed it: that the completed work complies with the applicable laws, that the paperwork is complete, that fees owed to the Department are paid, that relevant violations are resolved and that other city agencies have given their approvals.

When the city requires one

The DOB lists the situations clearly:

• New buildings must have a CO.
• Existing buildings need a current or amended CO when there is a change in use, egress or type of occupancy.
• No one may legally occupy a building until the Department issues a CO or a Temporary Certificate of Occupancy.

“Egress” means the ways out of the building or a unit: stairs, doors, exits. “Occupancy” is the type of use the building code assigns, such as residential. When any of those change, the CO is supposed to change with them.

A CO does not expire

The DOB states that a certificate of occupancy has no expiration date. A CO issued decades ago is still the controlling document unless a later one replaced it. That is why an old CO can matter so much in a modern sale: if the house was converted after that CO was issued and nobody filed for a new one, the paperwork still describes the house as it used to be.

Why it matters more in Queens

Queens has a large stock of one-family and two-family houses, many of them built in the first half of the twentieth century and changed over the years: finished basements, attic rooms, rear extensions, enclosed porches, second kitchens. Every one of those changes can affect whether the house still matches its CO. If you are looking at a two-family specifically, our guide to buying a multi-family home in Queens covers the rest of the due diligence around rental units.

How to read a certificate of occupancy

A CO looks technical, but most buyers and sellers only need a few lines from it. Older COs are typed forms; newer ones issued through DOB NOW show CO details and floor use records on screen. The information you are looking for is the same.

Cellar and basement are not the same word

On a CO and in the building code, a cellar and a basement are different spaces, and the difference affects what the space can legally be used for. The general idea is that a basement sits partly above the street grade and a cellar sits mostly below it. Many Queens houses list a cellar on the CO for storage or a boiler room. If that cellar now holds a bedroom or an apartment, the house does not match the document, and that conversation belongs with an architect or engineer and your attorney.

The CO is not the tax class

A common mix-up: the Department of Finance assigns each property a building class for tax purposes, and a house can be classed on the tax side as a two-family dwelling. That tax label is not the legal use. The DOB’s CO, or for an older house the DOB’s records of its historical use, is what establishes how many families the building may hold. When the tax class, the listing and the CO disagree, the CO is the one lenders and attorneys look at. Our guide to property taxes in Queens NY explains the tax side of the same property records.

Certificate of occupancy NYC lookup: how to find a CO in BIS and DOB NOW

You do not need a lawyer or an expediter to look up a certificate of occupancy. The records are public and free to view online. The DOB keeps them in two systems, and which one you use depends on when the CO was requested.

COs requested before March 1, 2021: BIS

1. Go to the Buildings Information System (BIS) at nyc.gov/bis.
2. Search by address using the Building Information Search.
3. On the Property Profile page, select “View Certificates of Occupancy.”
4. If a CO was issued, it appears in the list; open the linked PDF to read or print it.

COs requested on or after March 1, 2021: DOB NOW

1. Go to the DOB NOW public portal at nyc.gov/dobnow.
2. Search by property address.
3. At the top of the Property Profile page, select “Certificate of Occupancy.”
4. A window opens with the CO details and the floor use records, with a Print button.

Search both, and read every CO listed

A building can have more than one CO over its life: one for the original construction and another after an alteration. Look at the full list, check the dates, and read the most recent one carefully. For houses that had work done around 2021, it is worth checking both systems, because the history may be split between them.

What it means when nothing comes up

An empty result does not automatically mean the house is illegal. There are three common explanations:

• The house was built before 1938, when no CO was required, and nothing since then triggered one (see the next section).
• The CO exists on paper but was never scanned or linked to the address you typed; try variations of the address and the block and lot.
• The house was built or changed in a way that should have produced a CO, and no one ever completed that process.

Only the third one is a real problem, and telling them apart takes a closer look at the permit history in the same systems. If you cannot tell which case you are in, the DOB says you can call 311 and ask for Certificate of Occupancy.

Look at the permits and violations while you are there

The same property profile shows job filings, permits, complaints and violations. Open jobs and open violations matter because, under the DOB’s rules, a property cannot obtain a CO while it has open applications or violations. A buyer’s attorney and inspector will look at this history too; our home inspection in NYC guide explains how the inspection and the records review fit together.

Houses built before 1938 and the Letter of No Objection NYC

Many Queens houses were built before 1938. That year matters because, as the DOB states, buildings built before 1938 are not required to have a CO unless later alterations changed their use, egress or occupancy. So a 1920s two-family in Woodhaven or Richmond Hill may have no CO at all and still be perfectly legal, as long as its use has not changed since it was built.

What a Letter of No Objection is

For those older buildings, the DOB can issue a Letter of No Objection (LNO) to confirm the building’s legal use. According to the NYC 311 page on Letters of No Objection, the DOB provides these letters to confirm the legal use of a building constructed before 1938. The DOB’s guidance adds that a letter is issued if the proposed or actual use complies with the city’s building code and zoning, and the building’s occupancy load and exits are unchanged.

How to request one

The 311 guidance describes the process as an in-person request at the DOB borough office where the property is located, during walk-in hours on weekdays in the morning. For Queens, that office is at 120-55 Queens Boulevard in Kew Gardens. The DOB’s own page says to use the LNO form when you request it. Before the visit, research the property’s construction records in BIS or DOB NOW.

What to bring

The point of the request is to show how the building has been used for a long time. The 311 guidance lists the kinds of materials that help:

• Old property surveys
• Property deeds
• Water bills
• Tax assessments
• Photographs

If you are a seller who inherited an older house, these papers are often in a box somewhere in the house or with the family’s attorney. Our guide to selling an inherited house in New York covers the rest of the estate paperwork that goes alongside them.

What an LNO does not do

An LNO confirms an existing, longstanding legal use. It does not approve a conversion. If the house was built as a one-family and later turned into a two-family, a letter confirming the original use will not help the seller, and the change would need its own filing and approval. The official pages do not list a fee or a processing time for the letter, so ask the borough office or your expediter for current details before you plan a closing date around it.

Temporary CO, final CO and Letter of Completion

Buyers of newer construction and recently renovated houses will see a few other documents. Each one means something different.

Final certificate of occupancy

The DOB issues a final CO when the completed work matches the submitted plans for a new building or a major alteration. This is the document you want to see on a newly built house or a fully converted building.

Temporary certificate of occupancy (TCO)

According to the DOB, a TCO is issued when a property is found safe to occupy but there are outstanding issues that must be resolved before a final CO can be issued. The DOB states that TCOs typically expire 90 days after issuance and may be renewed if the outstanding issues are not resolved in time, and that the fee for a TCO is $130 unless an exemption applies. The DOB also notes that a new TCO is required if the space has been unoccupied for more than 30 days before it is reoccupied.

For a buyer, a TCO is a signal to ask questions. What is still open? Who is responsible for getting the final CO, and by when? Is the TCO current today, or did it lapse? Those answers belong in your attorney’s review and, when needed, in the contract.

Letter of Completion

The DOB can issue a Letter of Completion for minor alterations that do not require a new or amended CO. A new kitchen or bathroom that does not change the number of units or the exits is the type of job that may close out with a letter instead of a new CO. When a seller tells you the renovation was “all done with permits,” a Letter of Completion or signed-off permits are what that sentence should mean.

When the house and the CO do not match: common Queens cases

The real question in most sales is not whether a CO exists. It is whether the house as it stands today matches it. These are the situations that come up most often with Queens houses, and the usual direction each one takes. The right fix for a specific house is a question for a registered architect or professional engineer and your attorney.

Why “legal two-family” is a phrase to verify

Listings sometimes say “legal two-family.” The phrase is only as good as the records behind it. Before relying on it, look up the CO or, for an older house, the historical records and any LNO. If the house really is a legal two-family, the documents will show it. If it is a one-family with a second unit, the price, the mortgage and the rent you planned around may all change.

The city’s enforcement side

Occupying a building for more families than its legal approval allows can lead to DOB violations and penalties against the owner. A new owner inherits the building as it is, including its records. That is the core reason a buyer looks at the CO before signing a contract, not after.

Why the CO matters to buyers: lender, appraisal, insurance and rent

For a buyer, the certificate of occupancy affects three things at once: the mortgage, the value and any rental income. None of these is a reason to panic over a mismatch. Each is a reason to know about it early.

The lender and the appraisal

When you finance a purchase, the lender’s appraiser describes the property, including the number of units. Lenders commonly compare that description with the legal use. If the appraiser sees two kitchens and two units in a house the records show as a one-family, the lender may ask for proof of legal use, ask for changes before closing or decline to lend on the property as a two-family. The exact rules depend on the loan program and the lender, so ask your loan officer early how they handle a mismatch.

The value

A house that is legally a one-family is usually valued as a one-family, even if it is used as two. If your budget assumes rent from a second unit, that assumption only holds if the unit is legal. Our down payment for a house in NYC guide explains how the loan amount and the property type work together.

Rental income and tenants

A buyer who plans to rent a unit needs that unit to be legal. If there are tenants already living in a space the CO does not cover, that is a question for your attorney before contract, because restoring the space to its legal use can mean the tenants have to leave.

Title and the attorney’s review

Your attorney’s title and municipal searches usually include the building department records. Our guide to hiring a real estate attorney in NYC explains how that review fits into the contract period, and our title insurance in NYC guide covers what the title company does and does not insure.

Buying a house without a certificate of occupancy in NYC

Buying a house without a certificate of occupancy in NYC is common and often fine, as long as you know which of the three cases you are in. A pre-1938 house with a consistent use history is a different purchase from a newer house that was converted without permits.

Before you make an offer

1. Look up the CO in BIS and DOB NOW, and print what you find.
2. Note the year the house was built, from the listing and the city’s records.
3. Count the units, kitchens and separate entrances during the showing.
4. Compare the three: what the house is, what the listing says and what the records say.
5. Ask the listing agent directly what documents the seller has: a CO, an LNO, old surveys, permit sign-offs.

During the contract period

Your attorney can ask the seller’s side for documents, raise the issue in negotiation and, where the parties agree, write protections into the contract. Depending on the house, that may mean a requirement that the seller deliver proof of legal use before closing, a price that reflects the house’s legal status, or a decision by the buyer to accept the house as it is legally described. Which route fits is a legal question for your attorney; the timing question is one I help with, because a document the seller has to request from the city can move a closing date. Our guide to how long it takes to close on a house in NYC shows where those delays usually land.

The Property Condition Disclosure Statement

Sellers of one- to four-family houses in New York generally complete the Property Condition Disclosure Statement under Real Property Law Section 462. One of its questions asks whether there are certificates of occupancy related to the property, with “yes,” “no,” “unknown” and “not applicable” answers, and asks for an explanation if the answer is no. Read that answer next to the records you looked up yourself.

What sellers should do about the CO before listing

For sellers, the CO is a preparation task. Every week you spend on it before the listing goes live is a week you do not spend under contract with a nervous buyer and a lender asking questions.

Step 1: Pull your own records

Look up the CO, the permit history and any open violations in BIS and DOB NOW. Print the CO, or confirm there is none and note the year the house was built.

Step 2: Compare the house with the paper

Walk the house floor by floor with the CO in hand. Count units, kitchens and entrances. Look at the basement, the attic and any extension. Write down every difference.

Step 3: Gather the historical documents

For a pre-1938 house with no CO, collect old surveys, deeds, water bills, tax records and photos that show how the house has been used. If you will need a Letter of No Objection, those are the documents the borough office asks for.

Step 4: Close what can be closed

Open permits from past work and open violations are usually worth resolving before you list. A registered architect, professional engineer or licensed expediter can tell you what each one needs. The DOB’s website has a search to find licensed professionals. If you decide not to fix anything, our guide to selling a house as is in New York explains that route.

Step 5: Describe the house accurately

Market the house as what it legally is. If the house is a legal one-family with a finished basement, it is described that way. Accurate descriptions protect the seller from a contract that collapses when the buyer’s lender sees the records, and they keep the listing honest.

Step 6: Tell your attorney early

Your attorney drafts the contract and answers the buyer’s attorney. Hand over the CO, the permit sign-offs and any LNO at the start so the contract reflects the house’s real status from the first draft. Our how to sell your home in Queens guide lists the rest of the documents worth having ready on listing day.

What the CO does to your price

Pricing follows the legal use. When I prepare a comparative market analysis, which is an opinion of value and not an appraisal, I compare a legal two-family with legal two-families and a one-family with one-families. Our page on what your Queens home is worth explains how that opinion of value is built.

How to get a certificate of occupancy in NYC

If the house needs a new or amended CO, the work is done by licensed professionals and filed with the DOB. Owners do not usually file on their own. Still, knowing the list of requirements helps you understand why the process takes time and what your architect or engineer is working toward.

What the DOB requires before it issues a CO

The DOB’s CO page lists these requirements:

• Final construction, plumbing, elevator and electrical inspection sign-offs
• A final building survey and a Final Builders Pavement Plan, where applicable
• No open applications or violations on the property
• The Owner’s Cost Affidavit (PW3)
• An approved Schedule of Occupancy in DOB NOW: Build

Once those are in place, a Certificate of Occupancy Request is submitted in DOB NOW: Build, reviewed by DOB technical and operations staff, and the CO is issued when all requirements are met.

Who does the work

A registered architect or professional engineer prepares and files the plans. A licensed expediter often handles the filings and the follow-up with the DOB. A licensed contractor does any construction. The DOB also runs a Project Advocate program for owners who need help understanding the process.

How long it takes and what it costs

There is no single answer. A simple sign-off of an old permit is a different job from legalizing a second unit, which can require construction, zoning review and several inspections. Ask your architect or engineer for a written scope, a fee quote and a realistic timeline before you sign a contract of sale that depends on the result.

When the answer is no

Not every conversion can be legalized. Zoning, the building code and the site itself can rule out a second unit. In that case, the realistic options are to restore the space to its legal use or to sell the house as what it legally is. Our guide to selling a vacant house in New York covers the timing when a seller needs to clear tenants or contents first.

Basement apartments: City of Yes, ADUs and Local Laws 126 and 127

Basement and cellar units are the most common mismatch in Queens houses, and the city’s rules for them changed recently. They are worth understanding before you buy or sell a house with a lower-level apartment.

What the city adopted in 2024

According to the DOB’s page on ancillary dwelling units, Local Laws 126 and 127 of 2024 were enacted in December 2024 alongside the City of Yes for Housing Opportunity zoning amendment. Local Law 126 creates a pilot program for legalizing some pre-existing basement and cellar apartments. Local Law 127 sets requirements for zoning, construction, fire safety and occupancy for ancillary dwelling units, often called ADUs.

Who the basement pilot covers

The DOB page lists the pilot’s community districts. In Queens, only Community District 2 is included, which covers Long Island City, Sunnyside and Woodside. The rest of the pilot area is in the Bronx, Brooklyn and Manhattan. The page also states that:

• The unit must have existed before April 20, 2024.
• The owner must apply before April 20, 2029.
• Units in flood risk areas are not eligible.
• When we checked the page in October 2026, it said pilot applications were not being accepted until DOB rules are promulgated.

If you own or are buying in that district, our guides to buying a home in Sunnyside and selling a two-family house in Woodside cover the local side of the market.

New ADUs

Separately from the pilot for existing units, the same rules allow some new ancillary units, such as certain basement, attic and backyard units, when they meet the code and zoning requirements. The DOB page lists limits, including that subgrade units are not permitted in high-risk flood areas. The Schedule of Occupancy now includes “Ancillary Dwelling Unit” as a description of use, which means a legal ADU appears in the CO records.

What this means in a sale today

For most Queens houses outside Community District 2, an existing basement apartment that is not on the CO is still not legal just because the city has a program. For a buyer, the existence of the program is not a reason to pay for a basement unit as if it were already legal. For a seller, it is not something to promise in a listing. Check the DOB page for the current status before relying on any of it.

Co-ops, condos and the certificate of occupancy

If you are buying an apartment rather than a house, the CO question looks different. The CO covers the whole building, not your single unit, and the building’s board, managing agent and sponsor deal with it.

Co-ops

A co-op buyer purchases shares and a proprietary lease, not real property. The building’s CO still matters: it confirms how many apartments the building is approved for and how the ground floor and lower levels may be used. Your attorney’s review of the building usually includes questions to the managing agent about violations and open filings. Our guide to the co-op board approval process in NYC explains what else the board package and the building review cover.

Condos

In a newer condo building, the final CO or a current TCO is part of the sponsor’s documentation. A buyer in a building that is still on a TCO should ask what remains open before the final CO and whether the TCO is current. Your attorney reads that in the offering plan and its amendments.

A certificate of occupancy checklist for buyers and sellers

Use this list on any house in New York City. It takes less than an hour with the address in hand, and it can save weeks under contract.

1. Look up the address in BIS and DOB NOW and open every certificate of occupancy listed.
2. Read the most recent CO: number of units, floor-by-floor use, notes.
3. If there is no CO, note the year the house was built and look for a Letter of No Objection.
4. Open the permit history: are past jobs signed off, or still open?
5. Check complaints and violations, and whether any are still open.
6. Walk the house and compare: units, kitchens, entrances, basement, attic, extensions.
7. Compare the listing description with the records.
8. Read the seller’s answer on the Property Condition Disclosure Statement about certificates of occupancy.
9. Ask the lender how it handles a difference between the appraisal and the legal use.
10. Give everything you found to your attorney before the contract is signed.

Buyers going through this for the first time can read our NYC home buying process guide for where this check sits in the full timeline, and our Queens closing costs guide for what the attorney, title and city charges add up to.

This article is for general informational purposes only. It is not legal, architectural, engineering or financial advice, and a real estate licensee cannot give legal advice; consult a licensed New York attorney and a registered architect or professional engineer about your own property. Rules, forms and procedures can change; confirm current requirements with the New York City Department of Buildings and NYC 311. Sources cited reflect those agencies’ published pages as of October 2026. Real estate brokerage services are offered by Agatha Lubas, Licensed Associate Real Estate Broker, NY License #10301213345, Keller Williams Realty Liberty, 96-10 101st Avenue, Ozone Park, NY 11416. The NYS Disclosure Form for Buyer and Seller, the NYS Housing and Anti-Discrimination Disclosure / Fair Housing Notice, and the brokerage’s Standard Operating Procedures are available on request. Equal Housing Opportunity.

Agatha Lubas

Licensed Associate Real Estate Broker · NY License #10301213345 · Keller Williams Realty Liberty

Agatha Lubas works with buyers and sellers throughout Queens, Brooklyn, Nassau County and Suffolk County, checking public records, coordinating attorneys, lenders and building professionals, and preparing houses for an accurate listing. She serves clients in English and Polish.

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