What is a Certificate Of Occupancy

by | Last updated Feb 6, 2021 | General Architecture, NYC DOB

A Certificate of Occupancy is a document that describes the legal use and maximum occupancy for a building. The Certificate lists individual building uses, number of people who can occupy each space, a description of each use, and various other building details.

Below is an example of a two page Certificate of Occupancy for a two family home in New York.

Certificate of Occupancy Building Information

Certificate of Occupancy Building Information Page


Certificate of Occupancy Use Description

Certificate of Occupancy Use Description


What is a Certificate Of Occupancy 

The Department of Buildings issues a certificate Of Occupancy (also known as a “CO”, or “C of O”) to identify the legal use of a building. The DOB will issue the Certificates Of Occupancy at the completion of a New Building (or house) or Alteration to a building (or Home) requiring a new Certificate of Occupancy. They issue the Certificate after completion of construction, all required inspections, and completion of all paperwork. Obtaining a Certificate Of Occupancy requires coordination and thorough review of the building. There is a great deal of bureaucracy to building (or home) development and occupancy.


What Information is on a Certificate Of Occupancy?

  • General Building Information
  • Certificate Type
  • Applicable Building Code
  • Building Construction Classification
  •  Building Occupancy Group
  • Multiple Dwelling Law Designation (if applicable)
  • Building Size
  • Description of Fire Protection Systems
  • Type and number of open spaces
  • Additional Limitations / Restrictions
  • List Of Floors with:
    • Maximum number of persons per space
    • Structural live load per floor
    • Building Code Occupancy Group
    • Number of Dwelling or Rooming Units
    • Zoning Use Group per space
    • Description of Each Use


Video Explaining A Certificate of Occupancy



How to Read a Certificate Of Occupancy

The following explanation is based on a typical New York City Certificate of Occupancy. The details may differ in different cities or counties. Additionally older Certificates may vary as well.


Certificate Of Occupancy Number and Statement

At the top of a CO you will see in large letters “Certificate of Occupancy“.

On the Certificate of Occupancy you will see a “CO number” this is the number of the specific property’s Certificate. If this ends with an F it is a final Certificate of Occupancy, we will get back to this distinction later in this blog post.

The Page Count is located at the top right hand corner. A CO for a single family house may be only 2 pages but a large building could easily be 5 to 10 pages.

There is a paragraph at the top explaining what a Certificate of Occupancy means.

“This certifies that the premises described herein conforms substantially to the approved plans and specifications and to the requirements of all applicable laws, rules, and regulations for the uses and occupies specified. No change of use or occupancy shall be made unless a new certificate of occupancy is issued. This document or a copy shall be available at the building for inspection at all reasonable times”

General Building Information

The Certificate of Occupancy always starts with general building information.

Borough & Address

The first piece of information on a CO in NYC is the Borough: Manhattan, Bronx, Brooklyn, Queens, or Staten Island.

Below the borough is the property address.

Building Information Number

Every building in NYC has a Building Information Number or BIN. These are specific numbers to identify the building in the Department of Buildings System. If you are doing records research on a property you may want to check if it has an old obsolete BIN for historic records. Empty lots do not normally have BIN numbers. The Department of Buildings (DOB) issues the Building Information Number (BIN). All this information is available on the NYC DOB BIS or Building Information System.

Block and Lot

The Certificate of Occupancy will list the Block and Lot. Every block has a Block Number and every lot within a block has a Lot Number. The Department of Finance (DOF) issues these numbers.

Building Type

The Building type will be New or Altered. In New York City you will file a new building or new home as an NB Application. you will file Alterations to an existing building (if it must receive a new or amended Certificate of Occupancy) as an Alteration Type 1 (Alt 1).

Type of Certificate of Occupancy

A Certificate of Occupancy can be a Temporary or Final Certificate. If there is a minor pending issue holding up the Final Certificate but the building is otherwise ready to be occupied you can apply for a temporary Certificate of Occupancy. You must renew the Temporary Certificate regularly or replace it with a Final Certificate of Occupancy.

Effective Date 

The Certificate of Occupancy Effective Date of issue for the CO. If you have a Temporary Certificate of Occupancy there will also be an expiration date. In NYC this is typically 3 months from the Effective Date.

Building Code

There is normally a statement saying “This building is subject to this building code:”followed by the applicable code. This will indicate the date the application was filed and what code it was reviewed on. If it is an alteration to an existing building it may possible qualify under older building codes dependent on the case. I have seen Certificates of Occupancy with this section left blank. You can do records research on the DOB BIS if you want to figure this out when it is missing.

Metes and Bounds

The Metes and Bounds are the outline of the property. This detail is not on Certificate of Occupancy. You can find this in the DOB records on the PD1 form submitted by the Architect of Record. The CO states “For Metes and Bounds please see BISWeb” this is the DOB Building Information System. You can fine the Application forms in the Virtual Job Folder.

Building Classifications

Construction Classification

The Construction Classification is the type of construction a building is made of. The current codes identify Construction Classification I – V. These designations are different for buildings built under older codes.

Building Occupancy Group 

The Building Code identifies all types of building uses into occupancy groups. This is different from a Zoning Use Group. The Building Occupancy Group will determine what codes apply to the building.

Multiple Dwelling Law

If the building is a Multi-family residential building in NY it will have a Multiple Dwelling Law classification. Otherwise this will not be applicable.

Number of Stories

The Number of Stories within the building is listed on a Certificate of Occupancy this does not count a cellar, mezzanines, or roof.

Building Height

The building height is on the CO document.

Number of Dwelling Units

If the building is a residential building the number of dwelling units will be listed.

Fire Protection Equipment

The Certificate of Occupancy will list all the fire protection equipment in the building if there is any. This includes fire alarms, sprinklers, standpipe etc…

Open Spaces

The type and number of any open spaces on the property will be identified on the document as well. These can be outdoor parking spaces, plazas, outdoor eating etc…


“The Certificate is issued with the following legal limitations”

There is an area for legal limitations and restrictions. These can be many things such as a Restrictive Declaration. This will vary from project to project.

Outstanding Requirements

If the Certificate issued is a temporary this section will be filled in listing the number of outstanding items. If a Final Certificate of Occupancy was issued this section should be blank.

Borough Comments

In NYC each of the five boroughs have their own Department of Buildings Borough Office. These offices issue the Certificates of Occupancy. There may be comments to the document but this section is often blank.

 Permissible Use and Occupancy

The Use and Occupancy section is based on the Schedule A supplied by the Architect of Record on the project. This is a list of all the floors with their legal use and occupancy. This section is a chart showing the following information.

Floors From To

In cases where consecutive floors are the same it will be a floor range.

Maximum Persons Permitted

If there is a limitation to the number of people per floor or per space this will be listed. For example a theater or restaurant would list the maximum number of people allowed.

Live Load

Live load is a structural engineering term for the amount of weight the engineer must use to determine what the floors must support. This is not counting building materials and structure. This is the weight of people and typical furniture and non structural elements. A library may have a high live load to support all the books as well as the shelves and people.

Building Code Occupancy Group

If you have a mixed use building all the spaces will be identified with separate occupies. These are the building code Occupancy Groups that determine what codes apply. This is different from the Zoning Use Group.

Dwelling or Rooming Units

Welling units are an apartment or family, rooming units are hotel rooms or dorms. The number of units per floor will be listed on the Certificate of Occupancy if applicable. There was a period of time when the COs in NYC listed the number of rooms in the apartments but this is no longer done for new COs. you may may can encounter older Certificates with this information still listed.

Zoning Use Group

The Zoning Use Group will be listed for each space or floor within a building. This is not to be confused with the Building Code Occupancy Group. Zoning codes and building codes are two completely different things.

Description of Use

Each floor or space will have a brief description. These should be concise and to the point yet clear. I have seen some terribly written Certificates of Occupancy so we always try to make sure this is written in a clear manner. The architect writes this and the DOB approves it. The wording does not come from DOB.

Additional Information

At the end there is a section for additional information. this could be anything from Easements to special notes.

DOB Signatures

The bottom of the Certificate will be signed by the Commissioners of the Department of Buildings.


Requirements for a NYC Certificate of Occupancy 

Below is a list of some of the items that may be required to obtain a Certificate Of Occupancy.

  • Final Construction inspection Sign-off
  • Final Plumbing inspection Sign-off
  • Elevator Sign-off
  • Electrical Inspection Sign-off
  • Special Inspections Sign Off
  • Progress Inspections Sign Off
  • EN2 As Built Energy Analysis
  • Final Building survey
  • Final Builders pavement plan
  • Property Address from Borough President’s Office
  • No open applications
  • No open violations
  • Owner’s Cost Affidavit (PW3)

Additionally you will file a PW7 in order to request a certificate of occupancy upon completion of all required items.

Alteration Type 1 and New Buildings

The DOB will issue a Certificate Of Occupancy for 1 of 2 project types: New Buildings or Alteration Type 1.

New Building

All new buildings must obtain a C of O in order to be occupied. This involves filling a NB New Building application with the NYC Department of Buildings.

Alteration Type 1

An Alteration Type 1 or Alt 1 is filed for any alteration that requires a New Certificate Of Occupancy. This is any alteration where there is a change in Use, Occupancy, or Egress.


Letter Of No Objection

Sometimes when you have an existing building you do not know if an alteration will require a new certificate of Occupancy or not. Or if a proposed use qualifies under the existing use. Sometime your building does not have a Certificate Of Occupancy.

Letter Of No Objection or LNO

If you own a building which does not have a Certificate Of Occupancy you can file a Letter Of No Objection or LNO with the NYC DOB to determine if the proposed use requires a new Certificate Of Occupancy. An LNO is not a permit. It is literally just stating that the DOB does not object to the proposed use. You will file construction work separately for permits.

Letter Of Verification or LOV

If you own a building which has a Certificate Of Occupancy but you are uncertain if a specific use is covered you can file a Letter Of No Verification or LOV with the NYC DOB to determine if the proposed use requires a new Certificate Of Occupancy. An LOV is not a permit. It is literally just stating that the DOB verifies the proposed use is covered under the existing CO. You will file construction work separately for permits.


Temporary Certificate Of Occupancy

Upon request the DOB will issue a Temporary Certificate Of Occupancy or TCO before a final Certificate Of Occupancy. This is usually done when there are some open items on the building that are not critical for the C of O. Below is a list of some of the items that may be required to obtain a Temporary Certificate Of Occupancy.

  • Temporary or Final Construction inspection sign-off
  • Temporary or Final Plumbing inspection sign-off
  • Temp or Final Electrical inspection sign-off
  • Temp Elevator sign-off (if applicable)
  • TCO Fees


NYC Certificates Of Occupancy

As an architect I study NYC building protocols, but these are complicated and quite involved issues. In this article we reviewed some of the basic concepts with regards to a Certificate Of Occupancy. This post does not assume to cover every possible issue or condition, but provide a general overview of the topic.


Thank you for reading our blog post on What is a Certificate Of Occupancy.

I hope this was helpful. If you would like to speak with an architect about a potential project you can contact us at Fontan Architecture directly.


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Jorge Fontan
Jorge Fontan

This post was written by Jorge Fontan AIA a Registered Architect and owner of New York City architecture firm Fontan Architecture. Jorge Fontan has earned 3 degrees in the study of architecture including two degrees from the City University of New York and a Masters Degree in Advanced Architectural Design from Columbia University. Jorge has a background in construction and has been practicing architecture for 20 years where he has designed renovations and new developments of various building types.