Lot Subdivision in NYC, Dividing Lots

by | Last updated Jun 23, 2020 | New York City, NYC Zoning, Property Development

Dividing lots into two or more individual lots is called a lot subdivision or lot apportionment. In NYC this must be filed with DOF and often with DOB. Depending on the zoning there may be regulations including minimum lot width and lot area that must be adhered to in order to divide the property.


Lot Apportionment

Dividing Lots In NYC

The most important factor to consider before dividing a residential lot is to make sure you comply with the minimum lot area and minimum lot width. Every residential zoning district has minimum requirements for width and area. If you are dividing a commercial zoning lot I would adhere the residential equivalent zoning district regulations.

See another blog post for a chart on minimum lots sizes in residential districts minimum lot area and minimum lot width.

NYC Lot Subdivision DOB 

When subdividing a lot you should not create any non compliant conditions this will lead to problems later if you want to develop the property. All applicable zoning codes must be satisfied in order to perform the subdivision (SI).

If an existing building is being divided it must have a fire rated wall as per code on the property line division.


Lot Subdivision / Lot Apportionment Example

We have a project where our client is dividing a lot in an R4-1 zoning district this is a subdistrict of R4 Zoning. They currently own a property 40 x 100 with a single family house on it. R4-1 allows for 2 family homes that are semi detached, meaning they are connected in the middle. The client wanted to explore if the property could legally be divided into 2 lots each with 1 semi detached house having 2 families each. This would require the demolition of the original house.


Dividing Lots Minimum Lot Width Example

The minimum lot width for a semi detached house in R4-1 is 17 feet. So if we divide the property into 2 lots we get 20 feet for each lot and we are good on lot width. 20 feet is greater then the 17 foot minimum.

Dividing Lots Minimum Lot Area Example

The property was 40 x 100 so that is 4,000 square feet. The minimum lot area for a semi detached house in R4-1 is 1,700 square feet. If we divide the properties equally we get 2,000 square feet for each. 2,000 is over the 1,700 sq ft minimum so we are good on lot area.

Since both the lot area and lot width of this residential property will meet or exceed the minimums we can divide it and make 2 semi detached homes. In this example we are making 2 family houses. The number of families is determined by the density factor. See another post we wrote about density factor.


Filing for a Lot subdivision in NYC – SI

When dividing a lot in NYC you will need to file with DOB and DOF if you are planning a new building or if there are existing buildings on the property. You will begin the process with DOF by filing an RP602 in order to get a tentative tax lot number. The property starts with one tax lot number and you will need the tentative number to proceed with filing at DOB. Once you have a tentative lot number DOB will put it into the system and you can begin to file your new building subdivision and reapportionment. Every building must be filed separately. In the example above we must file each house as a separate application with DOB even though they are attached in the middle and part of the same development.

A lot subdivision at NYC DOB is called an SI application. You will file a separate NB application for new construction. Each building will be filed separately and reviewed separately. The DOB no longer does “Cluster Jobs” or “Lead Jobs” where the multiple buildings were reviewed on one Lead Job Folder. Now they are all reviewed separately but what we do is provide an AI1 form requesting all jobs to be assigned to the same person. If the jobs are assigned to different plan examiners at DOB I would request reassignment.

Zoning Exhibits

You will need to file zoning lot exhibits with you application. These are filed at DOF first then DOB. The zoning Exhibits are usually prepared by a title company. These are supporting documents required for approval.

Unimproved Land Subdivisions

Unimproved Land is any property that does not have a building on it. If the property is an empty lot or unimproved the process for subdivision is much easier. You will not need Zoning Exhibits or DOB filing.


Department Of Finance RP602 Requirements


At the end of the job when construction is complete you must return to DOF with the following items to make the lot permanent. The following items must be presented:

  • Final Survey by Licensed Land Surveyor (showing dimensions and square footages of each lot).
    • This must have the words “Final Survey” on the document.
  •  PW1: Plan/Work Application (This is a DOB form)
    • An approved subdivision filing PW1 and or New Building Filing PW1 see Operations Policy And Procedure
      Notice #30/92.
  • PD1 approved and stamped with house numbers
    • PD1s are filed with the DOB and Borough Presidents Office. The Borough Presidents Topographic office issues the addresses for the new lots and verifies addresses for existing lots.
  • All taxes and liens for current and past years must be up to date
  • Current Deed showing ownership
  • Fees

After you refile your RP602 with all the required items the tentative tax lot number will become permanent. After that you can get a new Certificate Of Occupancy.



We wish you the best of luck with your upcoming project. Please feel free to leave questions or comments below. If you want to discuss your project with an architect you can contact us 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.