ADUs (Accessory Dwelling Units) – Residential Properties 

Homeowners in the Town of East Hampton are permitted to construct accessory apartments, also called accessory dwelling units, or ADUS, to provide additional affordable housing for the community, provided their properties meet Town Code requirements. These additional housing units can be within the existing residence or in an accessory structure and must be rented to an eligible tenant or family member, at affordable rents. The Office of Housing and Community Development encourages the creation of these important pieces to solving the East End housing crisis. 

The Town also permits homeowners to rent out the primary residence and live in the apartment created under this program, should this result in better living arrangements for the landlord (homeowner) and tenant. However, the home, under this scenario, will become the affordable housing unit and must meet the definition of such in section 255-1-20 of the Town Code, which requires that the rent charged not exceed the established maximums (see below for more information). 

In addition, property owners may choose to rent out both dwelling units on a property. When renting the primary residence in addition to an ADU, a Town of East Hampton Rental Registry number, which is issued by the Building Department, is required.

The guidelines and requirements for apartments at residential properties — Section 255-11-63 of the Town Code — were amended in May, 2026. The updated regulations can be read here: 2026 East Hampton Town ADU Regulations

 However, please see below for some key aspects of the program and frequently asked questions. 

 A General Overview of the Application Process 

1. A homeowner interested in building a new affordable accessory apartment, or in modifying an existing space to be used as an affordable accessory apartment, must begin by submitting a Building Permit Application and Application for an Affordable Apartment in a Single Family Residence to the Building Department and follow all instructions and provide all required supporting documentation
2. Once all necessary information has been provided to the Building Department, a Building Permit will be issued and all work must be completed in accordance with the conditions of this permit. 
3. When construction is completed, inspected, and found acceptable by the Building Department, a Temporary Certificate of Occupancy (CO) will be issued to the homeowner. 
4. Upon receipt of a temporary CO, the homeowner must apply to the Office of Housing and Community Development for an Affordable Accessory Apartment Annual Rental Permit. Please follow all instructions and provide all of the required supporting documentation. This is required even if the accessory apartment is to be used by a family member.
5. Once the Office of Housing and Community Development issues its permit, it will inform both the homeowner and the Building Department and a permanent CO can be issued, closing the process
6. Please keep in mind though that permits for Affordable Accessory Apartments must be renewed on a YEARLY basis with the Office of Housing and Community Development, or sooner if a tenant changes or the property is sold to a new homeowner (transfer of permit) 

Application Form

ADU at Residence – Annual Permit Application

Apartmentos Asequibles – Residenciales-Solicitud

Frequently Asked Questions (FAQs): 

• Who is eligible to construct and/or live in an Affordable Accessory Apartment?

Any homeowner in East Hampton Township whose property meets the Town Code standards for an ADU may construct an Affordable Accessory Apartment and become a landlord. 

Tenants do not need to meet income qualifications but they must be a resident of East Hampton, have been a resident within the last five years, or be a member of the property owner’s family. Leases must be for at least one year. 

The affordable housing unit which is the subject of the permit must the sole legal residence of the tenant. 

Homeowners/landlords may choose whomever they wish as a tenant and do not need to draw from a list or any other similar pool of prospective individuals, provided the above criteria are met. 

• What is the maximum rent that can be charged?

The maximum rent that can be charged must be in keeping with the definition of an “affordable housing unit” as the same is defined in the Town Code. This means no more than 130% of the Fair Market Rent (FMR) as established and updated on a yearly basis by the United States Department of Housing and Urban Development (HUD). The table below provides the current maximum permitted rents in the Town of East Hampton based on the number of bedrooms (note that Affordable Accessory Apartments may not exceed two bedrooms). These figures DO NOT include utilities, which can result in additional costs to a tenant.  

• How big can the apartment be?

Detached apartments (accessory buildings) must be between 300 and 600 square feet in gross floor area. 

Attached apartments (within the principal dwelling unit) must be between 300 square feet and 50% of the gross floor area of the principal dwelling unit, up to a maximum of 1,200 square feet.  

No Affordable Accessory Apartment can contain more than two (2) bedrooms.  

• Can the apartment be in a detached structure?

Yes. However, properties that already have an affordable accessory apartment, an artist studio, or a two-family/multiple-family dwelling are not eligible to have apartments in detached structures.  

• How big does my lot have to be?

15,000 square feet is the minimum lot area required. This applies to both attached (within the principal dwelling unit) and detached (in an accessory building) apartments.  

The property must also be big enough to provide two (2) off-street parking spaces 

• Are there any prohibitions about where I can put an apartment?

The Affordable Accessory Apartment must meet all applicable property line setbacks for a principal structure in the zoning district in which it is located. For detached apartments (accessory buildings) all applicable principal structure setbacks with the exception of front yard setbacks must be met. 

Affordable Accessory Apartments, whether within the existing footprint of the home, in an addition to a home, or in a separate accessory building must meet required setbacks from protected natural resources, such as wetlands.  

ADUs (Accessory Dwelling Units, or Affordable Accessory Apartments) are not permitted in the Town’s Harbor Protection Overlay District and Affordable Housing Overlay District zones.  

• How much does a permit cost?

Building Permits are based on the scale of the construction project and can vary significantly. Applicants are encouraged to contact the Building Department. Applications to the Office of Housing and Community Development are currently $50 for the initial permit or for renewal of an expired permit, and $50 for an annual renewal or a transfer of permit.  

• How long does the lease have to be for?

Leases must be for a minimum of one year. 

• What are some other restrictions or pertinent considerations that I should be aware of? 

An Affordable Accessory Apartment may not be sublet 

The lot upon which the Affordable Accessory Apartment is constructed must have a valid CO for a single-family residence 

There is a limit on the number of Affordable Accessory Apartments permits. Currently, the Town allows a maximum of 40 permits in each School District, a total of 200 throughout the Town. Permits are issued in the order in which a homeowner applies to the Building Department 

The addition of an Affordable Accessory Apartment may trigger the need to update an already on-site sanitary system, or the installation of a new system. Such activities will require the approval of the Suffolk County Department of Health Services (SCDHS). You may be eligible for a Water Quality Improvement Grant under the Town’s Septic Incentive Program. For more information on this program, please contact the Natural Resources Department  

For more information about this program, please contact the Building Department and/or the Office of Housing and Community Development.