As of October 7th, 2021, the Town of East Hampton made changes to their Zoning Laws that are relevant to constructing an accessory structure.
§ 255-11-20 of the Town of East Hampton Zoning Laws states
that accessory buildings, including garages, if detached from the main
building, shall be not less than five feet from the main building and/or from
any other accessory building, subject to two exceptions.
One exception is that two or more accessory buildings
(including open-air appendages such as porches and screened patios) may be
approved to be built or remain, without a minimum five-foot separation, so long
as the total aggregate square footage of the buildings is less than 600 square
feet, and none of the accessory buildings are a pool house, an art studio, or
an accessory apartment, unless all three are open air appendages.
The second exception, is that an enclosed hallway, breezeway
or other design feature that functionally separates two livable spaces in a
single-family dwelling or separates a livable space in a single-family dwelling
and a detached garage, does not apply to § 255-11-20, so long as the width of
such hallway, breezeway or design feature is equal to or greater than ½ of its
length.
An accessory building is a building which is customarily
secondary to a main building. Accessory units do not include a building which
is designed, equipped, or used for cooking, living or sleeping purposes. A
common accessory building is a garage.
So, if you plan on purchasing a house with an accessory
building like a detached garage, or even plan on building one at your Hamptons
house, you should comply with this law to avoid liability.