ADU Regulations in Maine and Massachusetts
The first step is knowing the rules
If you are interested in installing a granny flat (accessory dwelling unit), your first step is to review your local rules. Each town has differing rules relating to which zones ADUs can be installed in, maximum size, or rental restrictions.
Find your cities ADU Rules:
Can’t find your city? We’ll research it.
Biddeford, Maine has excellent rules for accessory dwelling units with few restrictions.
Westbrook, Maine allows an attached ADUs on property with a maximum of 800 sq ft.
Portland Maine allows two ADUs on any residential property! A single ADU can be up to 2/3 the size of the primary dwelling unit, or the size of two ADU can be equal to the size of the primary dwelling.
After updating its ADU rules in 2021, Portland has one of the most lenient ADU rules in New England. The rules provide great opportunities to add housing for families or generate rental income in Portland's booming rental market.
Western Mass Cities That Allows Oversized Tiny Homes:
Below is the full list of cities and town we’ve evaluated.
Bold font indicates detached ADUs (backyard tiny homes) are allowed.
** indicates detached ADUs are allowed By Right in at lease one zoning district (this is a good thing)
Western Mass
Chester
Montgomery
Westwood
Worthington