ADU and Small Home Regulations in Maine
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.
Check out the Maine ADU Workbook →
Find your city’s ADU Rules:
Can’t find your city? We’ll research it.
Maine cities and towns that allow detached ADUs.
That we have evaluated so far.
Biddeford, Maine has excellent rules for accessory dwelling units with few restrictions.
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.
Below is the full list of cities and town we’ve evaluated in Maine.
Greater Portland
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.
North of Portland
Southern Maine
Biddeford, Maine has excellent rules for accessory dwelling units with few restrictions.