Brunswick, Maine
Brunswick, ME Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 5/10
Last Updated: 9/23/2025
Image source: Town of Brunswick
What You Need to Know
No Development Review is required, but a safe water supply and appropriate waste management verification is needed prior to issuing a building permit.
Type of Permit Required
ADUs in Brunswick require a building permit.
ADU Rules
An accessory dwelling unit does not require Development Review.
The creation of an accessory dwelling unit shall not be counted for density purposes.
ADUs are allowed on lots used for single-family or two-family homes, either within the main house or in a detached structure.
Only one ADU is allowed per lot; any additional dwelling units must meet full density and dimensional requirements.
When possible, the ADU entrance should be located on a different side of the house than the main dwelling entrance.
An ADU may not exceed 1,100 square feet or 75 percent of the size of the primary dwelling, whichever is smaller. Floor area from a garage or carport that is part of the ADU does not count toward this limit.
A detached ADU may not be taller than the primary home, unless it is built above a garage and meets all dimensional requirements.
A detached ADU may not be taller than the primary home, unless it is built above a garage and meets all dimensional requirements.
The ADU must remain under the common ownership and cannot be sold separately as a condominium unit.
No permit for an accessory dwelling unit may be issued until the applicant has provided written verification from qualified professionals that the accessory dwelling
(a) will have adequate and safe water supply;
(b) will have adequate connection to wastewater services, as required by 30-A.M.R.S. §4364-B(7), as amended.
Resources:
https://www.brunswickme.gov/AgendaCenter/ViewFile/Item/2715?fileID=32584
Brunswick, Maine
Brunswick, Maine Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 8/10
last updated 4/13/2020
What you need to know about Brunswick
Brunswick allows detached and attached accessory dwelling units by right in all residential districts! Like other towns across New England they refer to backyard homes as detached accessory apartments. Overall, Brunswick’s bylaw is very housing development friendly which means landowners have lots of flexibility with what they can do with their land creating. This means property owners have ample opportunity to create multiple backyard homes (tiny homes) for resale or to rent out.
However, Brunswick has over 30 different zoning districts, each with different rules about what and where you can build. ADUs bypass the density requirements (dwelling units per acre), but must abide by all other dimension rules such as building heights and setbacks.
Type of Permit Required:
Brunswick allows both attached and detached ADUs by right without a “development review”
Other Rules in Brunswick:
Backyard Homes (ADUs) can be built on single-family, two-family or commercial properties
Only one ADU is allowed is allowed per lot. (multiple backyard homes can be built in accordance with density rules)
The front of any building cannot be modified to build the ADU
The ADU cannot have more living area than 35% of the current home or 750SF, whichever is greater
The ADU must be secondary, incidental and subordinate to the properties primary use
See the full text here: Zoning Ordinance, Section: 3.4.2. (A) Accessory Apartments