Accessory Structures in Somerville, MA (2026)
5 verified accessory structures rules for Somerville, Massachusetts, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Somerville was an early Massachusetts adopter of ADU zoning and now complies with the 2024 Affordable Homes Act mandating ADUs by right in all single-family zones statewide.
Somerville ADU Rules
Few RestrictionsM.G.L. c. 40A, Section 3
No zoning ordinance or by-law shall prohibit, unreasonably restrict or require a special permit or other discretionary zoning approval for the use of land or structures for a single accessory dwelling unit, or the rental thereof, in a single-family residential zoning district; provided, that the use of land or structures for such accessory dwelling unit under this paragraph may be subject to re...
Shed Rules
Sheds under 200 square feet typically do not need a building permit in Somerville but must meet zoning setbacks. Larger sheds require a building permit from Inspectional Services.
Somerville Shed Rules
Some RestrictionsGarage Conversions
Converting a garage to living space in Somerville requires a building permit and may qualify as an ADU under the 2024 Affordable Homes Act with relaxed zoning review.
Somerville Garage Conversions
Some RestrictionsM.G.L. c. 40A, Section 3A
Section 3A. (a)(1) An MBTA community shall have a zoning ordinance or by-law that provides for at least 1 district of reasonable size in which multi-family housing is permitted as of right; provided, however, that such multi-family housing shall be without age restrictions and shall be suitable for families with children. For the purposes of this section, a district of reasonable size shall: (i...
Carport Rules
Carports are treated as accessory structures in Somerville and require building permits and zoning setback compliance. Many lots cannot accommodate a carport due to dimensional limits.
Somerville Carport Rules
Some RestrictionsTiny Homes
Tiny homes on foundations can qualify as ADUs in Somerville under the 2024 Affordable Homes Act. Tiny homes on wheels are treated as RVs and generally cannot be used as permanent dwellings.
Somerville Tiny Home Rules
Heavy RestrictionsLooking for Middlesex County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Somerville city rules.
Accessory Structures in Middlesex County →