Accessory Structures in Bristol County, MA (2026)

5 county-level rules, plus city-specific rules for 5 cities in Bristol County, Massachusetts.

Verified from official government sources

Note: These county rules apply to unincorporated areas of Bristol County. If you live within an incorporated city, that city's own rules apply — see the city list below.

ADU Rules

Under Massachusetts law (Ch. 358 of Acts of 2024, effective Feb 2025), ADUs under 900 sq ft are allowed by right on single-family lots in all Bristol County municipalities. Towns cannot prohibit ADUs or impose owner-occupancy requirements. Both attached and detached ADUs are permitted under the state framework.

Bristol County ADU (Accessory Dwelling Unit) Rules

Some Restrictions

Full ordinance details →Official source ↗

Shed Rules

Shed and accessory structure regulations in Bristol County are governed by individual municipal zoning ordinances. Most towns require building permits for structures over 200 square feet. Setback requirements vary by municipality and zoning district.

Bristol County Shed & Outbuilding Rules

Some Restrictions

Full ordinance details →Official source ↗

Garage Conversions

Garage conversions throughout Bristol County require building permits and must comply with local zoning ordinances and 780 CMR building code. Conversions to living space must meet residential standards. ADU conversions may be by right under the 2025 state law if under 900 sq ft.

Bristol County Garage Conversion Rules

Some Restrictions

Mass. Gen. Laws ch. 40A, § 3A – MBTA communities multi-family zoning

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) have a minimum gr...

Full ordinance details →Official source ↗

Carport Rules

Carports in Bristol County require a building permit under 780 CMR. Zoning treats them as accessory structures with side/rear setbacks typically 5-10 feet. Lot coverage caps apply. Fall River, New Bedford, and Taunton require snow-load-rated design.

accessory-structures/carport-rules

Some Restrictions

Full ordinance details →Official source ↗

Tiny Homes

Foundation-built tiny homes in Bristol County must meet 780 CMR and local minimum dwelling size. Tiny homes on wheels classify as RVs/manufactured homes under MGL ch. 140 §32. MBTA Communities Act (ch. 40A §3A) expanded ADU options statewide.