ADU Rules in Boston, MA
Boston operates under its own zoning charter with ADU-specific rules.
HIGH Confidence Data
Zoning Districts
1F — Single-Family Residential
Single-family detached residential district
Default Zone
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 800 sq ft | 15 ft | None | Yes |
| Attached ADU | By Right | 800 sq ft | 25 ft | None | Yes |
| Interior Conversion | By Right | 900 sq ft | — | None | Yes |
2F — Two-Family Residential
Two-family residential district
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Detached ADU | By Right | 800 sq ft | 15 ft | None | Yes |
| Interior Conversion | By Right | 900 sq ft | — | None | Yes |
3F — Three-Family Residential
Three-family residential district
| Type | Approval | Max Size | Height | Parking | Owner Occ. |
|---|---|---|---|---|---|
| Interior Conversion | Special Permit | 900 sq ft | — | None | Yes |
Transit Stations
Properties near transit stations may qualify for parking exemptions.
Airport
SUBWAY
Andrew
SUBWAY
Aquarium
SUBWAY
Ashmont
SUBWAY
Back Bay
SUBWAY
Back Bay (CR)
COMMUTER RAIL
Beachmont
SUBWAY
Broadway
SUBWAY
Chinatown
SUBWAY
Copley
SUBWAY
Downtown Crossing
SUBWAY
Fields Corner
SUBWAY
Forest Hills
SUBWAY
Green Street
SUBWAY
Haymarket
SUBWAY
Hynes Convention Center
SUBWAY
JFK/UMass
SUBWAY
Jackson Square
SUBWAY
Kenmore
SUBWAY
Massachusetts Ave
SUBWAY
Maverick
SUBWAY
North Station
SUBWAY
North Station (CR)
COMMUTER RAIL
Park Street
SUBWAY
Roxbury Crossing
SUBWAY
Ruggles
SUBWAY
Ruggles (CR)
COMMUTER RAIL
Savin Hill
SUBWAY
Shawmut
SUBWAY
South Station
SUBWAY
South Station (CR)
COMMUTER RAIL
State Street
SUBWAY
Stony Brook
SUBWAY
Suffolk Downs
SUBWAY