Rules by State
/ Massachusetts
Massachusetts MA ADU Rules
Last updated: April 2025 · Reviewed by ADU Journal editorial team
ADU Friendliness Score
70
★ Favorable
Size & Dimensions
Max ADU Size (Detached)
900 sq ft
Max ADU Size (Attached)
900 sq ft
Min ADU Size
No state minimum
JADU Max Size
Not recognized statewide
Max Height (Detached)
18 ft
Stories Allowed
2 stories
Setbacks & Lot Coverage
Rear Setback
Determined locally
Side Setback
Determined locally
Front Setback
Determined locally
Minimum Lot Size
None
Fire Sprinklers
Determined locally
Owner Occupancy & Rental Rules
Owner Occupancy Required?
No
Short-Term Rental (Airbnb)
Varies by city
Rental Income Allowed?
Yes
ADUs Per Lot
1 ADU
No owner occupancy required
Permitting Process
Review Timeline (Ministerial)
Determined locally
Permit Fees
Reduced fees
Design Review Required?
No
Preapproved Plans Available?
Some cities