ADU Setback Requirements in Arlington, MA
ADU setback rules for Arlington, Massachusetts. Front, side, and rear setback distances, plus height limits and lot coverage restrictions.
ADU Regulations in Arlington
Arlington follows the Massachusetts state baseline under the Affordable Homes Act. This means all Massachusetts state-level ADU rights apply — including by-right approval, no owner occupancy requirement, and standardized size limits. Arlington may also have additional local regulations that supplement the state baseline.
Setback Requirements
In Arlington, your ADU must be set back: 25 ft from the front property line; 6 ft from side lot lines; 6 ft from the rear property line. These setbacks determine the buildable area on your lot — the larger your lot, the more room you have after accounting for required setbacks.
Height Limits
ADUs in Arlington can be up to 25 feet tall (2 stories maximum). Height is measured from the average finished grade to the highest point of the roof. Consider that taller ADUs may require greater setbacks in some jurisdictions.
Planning Your ADU Placement
When planning your ADU in Arlington, start by mapping your property boundaries and subtracting the required setbacks on each side. The remaining area is your buildable envelope. Consider the location of existing structures, utility connections, access paths, and landscaping when choosing the best spot for your ADU.
Arlington ADU Rules at a Glance
Max Size
900 sq ft
% of Home
50%
Max Height
25 ft
Max Stories
2
Front Setback
25 ft
Side Setback
6 ft
Rear Setback
6 ft
Parking
1 space(s)
Approval
BY RIGHT
Owner Occupancy
Not required
Rental Allowed
Yes
Short-Term Rental
Not allowed
Arlington Building Department
Arlington Inspectional Services Department
51e Grove St, Arlington, MA 02476, USA
Phone: (781) 316-3390
Frequently Asked Questions
What are the ADU setback requirements in Arlington, MA?
In Arlington, your ADU must be set back 25 ft from the front, 6 ft from side lot lines, 6 ft from the rear. These reflect state baseline requirements — Arlington's local setbacks may differ. Check with your building department.
Can I build an ADU in my backyard in Arlington?
Yes, you can build a detached ADU in your backyard in Arlington, as long as it is at least 6 ft from the rear property line and 6 ft from side lot lines. The remaining space within setbacks determines the maximum building footprint available.
What is the height limit for ADUs in Arlington?
ADUs in Arlington are limited to 25 feet in height, with a maximum of 2 stories. Height is typically measured from average finished grade to the peak of the roof.
Do ADU setbacks differ from the main house in Arlington?
ADU setback requirements in Arlington may differ from those for the main house. ADUs often have reduced setback requirements to make them feasible on existing lots. The Affordable Homes Act sets minimum standards that Arlington must allow.
Can I get a setback variance for my ADU in Arlington?
Setback variances are possible but not guaranteed in Arlington. You would need to apply to the zoning board of appeals and demonstrate a hardship — such as an unusually shaped lot or topographic constraints. Before pursuing a variance, verify your exact property dimensions against the setback requirements.
Where can I find all ADU regulations for Arlington?
Visit our complete ADU rules page for Arlington, MA for a full overview of zoning, permits, size limits, setbacks, parking, and costs. We cover all Massachusetts municipalities with data sourced from local ordinances and state law.
Check Your Address
See exactly what ADU rules apply to your specific property in Arlington.