Zoning & Size Limits
| Requirement | Boston, MA | Worcester, MA |
|---|
| Allowed Zones | Select residential zones | Residential zones A and B |
| Max Size (Detached) | 900 sq ft or 50% of living area (whichever is less) | 850 sq ft |
| Max Size (Attached) | 900 sq ft or 50% of living area (whichever is less) | 900 sq ft |
| Max Height | 35 feet | 30 feet |
| Parking Required | 1 space per unit | 1 space per unit |
| Owner Occupancy | May be required in some zones | Not required (MA Affordable Homes Act, effective Jan 31, 202 |
Setback Requirements
| Setback | Boston, MA | Worcester, MA |
|---|
| Rear Setback | 20 feet | 20 feet |
| Side Setback | 5 feet | 5 feet |
| Front Setback | 20 feet | 20 feet |
Permits & Timeline
| Detail | Boston, MA | Worcester, MA |
|---|
| Permit Timeline | 90-150 days | 60-80 days |
| Permit Fees | $4,500-$7,500 | $2,800-$4,500 |
| Impact Fees | $2,000-$3,500 | $1,000-$1,800 |
| Pre-Approved Plans | Not available | Not available |
Construction Costs
| Cost | Boston, MA | Worcester, MA |
|---|
| Avg Build Cost | $200,000-$400,000 | $140,000-$280,000 |
| Cost Per Sq Ft | $220-$440 | $165-$330 |
| Garage Conversion | $100,000-$220,000 | $70,000-$160,000 |
| Prefab ADU | $150,000-$320,000 | $110,000-$250,000 |
Rental Income Potential
| Rental | Boston, MA | Worcester, MA |
|---|
| 1BR Avg Rent | $1,800-$2,400/mo | $1,250-$1,650/mo |
| 2BR Avg Rent | $2,200-$3,200/mo | $1,550-$2,150/mo |
| Short-Term Rentals | Not permitted | Not permitted |
| Est. ROI | 5-7% annual return | 7-10% annual return |
Which City Is Better for ADUs?
Boston scores 6/10 while Worcester scores 6/10 on our ADU-friendliness index.
Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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