Zoning & Size Limits
| Requirement | Worcester, MA | Boston, MA |
|---|
| Allowed Zones | Residential zones A and B | Interior ADUs as-of-right in owner-occupied 1-3 family homes |
| Max Size (Detached) | 900 sq ft or 50% of primary dwelling, whichever is less | Not as-of-right — ZBA variance required (by-right only in Mattapan) |
| Max Size (Attached) | 900 sq ft or 50% of primary dwelling, whichever is less | Not as-of-right — ZBA variance required (by-right only in Mattapan) |
| Max Height | 30 feet | 35 feet |
| Parking Required | No additional parking required for an ADU (existing required | None required for an interior ADU |
| Owner Occupancy | Not required (owner need not live on the property; prohibite | Required (owner-occupied 1-3 family home; condos and LLCs in |
Setback Requirements
| Setback | Worcester, MA | Boston, MA |
|---|
| Rear Setback | 20 feet | 20 feet (applies to variance/Mattapan detached units) |
| Side Setback | 5 feet | 5 feet (applies to variance/Mattapan detached units) |
| Front Setback | 20 feet | 20 feet (applies to variance/Mattapan detached uni |
Permits & Timeline
| Detail | Worcester, MA | Boston, MA |
|---|
| Permit Timeline | 60-80 days | 90-150 days |
| Permit Fees | $2,800-$4,500 | $4,500-$7,500 |
| Impact Fees | $1,000-$1,800 | $2,000-$3,500 |
| Pre-Approved Plans | Not available | Not available |
Construction Costs
| Cost | Worcester, MA | Boston, MA |
|---|
| Avg Build Cost | $140,000-$280,000 | $200,000-$400,000 |
| Cost Per Sq Ft | $165-$330 | $220-$440 |
| Garage Conversion | $70,000-$160,000 | $100,000-$220,000 |
| Prefab ADU | $110,000-$250,000 | $150,000-$320,000 |
Rental Income Potential
| Rental | Worcester, MA | Boston, MA |
|---|
| 1BR Avg Rent | $1,250-$1,650/mo | $1,800-$2,400/mo |
| 2BR Avg Rent | $1,550-$2,150/mo | $2,200-$3,200/mo |
| Short-Term Rentals | Not permitted | Not permitted |
| Est. ROI | 7-10% annual return | 5-7% annual return |
Which City Is Better for ADUs?
Worcester scores 6/10 while Boston scores 5/10 on our ADU-friendliness index.
Worcester edges ahead overall. Both cities offer viable ADU development opportunities — the best choice depends on your specific property, budget, and goals.
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