Zoning & Size Limits
| Requirement | Quincy, MA | Newton, MA |
|---|
| Allowed Zones | One ADU by right in single-family zoning districts (internal | All zones allowing single-family use (by right per MGL c.40A |
| Max Size (Detached) | 900 sq ft or 50% of the principal structure's gross floor area (per 760 CMR 71.02), whichever is less; minimum 320 sq ft for a detached ADU | 1,000 sq ft or 50% of the main building by right; 1,200 sq ft in an existing garage or if the owner occupies the site; up to 1,500 sq ft by special permit |
| Max Size (Attached) | 900 sq ft or 50% of the principal structure's gross floor area, whichever is less | Internal/attached: up to 1,000 sq ft (1,200 sq ft for conversions within existing homes), max 50% of the main building's floor area |
| Max Height | Detached ADUs limited to one story (city guideline | Detached: 2.5 stories with standard new-house setb |
| Parking Required | 1 additional off-street space required only if the ADU is ou | No additional parking required (state law caps at 1 space an |
| Owner Occupancy | Not allowed — prohibited statewide by the Affordable Homes A | Not required for by-right ADUs (prohibited by state law); re |
Setback Requirements
| Setback | Quincy, MA | Newton, MA |
|---|
| Rear Setback | Detached ADUs must meet the principal-structure yard setbacks in QZO Table 4.1 — varies by district; Confirm with Quincy Inspectional Services | 5 ft for a 1.5-story/22-ft detached ADU; standard principal-dwelling setbacks for taller units |
| Side Setback | Per QZO Table 4.1 (district-specific) — Confirm with Quincy Inspectional Services | 5 ft for a 1.5-story/22-ft detached ADU; standard principal-dwelling setbacks for taller units |
| Front Setback | Per QZO Table 4.1 (district-specific) — Confirm wi | Per underlying zone — Confirm with Newton Planning |
Permits & Timeline
| Detail | Quincy, MA | Newton, MA |
|---|
| Permit Timeline | Standard building-permit review; typically 4-8 weeks — Confirm with Quincy Inspectional Services | Building permit typically 4-8 weeks; special-permit route adds roughly 3-6 months — Confirm with Newton Planning Department |
| Permit Fees | Valuation-based building permit fee — Confirm with Quincy Inspectional Services | Building permit fees based on construction value — Confirm with Newton Inspectional Services |
| Impact Fees | None listed in the ADU guidelines — Confirm with Quincy Insp | No ADU-specific impact fees identified — Confirm with Newton |
| Pre-Approved Plans | None — Quincy does not offer a pre-approved ADU pl | Not available |
Construction Costs
| Cost | Quincy, MA | Newton, MA |
|---|
| Avg Build Cost | $250,000-$425,000 | $250,000-$450,000 |
| Cost Per Sq Ft | $350-$550 | $250-$450 |
| Garage Conversion | $150,000-$250,000 | $120,000-$220,000 |
| Prefab ADU | $180,000-$350,000 installed (site work, foundation, and utility connections extra — confirm with manufacturer) | $150,000-$320,000 |
Rental Income Potential
| Rental | Quincy, MA | Newton, MA |
|---|
| 1BR Avg Rent | $2,200-$2,700/mo | $2,500-$3,300/mo |
| 2BR Avg Rent | $2,700-$3,300/mo | $3,100-$4,200/mo |
| Short-Term Rentals | No — Quincy's ADU guidelines expressly prohibit using an ADU | No — minimum 30-day rental/occupancy term for ADUs |
| Est. ROI | 5-8% annual return | 4-6% annual return |
Which City Is Better for ADUs?
Quincy scores 6/10 while Newton 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.
Finance Your ADU Project
Most ADU projects are funded through HELOCs, construction loans, or cash-out refinancing. Compare rates from top lenders.
Some links on this page are affiliate links. We may earn a commission at no extra cost to you. Learn more
Get Quotes in Your City
Connect with licensed ADU contractors and get free quotes for your project.