AGrannio

Can You Build an ADU in Worcester?

Yes — Worcester is governed by Massachusetts's statewide ADU law, which limits what the city can restrict. A 700 sq ft detached ADU here runs about $185,000–$302,500.

Construction costs in Worcester track close to the Massachusetts state average.

Detached ADU (700 sq ft)

$185,000–$302,500

Garage conversion (400 sq ft)

$57,500–$105,500

Statewide protection

Yes

What applies in Worcester

Massachusetts's statewide standard (Affordable Homes Act, M.G.L. c.40A §3 (2024)) is the starting point, but parcel-level rules, fees and design review are set locally. Confirm those details with Worcester before design.

Estimate your Worcester ADU cost

Your property

ADU type

Estimated cost in Massachusetts

$185,000 – $302,500

≈ $264–$432/sq ft turnkey · midpoint $244,000

$165,900
Construction
$43,900
Design & permits
$34,200
Site work
Good news — building an ADU in Massachusetts is very likely allowed.
  • ✓Size within the guaranteed minimum. Your 700 sq ft ADU is at or under the 900 sq ft your city must allow regardless of other rules.
  • ✓No extra parking likely required. Set by local ordinance — commonly 1 space per ADU unless near transit.
  • ✓No owner-occupancy requirement. You can rent out both the main home and the ADU — you do not have to live on the property.
  • ✓Lot has room. A 700 sq ft ADU uses about 12% of your 6,000 sq ft lot — comfortably within typical coverage limits.

Rule basis: Affordable Homes Act, M.G.L. c.40A §3 (2024)

If you rent it out

$1,275–$2,100

est. rent/mo

8.4%

gross yield

12.9 yrs

payback

~$18,972/yr after a 7% vacancy allowance, before financing & maintenance.

Financed over 20 yrs at 7.5%, the build is about $1,966/mo — vs ~$1,700/mo in estimated rent.

Get your detailed feasibility report →

Estimates are for planning only and are based on regional construction-cost indices and published statewide ADU statutes. Local ordinances, lot conditions and contractor pricing vary — always confirm with your city planning department and a licensed contractor.

Get matched with a vetted ADU builder in Worcester

Tell us about your project and we'll introduce you to a builder who works in your area. Free, no obligation.

Other Massachusetts cities

BostonSpringfieldCambridgeLowellSomerville

Estimates are for planning only and are based on regional construction-cost indices and published statewide ADU statutes. Local ordinances, lot conditions and contractor pricing vary — always confirm with your city planning department and a licensed contractor.