ADU Rules: Quincy vs Wellesley
How do adu rules rules compare between Quincy, MA and Wellesley, MA?
Quincy and Wellesley have similar restriction levels.
Quincy, MA
Norfolk County
Quincy allows ADUs by right under MGL c. 40A §3 and the 2024 Affordable Homes Act. One ADU per single-family lot is allowed as internal, addition, or detached unit. Maximum size is 50% of principal dwelling or 900 sq ft, whichever is less. Minimum size is 320 sq ft for detached units.
View full Quincy rules →Wellesley, MA
Norfolk County
Wellesley regulates ADUs under Section 5.13 of the Wellesley Zoning Bylaw. At the April 2025 Annual Town Meeting, Wellesley adopted Article 40.1 to amend its ADU bylaw, and the Massachusetts Attorney General approved the changes effective April 15, 2025. As of April 15, 2025, detached ADUs are permitted by-right in Single Residence Districts; a Special Permit is no longer required, consistent with the state Affordable Homes Act.
View full Wellesley rules →Key Facts Comparison
| Fact | Quincy | Wellesley |
|---|---|---|
| Code | Quincy ZO + MGL c. 40A §3 | - |
| Maximum Size | 900 sq ft or 50% of principal, whichever is less | - |
| Minimum Size (detached) | 320 sq ft | - |
| Allowed Types | Internal, addition, or detached | - |
| Additional Parking Required? | No | - |
| Local Code | - | Wellesley Zoning Bylaw §5.13 |
| Amendment | - | Art. 40.1 (April 2025 ATM) |
| AG Approval | - | April 15, 2025 |
| Detached ADUs | - | By-right (no Special Permit) |
| Annual Certificate | - | Required from Planning Dept. |
Highlighted rows indicate differences between cities.
Quincy FAQ
Can I build an ADU on my property in Quincy?
Quincy allows ADUs by right under MGL c. 40A §3 and the 2024 Affordable Homes Act. One ADU per single-family lot is allowed as internal, addition, or detached unit. Maximum size is 50% of principal dwelling or 900 sq ft, whichever is less. Minimum size is 320 sq ft for detached units.
What are the size limits for an accessory dwelling unit in Quincy?
Code: Quincy ZO + MGL c. 40A §3. Maximum Size: 900 sq ft or 50% of principal, whichever is less. Minimum Size (detached): 320 sq ft. Allowed Types: Internal, addition, or detached.
Wellesley FAQ
Are detached ADUs allowed by-right in Wellesley?
Yes, as of April 15, 2025. The Massachusetts Attorney General approved Wellesley's Article 40.1 bylaw amendment, removing the Special Permit requirement for detached ADUs in Single Residence Districts. A building permit and annual Certificate of Compliance are still required.
How big can a Wellesley ADU be?
Under §5.13 and the MA Affordable Homes Act (G.L. c. 40A as amended), an ADU is capped at 900 sq ft or 50% of the primary dwelling's gross floor area, whichever is smaller.
Does Wellesley require an annual filing for ADUs?
Yes. Wellesley §5.13 requires an annual Certificate of Compliance (Notice of Accessory Unit) from the Planning Department in addition to the initial building permit from the Inspector of Buildings.
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