ADU Rules: Bellingham vs Brookline
How do adu rules rules compare between Bellingham, MA and Brookline, MA?
Bellingham and Brookline have similar restriction levels.
Bellingham, MA
Norfolk County
Massachusetts 2024 Affordable Homes Act (MGL c. 40A §3) grants property owners the right to build ADUs on owner-occupied lots by right. Cities and towns cannot ban ADUs but may regulate size (up to 900 sq ft for internal ADUs). Norfolk County has no additional ADU rules.
View full Bellingham rules →Brookline, MA
Norfolk County
Brookline updated its ADU bylaw (§ 4.05) in 2024 to comply with MGL c. 40A §3. One ADU by right on single-family lots is allowed up to 900 sq ft or 50% of principal floor area. Owner-occupancy requirements removed. FAR cap for ADUs eliminated.
View full Brookline rules →Key Facts Comparison
| Fact | Bellingham | Brookline |
|---|---|---|
| State Law | MGL c. 40A §3 — Affordable Homes Act 2024 | - |
| ADUs by Right | Yes — on owner-occupied single-family lots | - |
| Max Size (Internal) | Up to 900 sq ft (municipalities may limit) | - |
| Bans Allowed? | No — cities cannot ban ADUs under new state law | - |
| County ADU Rule? | None — regulated by state law and each town | - |
| Code Section | - | Brookline ZO § 4.05 (2024 amendment) |
| Maximum Size | - | 900 sq ft or 50% of principal GFA |
| Owner-Occupancy | - | No longer required |
| Parking | - | Max 1 space; exempt within 0.5 mi of transit |
| Architecture | - | Must match principal dwelling style |
Highlighted rows indicate differences between cities.
Bellingham FAQ
Can I build an ADU on my property in Norfolk County?
Massachusetts 2024 Affordable Homes Act (MGL c. 40A §3) grants property owners the right to build ADUs on owner-occupied lots by right. Cities and towns cannot ban ADUs but may regulate size (up to 900 sq ft for internal ADUs). Norfolk County has no additional ADU rules.
What are the size limits for an accessory dwelling unit in Norfolk County?
State Law: MGL c. 40A §3 — Affordable Homes Act 2024. ADUs by Right: Yes — on owner-occupied single-family lots. Max Size (Internal): Up to 900 sq ft (municipalities may limit). Bans Allowed?: No — cities cannot ban ADUs under new state law.
Brookline FAQ
Can I build an ADU on my property in Brookline?
Brookline updated its ADU bylaw (§ 4.05) in 2024 to comply with MGL c. 40A §3. One ADU by right on single-family lots is allowed up to 900 sq ft or 50% of principal floor area. Owner-occupancy requirements removed. FAR cap for ADUs eliminated.
What are the size limits for an accessory dwelling unit in Brookline?
Code Section: Brookline ZO § 4.05 (2024 amendment). Maximum Size: 900 sq ft or 50% of principal GFA. Owner-Occupancy: No longer required. Parking: Max 1 space; exempt within 0.5 mi of transit.
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