Tiny Homes: Arlington vs Cambridge
How do tiny homes rules compare between Arlington, MA and Cambridge, MA?
Arlington and Cambridge have similar restriction levels.
Arlington, MA
Middlesex County
Middlesex County has no tiny-home ordinance because the county government was abolished in 1997. Massachusetts adopted Appendix Q (tiny houses on permanent foundations, 400 sq ft or less) into 780 CMR effective January 1, 2020. Whether a tiny home is allowed in a specific Middlesex town depends entirely on that town's local zoning bylaw, which controls minimum dwelling size, lot area, and accessory-dwelling-unit standards.
View full Arlington rules →Cambridge, MA
Middlesex County
Tiny homes on foundations are allowed as ADUs in Cambridge under MGL c.40A s.3A. Tiny homes on wheels are treated as recreational vehicles and cannot be used as permanent dwellings under the MA State Building Code.
View full Cambridge rules →Key Facts Comparison
| Fact | Arlington | Cambridge |
|---|---|---|
| County Government | Abolished 1997 | - |
| Appendix Q Effective | January 1, 2020 | - |
| Appendix Q Size Limit | 400 sq ft or less | - |
| On Wheels | Not covered by Appendix Q | - |
| ADU by Right | Up to 900 sq ft (Ch. 150/2024) | - |
| Tiny home on foundation | - | Allowed as ADU |
| Max ADU size | - | 900 sq ft |
| Tiny home on wheels | - | Not allowed as dwelling |
| Governing code | - | 780 CMR and c.40A s.3A |
| Park model units | - | Not permitted in Cambridge |
Highlighted rows indicate differences between cities.
Arlington FAQ
Can I build a tiny house in Middlesex County, Massachusetts?
There is no county-level tiny home rule because Middlesex County government was abolished in 1997. Massachusetts adopted Appendix Q of the state building code (780 CMR) effective January 1, 2020, which covers permanent-foundation tiny houses 400 sq ft or less. Whether you can build one depends on the local zoning bylaw of your specific town (Cambridge, Lowell, Newton, etc.); check with that town's planning department.
Are tiny homes on wheels legal in Middlesex County towns?
Generally no. Massachusetts Appendix Q only covers tiny houses on permanent foundations. Tiny houses on wheels are treated as recreational vehicles, and most Middlesex County towns do not allow RVs as a primary dwelling under their zoning bylaws. The 2024 Affordable Homes Act allows ADUs up to 900 sq ft by right in single-family zones, which gives more flexibility for accessory tiny dwellings on a foundation.
Cambridge FAQ
Can I park a tiny house on wheels in my Cambridge driveway?
Not as a dwelling. THOWs are treated as RVs and cannot be used for long-term living under state code.
Can I build a 600 sq ft tiny home as an ADU?
Yes, with a foundation and full building permit it qualifies under the state ADU law.
Compare other topics
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