Lunenburg, MA Accessory Structures: Tiny Homes (2026)

Massachusetts does not have a unified 'tiny home' statute. Regulation depends on structure classification. Foundation-built tiny homes are dwellings under 780 CMR (MA State Building Code, 10th Edition). Requirements: (1) minimum habitable room size 70 sq ft under 780 CMR 1208, with at least one room minimum 120 sq ft (as of 10th Ed, reduced from earlier standards); (2) minimum ceiling height 7 feet in habitable space, 6'8" in kitchens/bathrooms; (3) full code compliance including insulation (IECC), mechanical ventilation, smoke/CO per MGL c. 148, §26F, egress windows. 780 CMR Appendix AQ (Tiny Houses) has been referenced but not formally adopted in MA. Tiny homes on wheels (THOW) are classified as recreational vehicles under 540 CMR 2.00 (Registry of Motor Vehicles) and cannot legally serve as a primary dwelling in most zoning districts. RV parks regulated by 105 CMR 440 (Recreational Camps for Children and Mobile Home Parks) and local zoning. The Affordable Homes Act (Ch. 150 Acts of 2024, §8) effective February 2, 2025 allows ADUs up to 900 sq ft or 50% of principal dwelling GFA (whichever is less) by-right in single-family zones statewide — this provides a significant tiny home pathway in Worcester County. ADUs can be detached (cottage/tiny home style), converted garages, basement/attic conversions, or additions. Many Worcester County towns (Worcester, Shrewsbury, Westborough, Grafton) are updating zoning to comply with ADU law. Utility connections, septic (if rural) under 310 CMR 15.00 Title 5, and building code compliance required.