Hampden County, MA Accessory Structures: ADU Rules (2026)

The Affordable Homes Act, signed August 6, 2024 (Chapter 150 of the Acts of 2024), amended M.G.L. c. 40A §3 to require every city and town in Massachusetts to permit one ADU by-right on every lot zoned for single-family residential use. The statute states that no zoning ordinance shall 'prohibit, unreasonably restrict or require a special permit or other discretionary zoning approval' for a single ADU on a single-family lot. The Executive Office of Housing and Livable Communities (EOHLC) issued implementing regulations at 760 CMR 71.00 effective February 2, 2025. Key statewide standards: (1) Both owner-occupancy and rental are permitted — municipalities cannot require the owner to live on-site, but they may prohibit short-term rental (under 31 days) of the ADU. (2) Maximum one additional parking space may be required, and zero parking spaces if the lot is within 0.5 miles of a transit stop (commuter rail, subway, ferry, or bus station). PVTA bus service in Springfield/Holyoke/Chicopee may trigger this transit exemption. (3) Additional ADUs beyond the first may still require a special permit. (4) Reasonable regulations such as setbacks, height, and site plan review are allowed but cannot make ADUs infeasible. Hampden County government was abolished in 1998 (M.G.L. c. 34B §1); all permitting is handled by each town's building department and zoning board of appeals (e.g., Springfield Office of Planning and Economic Development, Holyoke Building Department).