Framingham, MA Accessory Structures: ADU Rules (2026)

Section 435-12C of the Code of the City of Framingham, added by Order No. 2023-077-002, sets the zoning framework for accessory dwelling units in the City's single-family neighborhoods. An ADU cannot be built or converted without a special permit, and the Zoning Board of Appeals sits as the special permit granting authority for every application, reviewing floor plans of both the ADU and the principal residence before it decides. Size is capped at whichever is smaller of 900 square feet or half the floor area of the principal dwelling, and the unit must be a complete, separate housekeeping unit with its own sleeping, cooking, and sanitary facilities.

Occupancy is limited to two people and two bedrooms, and the property must provide at least one additional off-street parking space beyond what the primary dwelling already requires. No ADU can be held in separate ownership from the main house, and § 435-12C(4)(f) bars any dimensional-regulation variance from being granted for an ADU, so the lot must otherwise meet the City's normal setback, height, and lot-coverage standards. Once the ZBA grants the special permit, the owner still needs a building permit from the Building Commissioner, who administers and enforces the section going forward, including issuing violations and fines for noncompliant units and keeping a yearly citywide inventory.

Occupancy permits run for two-year terms and must be renewed as long as the ADU and its ownership stay compliant with the special permit and the State Building Code, 780 CMR.