Newton, MA Accessory Structures: ADU Owner Occupancy (2026)

Sec. 1(E) sets the rules for Detached Accessory Dwelling Units. A detached ADU is capped at 1,000 square feet or 50% of the principal dwelling's total gross floor area, whichever is less, under Sec. 1(E)(2), and the City Council can grant a special permit for a larger unit up to 1,500 square feet under subsection (b). Subsection (d) creates a narrower by-right path for a detached ADU between 1,000 and 1,200 square feet, so long as it stays under 50% of the combined floor area, without needing that special permit, but only if three conditions in Sec.

1(E)(2)(d)(i)-(iii) are met. The first, (E)(2)(d)(i), requires that the property owner or an indirect property owner occupy either the principal dwelling unit or the Accessory Dwelling Unit, and defines indirect ownership to include a beneficiary of a trust holding record title, or a majority owner of the voting stock of a corporation or the membership units of an LLC holding record title. The other two conditions back up the occupancy rule: under (ii), a new owner must notify the Commissioner of Inspectional Services within 30 days of any transfer, triggering a compliance review against Sec.

1 and the state building code, 780 CMR; and under (iii), the owner must file a sworn certification of continued compliance every January 1 or upon transfer, with the property subject to inspection.