Canton ADU feasibility

Rules cited for Canton

• One protected ADU is allowed by right on a lot in a district that allows a single-family house by right or by special permit. A second unit needs a special permit.
• The by-right gross floor area is the smaller of 900 square feet and half the principal dwelling. A town cannot set a lower cap, and it may allow a larger unit.
• The town cannot require the owner to live in either unit, and it cannot require a family relationship.
• Parking is at most one extra space. If any part of the lot is within 0.5 miles of a commuter rail station, subway station, ferry terminal, or bus station, no extra space may be required.
• Setbacks, coverage, open space, bulk, height, and stories cannot be stricter than the most permissive standard for the principal dwelling, a single-family dwelling, or an accessory structure. A minimum lot size and a floor-area ratio for the protected unit are not allowed.
• Canton is covered by the state rule. The EOHLC FAQ cites the Attorney General’s June 4, 2025 Canton decision for the point that a town cannot require a minimum lot size for a protected ADU.

• Mass.gov, Accessory Dwelling Units
• Mass.gov, Chapter 150, Sections 7 and 8 of the Acts of 2024
• 760 CMR 71.00, Protected Use Accessory Dwelling Units (EOHLC)
• EOHLC Accessory Dwelling Unit FAQs