Sandwich, MA
Sandwich, MA Accessory Dwelling Unit (ADU) Rules
Last updated: 11.17.2025
What You Need to Know
Sandwich, like all of Massachusetts since the passage of the 2024 Affordable Homes Act, allows ADUs by right. Each town has slightly different rules surrounding ADUs, but they all must adhere to the framework outlined by the state. The rules for Sandwich are outlined below.
Type of ADU Permit Required
ADUs in Sandwich do not require special permits, and can be built using a traditional building permit. Residents are allowed to build one ADU per single-family home.
ADU Rules
Accessory Dwelling Units (ADUs)
An ADU can be maximum 900 square feet, or half the Gross Floor Area of the main house; whichever is smaller.
ADUs can be attached, detached, or built within the main house.
ADUs must have a separate entrance from the main house.
Attached ADUs can share an entry hall with the main house, but need a separate entry within the entry hall.
Properties within ½ mile of a transit station do not require additional parking.
Properties outside of that area require one additional off-street parking spot.
Short-term rentals are not allowed. The minimum rental period for an ADU in Sandwich is twelve months.
The main house and ADU must be owned by the same person(s).
ADUs must have at least 1 dedicated parking space unless the ADU is within 0.5 miles from a transit station.
ADUs must remain in common ownership.
Resources: https://www.sandwichmass.org/DocumentCenter/View/10628/May-2025-Zoning-Bylaw (See pages 37-38)