Chelmsford, MA
Chelmsford, MA Accessory Dwelling Unit (ADU) Rules
City Acceptance Rating: 2/10 (10 is most accepting)
Last updated: 9.10.2024
Source: Town of Chelmsford Facebook
What You Need To Know
Currently not in compliance with the Massachusetts Affordable Homes Act.
Currently, Chelmsford allows a form of an ADU that is referred to as a Limited Accessory Apartment (LAA). These can only be constructed within or attached to a single family dwelling.
Type of ADU Permit Required
To construct an ADU within an existing dwelling, a building permit through the building inspector is required. A special permit is required to build an ADU attached to the existing home.
ADU Rules
An LAA as defined in Chelmsford is a self-contained unit within an owner-occupied single-family dwelling, providing space for bathing, cooking, and sleeping, and used exclusively by extended family members. It does not convert the dwelling into a two-family unit.
The LAA must have separate ingress/egress that maintains the single-family appearance. New entrances should be at the side or rear, with enclosed staircases and internal doorways between the LAA and the main unit.
The LAA size is limited to 750 square feet, excluding stairs and common areas.
Adequate off-street parking required, consistent with neighborhood character. Utilities must be connected to town sewer, and separate metering is not required unless mandated by the State Building Code.
Only one LAA per lot and can have no more than two occupants.
LAAs must be used only by extended family. Use restrictions must be recorded in the Registry of Deeds and include provisions for owner-occupancy and notice to potential buyers.
The Building Inspector issues permits by right. Special permits are handled by the Zoning Board of Appeals, which also records restrictions in the Registry of Deeds.
Applicants must submit architectural plans, site plans, names of residents, and an executed use restriction.
Special permits are based on zoning bylaws. The Zoning Board of Appeals may allow deviations for accessibility features.
New owners must file applications and inspections will ensure compliance. Violations may result in permit lapses, fines, and required special permits for continued use.