ADU rules in Chelsea, MA — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
ADUs are now allowed by right in Chelsea under Massachusetts Affordable Homes Act (Ch. 150, Acts of 2024, §8, effective Feb 2, 2025). Max 900 sq ft or 50% of principal dwelling. Chelsea's Planning Board was developing a local ADU ordinance in early 2025 to implement the state mandate, with design review retained.
The MA Affordable Homes Act preempts local ADU bans in single-family zoning districts. Chelsea previously did not allow ADUs under its zoning ordinance. A draft local ADU ordinance was under review by the Chelsea Planning Board as of January 2025, proposing to allow ADUs by right in any district permitting single-family homes, max one per parcel, subject to design review. No additional parking required within 0.5 miles of MBTA transit stations; 1 space required beyond that distance.
Building permits required. Non-compliant ADUs face zoning and building code enforcement.
Chelsea, MA
Construction noise regulated under Chelsea Code Ch. 16 and MassDEP 310 CMR 7.10. Standard hours are Mon–Fri 7 AM–6 PM, Sat 8 AM–5 PM; no construction on Sund...
Chelsea, MA
Barking dogs addressed under Chelsea Code Ch. 4 (Animals) and general nuisance provisions. Excessive barking is a civil nuisance complaint under MGL c. 140. ...
Chelsea, MA
Chelsea enforces noise complaints through Chapter 16 (Miscellaneous Offenses). No single statewide decibel limit applies; the city relies on MassDEP 310 CMR ...
Chelsea, MA
Chelsea is in the flight path of Boston Logan International Airport (about 1 mile west). Aircraft noise is governed by federal FAA regulations and Massport; ...
Chelsea, MA
Chelsea has a citywide residential parking sticker program under Code §13-4.2. The Chelsea Waterfront District requires sticker parking 8 AM–6 PM Mon–Fri. St...
Chelsea, MA
Abandoned vehicles on public ways subject to state law MGL c. 90 §22C (72-hour threshold). Chelsea enforces through its ISD and Police Department. Inoperable...
Side-by-side rule comparisons with other cities in Suffolk County.
See how other cities in Suffolk County handle adu rules.
See how Chelsea's adu rules rules stack up against other locations.
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