Accessory Structures in Lowell, MA (2026)

City of Lowell, Accessory Dwelling Units (ADUs) program page; M.G.L. c.40A, S.1A & S.3 (per Ch. 150, Acts of 2024)

An ADU is a small residential living space located on the same lot as another home. ADUs can be internal within the existing primary structure on a site, external as an addition to the existing structure, or detached within a new or existing accessory structure on a site (such as a detached garage or carriage house). The maximum size for an ADU is 900 square feet OR 50% of the Gross Floor Area ...

City of Lowell, Storage Shed Permits (Development Services guidance under the Massachusetts State Building Code)

Storage sheds that exceed 200 square feet require building permits. A shed no more than 200 square feet in area and 16 feet in height may be located within the side and rear yard setbacks, however, it must be at least 10 feet from the dwelling. A shed of up to 200 square feet is small enough so as not to require a foundation, but it must still be anchored to the ground to prevent wind-related o...

City of Lowell, Apply for Permits & Accessory Dwelling Units pages (Massachusetts State Building Code, 780 CMR)

Per the Massachusetts State Building Code, a building permit is required to construct, reconstruct, alter, repair, remove or demolish a structure; or to change the use or occupancy of a building or structure. [ADU guidance:] ADUs can be internal within the existing primary structure on a site, external as an addition to the existing structure, or detached within a new or existing accessory stru...