An ADU is a secondary living space, located on the same lot as the primary single-family home. It could be within the existing home, such as a basement or attic conversion. It could be attached to the residence, or it could be detached such as a cottage or converted garage. Through the years, ADUs have been known as inlaw suites, backyard bungalows, carriage houses, guest houses, granny flats, and more.
According to AARP, accessory dwelling units expand housing options that are affordable and flexible for people of all ages. It provides smaller, economical units in a market that typically sees big houses being built, when small houses are needed. They also make use of existing infrastructure and housing stock, so they are environmentally friendly and respectful of a neighborhood’s pace and style. The AARP suggests many ideas to encourage ADUs, one of which is for local zoning to allow all ADU types, detached, attached, or interior.
The State of Massachusetts agrees and recently passed legislation (Section 8, Chapter 150 of the Acts of 2024), amending the Zoning Act to allow ADUs to be constructed by right in single-family districts.
The Town of Billerica is now drafting a zoning amendment for Spring 2025 Town Meeting to match.
The existing Zoning Bylaw currently allows “inlaw suites”, and requires that they be attached only, no larger than 800sf, occupied by relatives only, and approved only by Special Permit Review by the Zoning Board of Appeals.