Enabling Accessory Dwelling Units
The City of Boston is working to eliminate barriers to building Accessory Dwelling Units (ADUs) by updating zoning to make these small homes as-of-right citywide. An ADU is a smaller, independent unit inside your home or in your yard. ADUs can provide accessible, lower-cost housing options for families, young adults, seniors, and more. Whether you’re creating housing for a loved one, renting out for extra income, or downsizing to stay on your property, ADUs create more opportunities for residents.
ADU Guidebook
This guidebook offers a vision for Boston residents to address housing needs through Accessory Dwelling Units (ADUs), providing neighborhood-scale, incremental housing options that fit into Boston’s diverse neighborhoods.
It aims to inspire small property owners by showcasing ADU designs that are compatible with common Boston home types. These designs help owners explore ADU possibilities, showing realistically buildable options that can be adapted to meet specific needs, such as wheelchair accessibility.
While this guidebook does not contain pre-approved plans for immediate construction, it illustrates potential ADU configurations for typical small properties in Boston. Any ADU project inspired by these designs must still go through the usual permitting and review process, requiring homeowners to collaborate with design professionals and the Zoning Board of Appeal to secure the necessary approvals for a building permit.
Get Involved
Upcoming Meetings
This meeting is your opportunity to learn more about how ADUs can benefit your home and community. Whether you are in the early stages of exploring your options or ready to take the next step, we encourage you to attend and ask any questions you may have.
Previous Events
Wednesday, May 8, 2024
Presentation | Presentation Chat | Recording
Wednesday, March 13, 2024
Presentation | Recording
What Are Accessory Dwelling Units?
Accessory Dwelling Units (ADUs) are additional residential units that can be built within an existing home or outside of it, such as in a smaller detached dwelling. ADUs allow homeowners to utilize their property to its fullest potential and support a household as it grows and changes over the years. Homeowners may opt to build an ADU so that family members (such as an aging parent) can move close by, or to generate extra income through a rental unit.
ADUs are an important part of Boston’s housing production toolbox and can help ease Boston’s affordable housing crisis, by allowing homes to expand as families grow or relatives move in, and adding new rental units to neighborhoods.
The City currently allows owner-occupants to build an ADU using only existing space within their homes (such as within an unused attic or basement), without any exterior alterations. The Boston Home Center and the Mayor’s Office of Housing also offer financing support and technical assistance for homeowners interested in building an ADU. Learn more about ADUs and how to build one in Boston.
Residential Zoning Reform to Allow ADUs in Mattapan
Mattapan’s residential zoning code was recently amended to allow for the by-right development of ADUs, including detached ADUs, on owner-occupied residential lots. Guided by the planning recommendations for residential areas in PLAN: Mattapan, the most recent neighborhood plan, Mattapan’s new residential zoning modernizes the residential code to reflect existing building patterns, supports contextual small-scale housing development, and allows for the by-right development of ADUs on residential lots. You can read more about the zoning changes here.