Boston Needs ADUs
As a renter, I know there's no more pressing concern than housing. I hear it from my neighbors, and I hear it from all of you. We need to do more to keep Boston affordable, and I'm passionate about finding diverse solutions to our housing crisis.'
In September 2025, I filed a hearing order to legalize triple-deckers in Boston, and this week, I was proud to file another to legalize Accessory Dwelling Units (ADUs).
It’s time for Boston to join Mattapan and communities across the Commonwealth that have successfully updated their zoning to allow ADUs. This is a proven solution that works for Massachusetts—and for Boston—and it’s time to make it available to all Boston residents.
Today, I want to share a deeper dive into ADUs: their immense potential to address our housing shortage, the critical issues with our city's current zoning code that make building them so difficult, and the importance of fixing our zoning code so that homeowners can more easily create these flexible, low-cost homes.
What Are Accessory Dwelling Units (ADUs)?
Accessory Dwelling Units (ADUs) are small, self-contained homes on the same lot as a main residence.
ADUs may be attached (adjacent to a main building), detached (a separate stand-alone structure from the main building), or internal (located within the main building);
Put simply, they are smaller homes that can be built inside or alongside a main home—like a basement apartment or a backyard cottage. ADUs are a flexible housing option that can serve a wide range of people, from multi-generational families to downsizing seniors or young professionals.
They can help homeowners build wealth while providing much-needed, affordable living space.
Why Boston's ADU Policy Fails Property Owners
Currently, Boston’s zoning code is a major obstacle to building new housing, particularly for Accessory Dwelling Units (ADUs).
The city permits one internal ADU by right within a 1-, 2-, or 3-family home. However, if a homeowner wants to build an attached or detached ADU, they must go through the burdensome process of seeking a zoning variance from the City's Zoning Board of Appeal.
This requirement adds significant costs, legal fees, and administrative red tape, often taking months or even years to resolve. This complex process undermines the primary benefit of ADUs—creating affordable, low-barrier housing.
While the city of Mattapan has taken a proactive step by updating its neighborhood zoning to allow by-right ADUs, the rest of Boston lags behind.
Boston is the only exemption from Massachusetts’ 2024 statewide ADU law, which allows homeowners to add an ADU in single-family zoning districts in every one of the 350 cities and towns in Massachusetts.
Why do we need ADUs?
Boston's housing crisis is urgent, and the city's restrictive zoning has severely limited the creation of ADUs, with only 150 built between 2019 and May 2024.
Legalizing ADUs in all neighborhoods would be a vital step forward.
Creates Affordable Housing:
ADUs offer a low-cost housing alternative in a city with a high cost of living. They can help address the region's shortage of tens of thousands of homes and reduce the percentage of residents who are housing cost-burdened.
Supports Seniors and Families:
The American Association of Retired Persons (AARP) found that many homeowners over 50 would consider building an ADU to accommodate a loved one who needs care or to provide a home for family members.
ADUs offer a low-cost alternative to expensive assisted-living facilities, allowing elderly residents to "age in place" with family support. This is especially important for Boston's 82,000 elderly residents, many of whom have incomes below the poverty line or require assistance with daily living.
Additionally, ADUs offer a compassionate and practical option for families, allowing them to care for aging relatives or neighbors in a private setting, avoiding the burdensome costs and often impersonal environment of nursing homes.
Streamlines a Broken System:
Currently, Boston permits only internal ADUs "by right," while building an attached or detached ADU requires a costly and time-consuming zoning variance from the Zoning Board of Appeal.
This red tape undermines the benefit of creating affordable homes. Legalizing ADUs would simplify the process, making it easier for more homeowners to build them.
Builds Generational Wealth:
For homeowners, ADUs are a powerful tool for building wealth. The rental income from an ADU can help offset mortgage payments and other living expenses, providing a stable financial resource.
A legalized and streamlined process for building ADUs would empower more residents to use their property to build wealth for their families.
The legalization of ADUs is just one piece of the puzzle, but it’s a crucial one.
To truly tackle Boston’s housing crisis, we must embrace a diverse range of solutions, from large-scale developments to the legalization of smaller, more flexible housing options like ADUs and triple-deckers.
I am committed to continuing this work and pushing for a city that is more affordable and accessible for everyone.