Back to top
Last updated: 4/16/19

Additional Dwelling Unit Pilot

We want to streamline the process for homeowners looking to create an additional unit.

This 18-month pilot program allows owner occupants in East Boston, Mattapan, and Jamaica Plain to carve out space within their homes to create smaller, independent units, known as Additional Dwelling Units (ADUs).

The goal of the program is to develop more natural affordable housing options while creating rental income for homeowners. We want homeowners to take advantage of the existing space in their homes, which can help people age in place and prevent displacement.

If you're interested in learning more or applying to the pilot program, check out the information below:  

Additional Dwelling Unit Toolkit

ADU Overview - Citywide Presentation


BOSTON, MA 02108-2501
Have questions or comments?

Why we did this

Two top priorities for Mayor Walsh and the City of Boston include:

  • lowering the cost of living in Boston, and
  • preventing displacement.

We think we can address both priorities through our pilot. Owner occupants can carve out space in their home to create a smaller rental unit. Those looking for an apartment gain more options. Homeowners stretched thin by the cost of living in Boston gain income.

The experiment

We want to see if these units will increase affordable housing options in Boston neighborhoods. We hope to create safe living environments and support family arrangements. We also hope this will help aging homeowners remain in their homes. Based on the results of the pilot, we’ll find out the impact these units have on affordability and displacement. We’ll also get a better idea of the impact of expanding the program. Our final presentation to the Zoning Commission has more information.

Pilot details

Pilot Zoning and Eligibility

We crafted the zoning language for the pilot with the help of the Boston Planning & Development Agency. The agency's board approved the amendment, which you can read here. The Mayor signed off on the language in November 2017.

To qualify for a unit, your home must be:

  • three units or less
  • owner-occupied, and
  • in one of the pilot neighborhoods: East Boston, Mattapan, and Jamaica Plain.
Additional Dwelling Unit Toolkit

As part of this program, we are developing an Additional Dwelling Unit Toolkit. It will be a guide for homeowners who would like to build their own unit. We’ll walk homeowners through the permitting, design, financing, and construction processes. We want to make sure all interested and eligible homeowners can take advantage of this pilot. We plan to release the toolkit in February 2018.

Additional Dwelling Unit toolkit

Additional Dwelling Unit Loan program

We also plan to offer limited financial support to homeowners looking to build an Additional Dwelling Unit. A zero-interest, deferred equity loan up to $30,000 will be available for eligible homeowners through the Boston Home Center's Additional Dwelling Unit Pilot Loan Program.

Pilot Details

Results and lessons learned

The ADU pilot program has helped many residents, including older adults interested in aging in place and staying in their neighborhoods, provide new housing for family members and renters. These ADU pilot program participants ranged in age, income, race and ethnicity. In addition, many residents want the program to expand to other Boston neighborhoods.

You can learn more about the ADU Pilot Program and what's next in the ADU Pilot Program Report.