Governor Maura Healey announced a new campaign to make it easier and cheaper for people across Massachusetts to build accessory dwelling units (ADUs). ADUs, also known as granny flats or in-law apartments, are small residential living spaces that are located on the same lot as another home. Governor Healey’s Affordable Homes Act allowed ADUs to be built-by-right in single-family zoning districts statewide, giving communities an effective tool to increase housing production and lower costs.

In the first six months after the law went into effect, cities and towns across the state reported nearly 900 applications for ADUs thanks to statewide simplification of the permitting process. To further build on this progress, the Healey-Driscoll Administration is launching three new initiatives to help Massachusetts homeowners design, finance and build ADUs.

• Design: The Executive Office of Housing and Livable Communities (HLC) will launch its ADU Design Challenge on December 15, offering prize funding through sponsorship partners to generate a set of publicly available, replicable designs that homeowners and communities can use at no cost.
• Support: Backed by $10 million from the Governor’s fiscal 2026-2030 Capital Investment Plan, Massachusetts Housing Partnership (MHP) will offer a program to help more homeowners build ADUs.
• Finance: Following its recent authorization of $20 million for mission-oriented homeownership activities, MassHousing plans utilize a portion of those funds to introduce affordable, accessible construction financing for low and moderate-income homeowners beginning in 2026.

Launching December 15, the ADU Design Challenge will invite designers, architects and other design professionals to submit replicable, high-quality ADU prototypes that can be adapted by homeowners and local builders. The Design Challenge will reduce predevelopment costs by making strong designs publicly available, streamline permitting by encouraging compliant designs and promote innovation by including sustainable materials, climate-resilient design, and accessible layouts that support the needs of aging residents and families. The Design Challenge is being sponsored by Eastern Bank Foundation, the Boston Foundation, AIA Massachusetts, and MHP, with roughly $60,000 – $70,000 in sponsor commitments to support the challenge, prizes and outreach. Design winners will be announced late April of next year, and additional details will be released as final design and submission requirements are completed.

In addition to the Design Challenge, the Healey-Driscoll Administration is working to make ADU production more affordable for families who want and need access to the opportunities these homes provide. Supported by $10 million over two years from the Governor’s fiscal 2026–2030 Capital Investment Plan, MHP is developing a statewide ADU Incentive Program to promote ADU construction and support homeowners through the predevelopment and construction process.

The program will also focus on identifying and addressing remaining barriers to ADU development beyond zoning, providing insight for future statewide policy and program design. MHP anticipates this initiative will support the creation of hundreds of ADUs in its first two years and inform the next phase of policy and investment. MHP plans to hold stakeholder information sessions this January with the full program launching in spring 2026.

To further address the financing barriers that can prevent homeowners from constructing an ADU, MassHousing is leveraging its experience as the state’s housing finance and investment bank to develop a new ADU construction loan program. This month, MassHousing authorized up to $20 million for mission-oriented homeownership activities, a portion of which will support the ADU loan program. The program is expected to provide low-cost subordinate mortgage loans designed to finance ADU construction, targeted toward low- and moderate-income homeowners who may not be able to access home equity financing. This financial support is anticipated to be available in early 2026.