Although it’s been a year and a half since the Affordable Homes Act took effect, allowing Massachusetts property owners to construct accessory dwelling units (ADUs) by right in single-family zoning districts, the change in regulations has so far resulted in minimal housing growth in Franklin County.
Though the state law allows by-right ADUs of up to 900 square feet or half the square footage of the primary dwelling, whichever is smaller, individual communities have the flexibility to increase the size allowed by right and can impose some restrictions, such as stating ADUs cannot be used for short-term rentals. In the law’s first year, one ADU building permit was approved in Bernardston, one in Montague, one in Shelburne, two in Deerfield and six in Greenfield, according to data from the state Executive Office of Housing and Livable Communities.
The data also shows that Bernardston has received a second building permit application, and Sunderland received two building permit applications for ADUs. Five Franklin County towns did not respond to the state survey, and 14 towns are listed as not having received any building permit applications during that time period.
The ADUs that have already been approved in Franklin County account for 0.98% of the total 1,224 ADUs permitted in 217 communities statewide during the first year.
According to Gov. Maura Healey’s office, the top 10 communities for ADU approvals in 2025, excluding Boston, are Plymouth (34), Lawrence (32), Nantucket (27), Lowell (26), Milton (24), Somerville (24), Worcester (23), Methuen (21), Medford (19) and Fairhaven (18). An ADU tracker can be viewed at mass.gov/info-details/accessory-dwelling-unit-tracker.
In a statement, Healey said the data on ADU permitting shows progress toward increasing housing production in Massachusetts.
“ADUs are one of the most practical ways to add homes and lower costs. They allow older adults to age near their loved ones and young adults to live independently while starting their careers,” Healey said. “This first-year data shows homeowners are already starting to take advantage of our new law, and we’re going to keep making it easier and cheaper to build ADUs so we can bring down housing costs for everyone.”
Franklin Regional Council of Governments Housing and Livability Program Manager Megan Rhodes said FRCOG’s building inspectors, who work with towns that don’t have their own inspectors on staff, have seen a few building permit applications in the year and a half since building ADUs have been allowed by right, but not many.
“It’s a fabulous tool, but we didn’t think there would be a huge number of applications,” Rhodes said. “We’re not seeing a lot of them here, and that’s in part because they’re expensive to build.”
Bob Obear of Obear Construction Co., based in Millers Falls, said it can cost between $300,000 and $400,000 to build a larger ADU, which can be prohibitive to many. His company has worked on a few ADUs throughout the county and is currently working on one in Erving, but has not seen a lot of interest in the small residences.
“There’s been some, but unfortunately, the cost to construct these is high. … It’s more hype and noise than actual execution,” Obear said.
Obear said that for property owners who plan to rent out their ADU, the cost to build one is higher than they would be able to easily recoup through rent. He added that most of the ADUs he sees being constructed are for people who are not looking to rent them out, but rather are wanting to create a space for their aging parents to live in.
“I’m seeing more need-based interest than financial interest,” Obear said. “In terms of if we’re seeing people lining up for these things, we’re not.”
He noted that many communities had already been agreeable to allowing ADUs, and the Affordable Homes Act just changed the size limits and process. For example, he said Montague previously allowed accessory apartments, and earlier this year, the town updated its zoning bylaws to replace them with accessory dwelling units. In Montague, ADUs with a ground floor area of up to 900 square feet are allowed by right, and ADUs as large as 1,200 square feet can receive approval through a special permit.
Only a handful of towns across Franklin County have had updates to their bylaws approved by the Attorney General’s Municipal Law Unit, though bylaw amendments passed by other towns during their Annual Town Meetings this past spring are being reviewed.
Until towns bring their bylaws into compliance with the Affordable Homes Act, state law trumps local regulations, allowing people to construct ADUs of up to 900 square feet by right in single-family zoning districts. Rhodes said the Franklin County communities that have not updated their bylaws are working to do so, but are in no rush, as they are not seeing a lot of interest from housing developers.
“About half of our towns have passed bylaws. There are some that are still mulling over what they want it to look like,” Rhodes said. “And a lot of towns that haven’t [passed bylaws] don’t see a lot of developmental pressures. … It’s on everyone’s minds.”
To help property owners in building ADUs, the state launched a loan program offering low-interest loans of up to $250,000 for detached ADUs and up to $150,000 for attached ADUs.
Obear said these loans can “soften the upfront cost” of building an ADU, but still have to be paid back, and in Franklin County, where rents are lower than in the eastern part of the state, it can be difficult for property owners to make a profit from an ADU.
Still, he noted that every person’s situation is different and, if financially feasible, investing in one’s property is always a smart move.
“I don’t see a big rush for it — maybe in some wealthier communities there is,” Obear said. “But I don’t feel like in Franklin County their rents are going to offset the costs.”
To assist residents in understanding whether an ADU is feasible for their property, the state recently announced a Massachusetts ADU Resource Center, and the Mass Clean Energy Center launched a Pioneer Valley ADU Accelerator.
The Pioneer Valley ADU Accelerator works with property owners in Hampden, Hampshire and Franklin counties to determine the feasibility of building an ADU. The program offers no-cost, one-on-one support to evaluate site conditions, zoning, cost and next steps, with a focus on all-electric ADUs. The website, at goclean.masscec.com/adu/pioneer-valley, includes pre-designed ADU options in a variety of sizes.
“Many homeowners are interested in building an ADU, but feel overwhelmed by the process or don’t know where to begin,” Lt. Gov. Kim Driscoll said in a statement. “The ADU Resource Center and Pioneer Valley ADU Accelerator will give residents clear guidance, practical tools and direct support so they can move forward with confidence while helping communities create more housing options.”
Looking ahead, both Obear and Rhodes said they think more property owners will look to build ADUs, but they don’t believe Franklin County is going to become overrun with them, or that it will make a huge difference in the housing inventory.
“I think there’ll be a steady uptick as people understand what these are and what’s available,” Rhodes said. “It’s a tool, but I don’t think it’s gonna transform our housing landscape.”
