Massachusetts Affordable Homes Act ADU Information
*We will continue to update this page as we learn more*
Photo credit: Mass Municipal Association
What does the new Massachusett’s ADU Law (in the Bond Bill) mean for your community?
All towns/cities in Massachusetts will need to allow ADUs of all kinds by February of 2025!
First, your town/city is either:
already in full compliance.
in partial compliance (e.g. allows detached ADUs that do not restrict to family).
not in compliance (e.g. does not allow detached ADUs or has family-only restrictions)
Towns have 180 days to update their rules. Over the next several months, the State will go through a “Rule Making Process” and write detailed specifications to help guide municipalities on what the law means for them.
Massachusett’s ADU Law FAQs
Will the Implementation Deadline Get Extended (like in Maine)?
Maybe…It is hard to tell, but there is no reason to wait to start the planning process.
As an example, Maine extended its deadline by a full year.
Can I build one right now?
No, but you should start planning as if you can!
What if the town denies my application in February or doesn’t comply with the law?
There are other ways. You may be able to secure a building permit from the state via the 40a or 40b process!
How big can the ADU be?
ADUs cannot be larger in gross floor area than ½ of the primary dwelling or 900 square feet, whichever is smaller.
What other restrictions can the town place on ADUs?
Towns can place “reasonable restrictions” on the ADUs. We expect “reasonable” to be better defined in the Rule Making Process.
Can I use the ADU as a Short Term Rental?
The town can restrict the rental length and define what a Short Term Rental is.
Can I rent my ADU to anyone?
Yes! The town cannot restrict rental use, except for Short Term Rentals.
Can the town require a special permit for a basic ADU?
No! ADUs that meet the general state requirements must be permitted by right without public hearings.
However, towns can continue to require special permits for larger ADUs which is practiced by several municipalities.
Do I need to live in the ADU or main house (Owner Occupancy)?
Under the new law, municipalities cannot require Owner Occupancy. This means you could buy a single family home, add an ADU, and rent both like a two-family home.
The law does require an additional parking space to be added to waive the owner occupancy requirements.
Can the town require parking?
No additional parking is required if the ADU is located at least .5 miles from a commuter rail station, subway station, ferry terminal, or bus station.
Can I build two ADUs?
Possibly. Towns can require special permits to build more than one ADU in a single family zoned district.
Where can I find more information?
The Affordable Home Act Passed!!! Over the next several weeks we will be udpating our local rules pages to reflect this.
In the meantime, join our Mailing List below to stay up to date on ADU rules in MA.