Image: A home in Marblehead, MA. Source: Todd Kent on Unsplash.
What the Massachusetts Affordable Homes Act Means for the State’s Homeowners, Renters, and Municipalities
The Affordable Homes Act provides one HUGE way a homeowner can fully take advantage of their property. This is to create a separate dwelling that individuals, families, or relatives can live in.
These are commonly known as “in-law apartments” or “in-law suites.” Naturally, some homeowners do invite their in-laws to live in these spaces. Many others would prefer to rent spaces out to people, for profit, instead. This would require a self-contained dwelling, commonly known as an “accessory dwelling unit” or ADU.
These types of separate dwellings aren’t unheard of in Massachusetts. They are however often difficult to create due to regulations and zoning restrictions. That all changed in 2024.
The Affordable Homes Act: backstory
Until 2024, many municipalities prohibited separate dwelling units entirely on individual properties or heavily restricted them, especially in districts designated for single-family homes. In municipalities where ADUs were allowed, local governments often required special permits and discretionary zoning approvals, only allowed family members of the homeowner to live in them, or had strict occupancy requirements.
This made the process of establishing an ADU costly and difficult for homeowners.
That all changed in 2024 when the Massachusetts House of Representatives passed Bill H.4138, the Affordable Homes Act. Here, we’ll explore what the new law means for both homeowners and renters. We’ll also look at what steps municipalities are taking to adapt to it.
What Does the Massachusetts Affordable Homes Act Say?
Governor Maura Healey of Massachusetts signed the Affordable Homes Act into law on August 6, 2024. It authorized $5.16 billion in spending over five years. It also includes 50 new policy initiatives designed to counter rising housing costs in the state.
According to the mass.gov page devoted to the new law:
“The bill includes unprecedented authorizations in modernizing the state’s public housing system. It boosts programs that support first-time homebuyers and homeownership, and resources to build more housing for low to moderate-income residents. It also includes many policy changes that will unlock housing production in our state. Including allowing accessory dwelling units, support for the conversion of vacant commercial space to housing, and support for sustainable and green housing initiatives.”
Most importantly, the law allows homeowners to create an ADU of up to 900 square feet on their properties by right in all cities and towns in Massachusetts.
That means homeowners no longer need special permission to create or rent out separate dwellings on their property.
This part of the law took effect on Sunday, February 2, 2025, after the government published its final ADU regulations (760 CMR 71.00) on January 31, 2025. As of that date, the state considers any local zoning provisions that conflict with the state ADU rules to be unenforceable, according to mass.gov.
In practical terms, that means a homeowner whose ADU plans meet the state definition and size limits can now expect their application to be processed under the state framework, even if their town’s bylaw has not yet been fully updated.
Chapter 150 of the Affordable Homes Act
You can find the relevant portion of the law regarding accessory dwelling units in Chapter 150, Sections 7 and 8. Although this section of the law represents a relatively small policy change, it could have significant implications for homeowners and renters in the state.
Section 7 Strikes Out the Previous ADU Definition
Section 7 of that chapter of the law officially “strikes out” the previous definition of “accessory dwelling unit” (ADU). It replaces it with a new one.
The new definition says an ADU is now considered “a self-contained housing unit, inclusive of sleeping, cooking, and sanitary facilities on the same lot as a principal dwelling, subject to otherwise dimensional and parking requirements.”
The state’s ADU regulation and guidance clarify that ADUs must be allowed by right on most single‑family lots that already have a lawful home. Towns and municipalities cannot block them at the local level with additional minimum lot size rules or separate utility hookup requirements.
Based on this new definition, a legal ADU must:
- Have a separate entrance to the outside, either directly or through a shared corridor that meets state building requirements for safe egress.
- Have a floor area no larger than one-half the gross floor area of the principal dwelling, or 900 square feet, whichever is smaller.
- Be subject to applicable rules from the municipality, such as size restrictions, prohibitions on short-term rentals, etc.
The changes also stipulate that no municipality can unreasonably restrict the creation or rental of an ADU. Provided that ADU is not a short-term rental.
Section 8 Addresses Local Zoning Regulations
Meanwhile, Section 8 of Chapter 150 addresses zoning regulations concerning ADUs in single-family residential districts. It prohibits the prohibition, undue restriction, or requirement of a special permit for the use of land or structures for a single ADU or its rental.
It also states that the owner of the property need not occupy the primary dwelling or the ADU itself. Also, the owner needs only one additional parking space, unless the location is a half mile or less from public transit.
What the Affordable Homes Act Means for Buyers and Renters
The most significant impact of this law will be on homeowners, prospective homebuyers, and renters in Massachusetts. The City of Boston is the only city or town not included in the statewide law.
The Impact on Homeowners and Homebuyers
Ideally, the law gives homeowners the ability to do more with their properties. It also creates opportunities to more easily provide housing for family members. It increases property values without as much red tape to get through as before.
We spoke with Danvers Planning Director Brian Szekely in Fall 2024, when this story was still new. According to him at the time, ADUs by right were “a potential revenue stream for homeowners who are willing to rent out a unit.” Homeowners could use that revenue to defray the cost of their mortgages or supplement their household income.
However, “The cost of creating an ADU is not cheap,” said Szekely. Unlike previous “in-law” apartments or suites, ADUs must meet the specific requirements listed above and be completely separated from the original home. They don’t necessarily need to be separate buildings, but they do need a separate entrance and must be “self-reliant, firewalled, and fully autonomous,” as Szekely put it.
In addition to the new rules regarding ADUs, the law also includes programs that may make homeownership more accessible to some Massachusetts residents. According to an overview of the law, some other provisions include:
- $425M for the Housing Stabilization and Investment Fund to support preservation, new construction, and rehabilitation projects.
- $175M for the HousingWorks Infrastructure Program to fund municipal infrastructure projects to encourage denser housing development.
- Creating a new Homeownership Tax Credit designed to produce homes affordable to first-time homebuyers earning not more than 120% of the area median income (AMI).
The Impact on Renters
The primary purpose of the new law is to expand the number of rental units in Massachusetts by making it much simpler for homeowners to add small, self‑contained units to existing properties.
By September 2025, cities and towns reported roughly 840 ADU applications statewide, of which at least 550 the state had approved. However, that is still only a fraction of the 8,000 to 10,000 ADUs the state estimated property owners could build over the next five years under the new framework.
So far, the pattern matches what many advocates expected: early adopters are moving forward, and the real test will be whether more typical homeowners decide that building an ADU is worth the time and money.
More Housing Opportunities for Tenants and Family Members
Speaking of Danvers, Szekely said the law could “allow two populations to more easily live together in town.” In this instance, he is referring to younger renters who don’t have as many rental options in town. Long-time residents of Danvers could feasibly create new rental units.
“There are young professionals who grew up here but can’t live here. There aren’t enough opportunities for renters or first-time homebuyers,” he said. “This law may not change the affordability of units in the area, but it could lead to more availability for this population.”
Some residents may also create ADUs specifically to house family members. “If long-time residents create ADUs, more young professionals could live closer to their parents or their extended families,” said Szekely.
More Housing Opportunities for “Down-sizing Elders”
Szekely also believed that more ADUs in the Danvers area could benefit the population of “down-sizing elders.”
“There are people who have been here their entire lives but are ready to downsize and sell their homes. They want to stay, but they don’t have enough options because there aren’t enough new multi-family projects,” he said. “This creates an option for them to get an affordable rental and stay in their communities.”
Szekely suggested that if older people choose to downsize and move into ADUs, it could even have an “echo effect” on single-family home availability in the area. “When aging adults are moving into ADUs, that frees up larger houses for families who are trying to get in.”
Overall, these changes could lead to even more rental availability in the state over the next several years.
The Impact on Housing Availability and Affordability Overall
Housing scarcity and lack of affordability have long been significant problems in Massachusetts. A June 2024 poll by UMass Amherst and WCVB found that 34% of Massachusetts residents viewed “the housing crisis” as the most important issue they’d like the state legislature to address over the next year. These respondents also said the biggest barrier to buying or renting was “finding something in my price range.” They most supported allowing accessory dwelling units to be built on single-family properties.
The law is likely good news for renters, as it could significantly expand the number of dwelling units across the state.
According to a report by The Commonwealth Beacon, the state estimates that the zoning changes created by the law could create more than 8,000 accessory dwelling units over the next five years. That might not sound like much, but a report by The Boston Globe said that some 950,000 homes in Massachusetts could accommodate an ADU.
Potential Issues and Challenges with the Affordable Homes Act
Although the Affordable Homes Act will result in some significant benefits for homeowners and renters, it may also result in challenges.
Updating Municipality Bylaws
The most pressing challenge for municipalities will be complying with the law. Updating their existing regulations to be synchronized with the new rules will not be easy.
When the law was newly passed in 2024, Szekely and the town of Danvers were exploring how they could update town bylaws to comply with ADU requirements. Szekely expected this to be an extensive process at the time. Although Danvers created rules regarding “Extended Family Living Areas” (EFLAs) years ago, those rules “fly in the face of what the new law prohibits,” said Szekely.
As of this writing (December 2025), Danvers’ EFLA information is still live on its website. The town’s zoning bylaws page currently hosts Bylaws from 2024 (PDF).
The town’s rules state that only the owner’s family members can inhabit EFLAs. Also, they must not be a self-contained unit and must be attached to the original home for by-right projects. As they currently stand, existing EFLAs in Danvers can’t be easily transitioned into ADUs. That will be a challenge for homeowners who created EFLAs, but who may wish to transition them into ADUs.
“What do we do with all these houses that have EFLAs that aren’t up to building code for ADUs?” asked Szekely. “How do we bless them? Is there an administrative process that will allow them to continue being used in their current state? These are the questions we’re currently asking.”
A Public Process
Changing bylaws “will be a public process in which the town will determine how we’ll regulate ADUs. And what we’ll do about nonconformities, such as if a homeowner decides to make one larger than 900 square feet or if they aren’t self-contained,” said Szekely.
Since the original publication of this article, the Executive Office of Housing and Livable Communities has issued final ADU regulations and implementation FAQs for cities and towns.
Localities don’t need to rewrite their bylaws overnight. However, communities must adjust their procedures so that ADU applications that meet the state definition and limits can move forward. They can do this even while they clean up their local bylaw language.
Concerns from Residents and Homeowners
There is also the possibility that some homeowners won’t appreciate new rental units materializing in their neighborhoods. Any substantial increases in population in specific areas could also put a strain on local services.
“I’ve heard concerns that this law will ‘turn single-family homes into duplexes,’” said Szekely. “I’ve also heard concerns that the town won’t have the infrastructure to support an influx of new residents.”
However, Szekely didn’t anticipate that the changes would be so substantial as to reshape the entire fabric of the community. So far, the early pace of ADU construction has been measured. Even with hundreds of new applications in 2025, statewide approvals remain well below what would dramatically change the look and feel of most neighborhoods.
Furthermore, many homeowners were and are excited about the law and what it could mean for their families. It creates more opportunities for them to live closer to their adult children, their grandparents, or other extended family members without having to completely share a living space.
“I’ve also heard people say, ‘Great, now I can get grandma and grandpa here to help with the kids,’” said Szekely.
Governor Healey’s 2025 Push to Make ADUs Easier and Cheaper
In late 2025, Governor Maura Healey launched a new campaign to make it easier and cheaper for Massachusetts homeowners to design, finance, and build ADUs. While the Affordable Homes Act changed the zoning rules, many homeowners still had questions about where to start and how to pay for construction.
The new campaign aims to close that gap. State officials highlighted three main initiatives:
ADU Design Challenge
The Executive Office of Housing and Livable Communities is running an “ADU Design Challenge.” The goal is to generate a library of ready-to-use, code-compliant ADU plans that homeowners and communities can access at no cost.
The state believes these template designs will cut down on pre-development time and architectural expenses. They may also promote energy-efficient, accessible layouts that work for aging parents, adult children, or renters.
Statewide ADU Incentive Program
Backed by 10 million dollars in state capital funding over two years, the Massachusetts Housing Partnership (MHP) is developing a statewide ADU Incentive Program. Authorities expect the program to launch fully in 2026, providing technical assistance and more affordable financing options to help homeowners navigate design, permitting, and construction.
Homeowner Education and Support
The administration is also focusing on outreach and homeowner education, answering basic questions like “Where do I start?” and “How do I pay for this?” and helping residents understand how an ADU might support multigenerational living, downsizing, or long-term rental income.
Looking to Buy a Home in Massachusetts?
The Affordable Homes Act opened new possibilities for homebuyers by expanding the housing inventory through the addition of accessory dwelling units. It also created new opportunities to expand the use of single-family properties.
Buyers can engage with local municipalities to understand how these new laws might impact housing options in their desired areas, as well as how they can create an ADU if they choose to do so.
As always, feel free to contact us at GoldCoast Mortgage for additional information about homebuying and homeownership in the Bay State.
Additional Resources:
In October 2024, Attorney Chris Vaccaro with Daton & Finegold also spoke to the new Massachusetts Affordable Homes Act (AHA) HERE.