Massachusetts is known for its historic neighborhoods, coastal towns, and tight housing market. With prices climbing and families looking for flexible living options, Accessory Dwelling Units (ADUs) are suddenly front and center across the state.
Thanks to the Affordable Homes Act, ADUs are now allowed by right statewide (with Boston operating under its own zoning system). That means in most Massachusetts cities and towns, adding a small backyard cottage, in-law suite, or above-garage apartment is far more straightforward than it used to be.
If you’re thinking about building an ADU on your property in Massachusetts, understanding the rules around size, placement, building codes, and permits is the first step. Zook Cabins is here to walk you through the essentials so you can move forward with confidence.
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Are ADUs Allowed in Massachusetts?
Yes, ADUs are officially allowed in Massachusetts statewide, thanks to the 2024 Affordable Homes Act, which took effect on February 2, 2025. This new law requires every city and town to permit at least one Accessory Dwelling Unit by right on single-family residential lots, meaning homeowners no longer need a special permit or public hearing to add a secondary living space on their property. Massachusetts defines a by-right ADU as a self-contained unit up to 900 sq. ft. or 50% of the main home’s floor area (whichever is smaller), and it must meet standard building, safety, and zoning requirements such as setbacks, height limits, and utility connections.
While local governments can still regulate placement and design details, they cannot ban ADUs outright or create barriers that prevent homeowners from building one. In short, Massachusetts now has one of the most uniform, straightforward ADU laws in the country. It easier than ever for homeowners to add rental income, create multigenerational living options, or expand their property’s usable space without navigating complicated permits.
What Is Considered An ADU in Massachusetts?
In Massachusetts, an Accessory Dwelling Unit (ADU) is simply a second small home on the same property as your main house. It must be a fully independent living space with its own kitchen, bathroom, sleeping area, and separate entrance. ADUs can be created in several ways, such as a finished basement apartment, an attached home addition, or a detached backyard cottage. To qualify under the state’s new ADU law, the unit must be 900 sq. ft. or smaller, or no more than 50% of your main home’s size. As long as the space functions like its own small home and meets building code requirements, Massachusetts considers it an ADU, giving homeowners a flexible option for rentals, guest space, or multigenerational living.
Can Park Model ADUs Be Used As ADUs?
In Massachusetts, park model homes can be used as ADUs, but only if they meet the same standards as a permanent residential dwelling. Most park models are built to RV codes, which means they aren’t automatically approved as ADUs under the state’s by-right ADU law. To qualify, the unit must be placed on a permanent foundation, connected to utilities, and upgraded to meet residential building-code requirements for insulation, structural safety, and egress.
As long as those conditions are met and the unit stays within the state’s ADU size limit of 900 sq. ft. or 50% of the main home’s floor area, a park model can function as a fully compliant accessory dwelling unit. In short, a park model isn’t automatically an ADU in Massachusetts, but with proper installation and code upgrades, it can become one.
Can Log Cabins Be Used As An ADU?
Yes, log cabins can be used as ADUs in Massachusetts, as long as they meet the state’s building and zoning requirements for a permanent accessory dwelling unit. The new statewide ADU law allows one by-right ADU per single-family lot, but the structure must be built to full residential code, not recreational or seasonal standards. This means your log cabin must sit on a permanent foundation, include full utilities, and meet requirements for insulation, energy efficiency, plumbing, electrical, and safe egress.
As long as the cabin functions as a complete living space with its own kitchen, bathroom, and sleeping area and stays within the state’s ADU size limit of up to 900 sq. ft. or 50% of the main home’s floor area, Massachusetts will treat it as a compliant ADU. For many homeowners, a small log cabin offers a warm, character-filled option that fits perfectly within the state’s updated ADU regulations.
Can Modern Cabins Be Used As An ADU?
Yes, modern cabins can absolutely be used as ADUs in Massachusetts, as long as they meet the same requirements any accessory dwelling unit must follow under the state’s new ADU law. Massachusetts allows one ADU by-right on single-family lots, but the structure must be built to full residential building code, not temporary or recreational standards. As long as your modern cabin sits on a permanent foundation, includes proper insulation, plumbing, electrical, heating, and safe egress, it can qualify as a fully compliant ADU.
Modern cabin designs actually work extremely well within the state’s ADU rules, especially since most models fall comfortably under the size limit of 900 sq. ft. or 50% of the main home’s floor area. If the cabin is designed as a true, year-round living space then Massachusetts treats it the same as any other residential ADU, giving homeowners a stylish, contemporary option that fits perfectly into the updated regulations.
What is the Difference Between a Prefab ADU & a Modular ADU?
A prefab ADU is built as one complete unit in a factory and delivered fully assembled, while a modular ADU is built in multiple factory-made sections that are transported separately and put together on-site. Both count as ADUs in Massachusetts as long as they meet residential building code, but prefab units offer faster installation and modular units offer more layout flexibility.
What is the Minimum Size for an Accessory Dwelling Unit?
Massachusetts does not set a statewide minimum square footage for an Accessory Dwelling Unit (ADU) beyond meeting standard residential building-code requirements.
That said, local jurisdictions may impose their own minimums. For example:
- The City of Salem’s ordinance states ADUs must be at least 350 sq ft.
- The City of Quincy provides a minimum size for detached ADUs of 320 sq ft.
Bottom line: While Massachusetts law focuses on maximum size limits (900 sq ft or 50% of the primary home’s floor area), you should check your specific city or town zoning code for any local minimum size requirement before designing your ADU.
Can My ADU be Bigger Than My House?
No, your ADU cannot be bigger than your main house in Massachusetts. Under the statewide ADU law, the maximum size for a by-right ADU is 900 sq. ft. or 50% of your primary home’s floor area, whichever is smaller. This rule ensures the ADU stays a secondary structure and doesn’t dominate the main dwelling. So even if your lot is large enough to fit a bigger unit, Massachusetts requires the ADU to remain clearly smaller than the primary residence.
How Close To My House Can I Build An ADU?
Massachusetts allows ADUs by right, but each city or town keeps control over setbacks, which determine how far the ADU must be from property lines and other structures, including your main home.
Most Massachusetts towns require an ADU to follow the same setbacks as other accessory structures, which typically means:
- 10–15 ft from the primary house
- 10–20 ft from side or rear property lines
- 25–30 ft from the front property line
Some towns allow even smaller setbacks for attached or internal ADUs, since they are physically connected to the main house.
Do You Need A Permit For An ADU in Massachusetts?
Yes, you need a permit to build an ADU in Massachusetts. Even though ADUs are now allowed by-right statewide, every project must go through the local building and zoning review process before construction begins. “By-right” simply means you don’t need a special permit or public hearing, but you still need standard approvals like a building permit, zoning compliance check, and separate electrical, plumbing, and mechanical permits.
Most towns will also require a site plan showing where the ADU will sit and final inspections before you can legally occupy the unit. Your town must also approve it once it passes building and safety code requirements.
Are There Any Incentives or Grants for ADUs in Massachusetts?
Yes, Massachusetts does offer incentives and grants to make building an ADU more affordable. The most popular option is the Home Modification Loan Program (HMLP), which gives homeowners 0% interest loans up to $50,000 to create safe, accessible living spaces, often including ADUs for aging parents or family members with disabilities. The state also launched a $5 million ADU Incentive Program to help cover design and construction costs for qualifying homeowners.
Some cities offer additional assistance as well. Boston provides a $7,500 design grant, plus 0% interest loans of up to $50,000, specifically for ADU projects. While eligibility varies, Massachusetts is one of the few states actively helping residents finance ADUs, making it easier and more affordable for homeowners to get started.
Are Zook Cabin’s ADUs Built to Code?
Yes, all Zook Cabin ADUs are built to code and designed to meet Massachusetts regulations. With years of knowledge and experience with ADUs, our designers and builders craft each ADU with local building codes in mind, ensuring that each aspect meets and exceeds your building codes.
Can an ADU Have Multiple Bedrooms and Bathrooms?
Yes, an ADU in Massachusetts can have multiple bedrooms and bathrooms as long as it fits within the statewide size limit of 900 sq. ft. or 50% of the main home. The law doesn’t restrict layout, so you’re free to include one or two bedrooms and more than one bathroom, as long as the ADU meets plumbing, electrical, and safety codes.
If you’re interested in an ADU with multiple bedrooms or bathrooms, Zook Cabin’s Grove, Luna, and A-Frame ADUs all offer 1-2 bedroom options.
Are ADUs A Good Investment?
Yes, ADUs are considered a very strong investment for most homeowners. A well-designed ADU can generate steady rental income, boost your property value, and create long-term flexibility for multigenerational living or downsizing.
In many markets, ADUs increase a home’s value by 10%–30%, and rental ADUs often provide some of the highest ROI in residential real estate because the land is already paid for. They also offer built-in resilience: you can use the space for guests, aging parents, or future rental income whenever you need it. Between added equity, passive income potential, and long-term versatility, ADUs tend to outperform most other home upgrades in terms of financial return.
What Counties in Massachusetts Allow ADUs?
Does Barnstable County allow ADUs?
Yes, Barnstable County does allow ADUs, and most towns across Cape Cod follow the statewide Massachusetts rule that permits one by-right ADU on any single-family lot. Homeowners can build an internal, attached, or detached ADU as long as it meets the state size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
Local cities and towns in Barnstable County may add their own requirements, but they cannot ban ADUs outright under the new state law. In short, if your ADU meets Massachusetts building codes and follows your town’s zoning standards, you can build an ADU anywhere in Barnstable County.
Does Berkshire County Allow ADUs?
Yes, Berkshire County does allow ADUs, thanks to Massachusetts’ new statewide ADU law that requires every city and town to permit at least one accessory dwelling unit on a single-family property. In Berkshire County, this opens the door for homeowners to add a small rental unit, guest space, or multigenerational suite without going through a lengthy special-permit process.
The only statewide limit you must follow is the size cap of 900 sq. ft. or 50% of the main home’s floor area, and local towns may layer on their own rules for things like setbacks, septic capacity, lot coverage, or architectural style. Because many Berkshire towns are still updating their zoning bylaws to align with the state law, exact requirements can vary, but ADUs are now allowed county-wide for anyone who meets building code and basic zoning standards.
Does Bristol County Allow ADUs?
Yes! Bristol County allows ADUs, and homeowners across the county can now build one by-right thanks to Massachusetts’ statewide ADU law. Whether you’re in Fall River, New Bedford, Attleboro, or any nearby town, you’re permitted to add an attached, internal, or detached ADU on a single-family lot as long as it follows the state size limit of no more than 900 sq. ft. or 50% of your main home’s floor area.
Local cities and towns may still apply their own rules, but they cannot prohibit ADUs outright under the new law. This makes Bristol County a flexible region for adding rental income, multigenerational living space, or a small guest cottage, as long as your project meets building-code and zoning standards.
Does Dukes County Allow ADUs?
Yes, Dukes County does allow ADUs, and every island town on Martha’s Vineyard must follow Massachusetts’ new statewide rule permitting one by-right ADU on any single-family lot. Homeowners in places like Edgartown, Oak Bluffs, Chilmark, and Vineyard Haven can build an internal, attached, or detached ADU as long as it meets the state size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
Local towns may still require septic reviews, architectural compatibility, or specific setbacks because of the island’s sensitive environmental standards, but they can’t ban ADUs outright under the new law. In short, if your ADU meets building code and fits within your town’s zoning guidelines, Dukes County fully allows it.
Does Essex County Allow ADUs?
Yes, Essex County allows ADUs, and every city and town in the county must follow Massachusetts’ statewide rule that permits one by-right ADU on any single-family lot. From Salem and Beverly to Andover, Lynn, and Gloucester, homeowners can build an attached, internal, or detached ADU as long as it meets the state’s size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
While local zoning boards still review details like setbacks, parking, and septic capacity, they can’t prohibit ADUs outright under the new law. So whether you’re planning a rental unit, guest suite, or space for family, Essex County fully allows ADUs as long as your project meets building code and your town’s basic zoning requirements.
Does Franklin County Allow ADUs?
Yes, Franklin County allows ADUs, and every town in the county must follow Massachusetts’ statewide rule that permits one by-right ADU on any single-family property. Whether you’re in Greenfield, Deerfield, Montague, or one of the small rural towns, you can build an internal, attached, or detached ADU as long as it fits within the state’s size cap of up to 900 sq. ft. or 50% of your main home’s floor area.
Local zoning boards may still review things like setbacks, septic capacity, and general site layout, but they cannot prohibit ADUs outright. For homeowners in Franklin County, this makes adding a rental unit or multigenerational living space both doable and straightforward, as long as the ADU meets building-code and local zoning requirements.
Does Hampden County Allow ADUs?
Yes, Hampden County allows ADUs, and every city and town in the county must follow Massachusetts’ statewide rule that permits one by-right ADU on single-family lots. Homeowners in places like Springfield, Westfield, Chicopee, and Longmeadow can build an attached, internal, or detached ADU as long as it meets the state’s size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
While local zoning boards can still review details such as setbacks, parking, and septic or utility capacity, they can’t ban ADUs outright under the new statewide law. For Hampden County residents, this means adding a rental unit, in-law suite, or backyard cottage is fully allowed as long as it meets building-code and basic zoning requirements.
Does Hampshire County Allow ADUs?
Yes, Hampshire County allows ADUs, and every town in the county now follows Massachusetts’ statewide rule that permits one by-right ADU on single-family properties. Whether you’re in Northampton, Amherst, Easthampton, or any of the smaller hill towns, you can build an ADU as long as it meets the state’s size limit of up to 900 sq. ft. or 50% of your main home’s floor area.
Local zoning boards may still apply rules for setbacks, septic capacity, and general site design, but they can’t prohibit ADUs outright under the new law. This makes Hampshire County a flexible area for adding a rental unit, backyard cottage, or in-law suite, as long as your project complies with building code and your town’s basic zoning standards.
Does Middlesex County Allow ADUs?
Yes, Middlesex County allows ADUs, and every town in the county follows Massachusetts’ statewide rule that permits one by-right ADU on any single-family lot. This means homeowners in communities like Cambridge, Somerville, Newton, Framingham, Lowell, and the many smaller suburban towns can build an internal, attached, or detached ADU without needing a special permit, as long as the unit stays within the state’s size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
Local boards may still review setbacks, parking, utility or septic capacity, and overall site design, but they can’t prohibit ADUs outright under the new law. For Middlesex County homeowners, adding a rental unit or in-law suite is fully allowed as long as the ADU meets building-code and zoning requirements.
Does Nantucket County Allow ADUs?
Yes, Nantucket County allows ADUs, and the island follows Massachusetts’ statewide rule that permits one by-right ADU on any single-family lot. Homeowners can build an internal, attached, or detached ADU as long as it meets the state size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
Since Nantucket has unique factors local zoning may include extra steps such as architectural approval or wastewater review. However, the town cannot ban ADUs outright under the new state law. As long as your project meets building code and fits within Nantucket’s zoning standards, ADUs are fully allowed on the island.
Does Norfolk County Allow ADUs?
Yes, Norfolk County allows ADUs, and every town in the county must now follow Massachusetts’ statewide rule that permits one by-right ADU on any single-family lot. Whether you’re in Quincy, Brookline, Dedham, Milton, or smaller suburban towns like Norfolk and Walpole, you can build an internal, attached, or detached ADU as long as it stays within the state’s size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
Local zoning boards may still review things like setbacks, utility or septic capacity, and overall site layout, but they cannot ban ADUs outright under the new law. This makes Norfolk County a practical and flexible place for adding a rental unit, backyard cottage, or in-law suite, as long as your project meets building code and local zoning requirements.
Does Plymouth County Allow ADUs?
Yes, Plymouth County allows ADUs, and every town in the county must follow Massachusetts’ statewide rule permitting one by-right ADU on any single-family lot. Whether you’re in Plymouth, Brockton, Hingham, Middleborough, or any of the surrounding communities, you can build an attached, internal, or detached ADU as long as it meets the state size limit of up to 900 sq. ft. or 50% of your main home’s floor area.
Local zoning boards may still review things like setbacks, parking, septic capacity, and design standards, but they can’t prohibit ADUs outright under the new law. For homeowners throughout Plymouth County, adding a backyard cottage, guest suite, or small rental unit is fully allowed as long as the project meets building-code and local zoning requirements.
Does Suffolk County Allow ADUs?
Yes, Suffolk County allows ADUs, and every city in the county follows Massachusetts’ statewide rule permitting one by-right ADU on any single-family lot. Homeowners in Boston, Chelsea, Revere, and Winthrop can build an internal, attached, or detached ADU as long as it meets the state size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
While these urban communities may add their own requirements they cannot ban ADUs outright under the new law. This makes Suffolk County a strong area for adding a small rental unit, in-law suite, or backyard cottage, as long as your ADU complies with building code and your city’s zoning guidelines.
Does Worcester County Allow ADUs?
Yes, Worcester County allows ADUs, and every town in the county now follows Massachusetts’ statewide rule permitting one by-right ADU on any single-family lot. Whether you’re in Worcester, Shrewsbury, Leominster, Fitchburg, or one of the county’s many small rural towns, you can build an internal, attached, or detached ADU as long as it meets the state’s size cap of up to 900 sq. ft. or 50% of your main home’s floor area.
Local zoning boards may still review details like setbacks, parking, septic or utility capacity, and overall design, but they can’t prohibit ADUs outright under the new law. This makes Worcester County a flexible and ADU-friendly area for adding a rental unit, guest house, or multigenerational living space, as long as the project meets building-code and zoning requirements.
Accessory Dwelling Unit Requirements by Municipalities
Does Boston Allow ADUs?
Yes, Boston does allow ADUs as the law now follows Massachusetts’ statewide rule that permits an ADU on any single-family lot. Boston has been ahead of most cities with its own ADU program that makes it much easier for homeowners to create internal, attached, or detached ADUs in most of their neighborhoods. Your unit just needs to meet the state size limit of up to 900 sq. ft. or 50% of your main home’s floor area. Boston will review it through the standard building and zoning process.
The city may still check things like design, parking adjustments, and utility capacity, but it cannot ban ADUs outright under the new state law. Overall, Boston is one of the most ADU-friendly municipalities in Massachusetts, giving homeowners a clear path to add rental space, family housing, or a backyard cottage.
To initiate the ADU approval process, please contact the Planning Department.
Does Worcester Allow ADUs?
Yes, Worcester allows ADUs, and the city has already updated its zoning to align with Massachusetts’ statewide by-right ADU law. Homeowners in Worcester can build an internal, attached, or detached ADU as long as it fits the state size limit of up to 900 sq. ft. or 50% of the main home’s floor area.
Worcester also has clear local guidelines that cover basics like setbacks, separate entrances, utility hookups, and building-code compliance, but none of these rules prevent you from adding an ADU. Because Worcester was an early adopter of ADU-friendly zoning, the permitting process is straightforward, making it one of the easiest cities in the state for adding a rental unit, in-law suite, or small backyard cottage.
Still, it’s essential to confirm compliance with all relevant ADU requirements, so be sure to contact Planning and Regulatory Services.
Does Springfield Allow ADUs?
Yes, Springfield allows ADUs, and the city follows Massachusetts’ statewide rule that permits one ADU by right on any single-family lot. Springfield’s zoning framework focuses on keeping ADUs safe, code-compliant, and clearly secondary to the main house, which means most homeowners can add an attached, internal, or detached ADU without major hurdles.
The city typically requires compliance with standard setbacks, a permanent foundation, and full building-code standards for kitchens, bathrooms, insulation, and egress. With the new statewide ADU law now in effect, Springfield has one of the more predictable and accessible approval processes, making it easier for residents to build in-law suites, rental units, and backyard cottages that expand housing options across the city.
Of course, it’s still best to check with the city’s Planning and Economic Development Department to ensure compliance.
Does Cambridge Allow ADUs?
Yes, Cambridge absolutely allows ADUs, and it’s one of the most ADU-friendly cities in Massachusetts. Cambridge was an early adopter of flexible accessory housing rules, allowing homeowners to create accessory apartments inside, attached to, or detached from their primary home. Under the statewide 2025 ADU law, the city now permits one ADU by right on any single-family zoned lot, as long as it meets standard safety and building-code requirements.
Cambridge’s approach focuses on safe construction, proper egress, and maintaining the ADU as a secondary unit, but the city does not impose heavy restrictions on appearance, owner occupancy, or extra parking. This makes adding an ADU far more accessible than in many other municipalities. For homeowners in Cambridge, the ADU approval process is now clearer, faster, and easier, helping support both affordability and multi-generational living.
Please ensure you check with the Planning and Urban Design Department before commencing construction to confirm compliance with their requirements.
Does Lowell Allow ADUs?
Yes, Lowell allows ADUs, and the city follows Massachusetts’ statewide rule permitting one ADU by right on any single-family residential lot. This means most homeowners can build an attached, interior, or detached ADU without needing a special permit, as long as the unit meets standard setbacks, building codes, and safety requirements. Lowell’s local zoning focuses on ensuring ADUs remain clearly secondary to the main home, but the city does not add restrictive rules like owner-occupancy requirements or excessive parking mandates.
For residents of Lowell, this creates a straightforward path to adding in-law suites, rental units, or backyard cottages, all while supporting the city’s broader goals of increasing housing flexibility and affordability. Be sure to contact the Planning and Development Department to ensure compliance.
Does Brockton Allow ADUs?
Yes, Brockton allows ADUs, and the city follows Massachusetts’ statewide law that permits one ADU by right on any single-family lot. This makes it much easier for homeowners to add a basement apartment, garage conversion, or detached backyard cottage without going through a burdensome special-permit process. Brockton’s local regulations mainly focus on life-safety standards, setbacks, height limits, and full building-code compliance, ensuring the ADU is safe and clearly secondary to the main home.
Because Brockton does not add extra restrictions like owner-occupancy rules, parking mandates, or architectural-matching requirements beyond normal zoning, most residents can move forward with an ADU as long as the design fits their lot and meets residential code. This streamlined approval process makes Brockton one of the more accessible places in the region for adding in-law suites, rental units, and multi-generational housing.
To confirm compliance with the city’s regulations, contact the Department of Planning and Economic Development.
Does Quincy Allow ADUs?
Yes, Quincy allows ADUs, and the city follows Massachusetts’ statewide rule that lets homeowners build one Accessory Dwelling Unit (ADU) by right on any single-family lot. This makes it much easier to add an in-law suite, basement apartment, or backyard cottage without navigating a long special-permit process. Quincy’s ADU rules are straightforward: the unit must remain smaller than the main home, meet standard zoning setbacks, and follow full residential building-code requirements for things like safety, egress, utilities, and foundation.
The city also doesn’t pile on extra restrictions, so there are no additional parking mandates, no owner-occupancy rules, and no strict architectural-matching requirements beyond what already applies to a normal house. For homeowners in Quincy, that means a smooth, predictable path to adding flexible housing that supports family, rental income, or long-term property value. To get started, simply contact the Planning and Community Development Department.
Does Lynn Allow ADUs?
Yes, Lynn allows ADUs, and the city follows Massachusetts’ statewide rule that lets homeowners build one Accessory Dwelling Unit (ADU) by right on any single-family property. This gives residents a clear, straightforward path to adding an in-law suite, basement apartment, or backyard cottage without needing a special permit. Lynn’s requirements focus on the basics: the ADU must remain smaller than the main home, fit within existing setback and height limits, and meet all standard building-code rules for safety, utilities, and foundation.
The city doesn’t impose extra hurdles, such as owner-occupancy mandates, strict architectural matching, or additional parking requirements. Overall, Lynn offers a smooth and predictable ADU approval process, making it an excellent option for homeowners seeking flexible space, rental potential, or multigenerational living arrangements. Still, it’s essential to verify requirements with the Planning Department.
Does New Bedford Allow ADUs?
Yes, New Bedford allows ADUs, and like other Massachusetts municipalities, the city follows the statewide rule that permits one Accessory Dwelling Unit (ADU) by right on any single-family lot. This means homeowners can add an in-law suite, finished basement apartment, garage conversion, or small detached unit without going through a complicated special-permit process. New Bedford’s requirements are mainly focused on safety and zoning basics: the ADU must be smaller than the primary home, stay within standard setback and height limits, and meet all residential building-code standards for things like egress, structural safety, electrical, and plumbing.
The city does not add extra restrictions like mandatory owner-occupancy, additional parking requirements, or strict design-matching rules. For New Bedford residents, this creates a smooth and accessible path to adding extra living space, supporting multigenerational families, or generating long-term rental income. Ensure compliance with all applicable ADU regulations by contacting the Planning Department.
Does Somerville Allow ADUs?
Yes, Somerville allows ADUs, and it’s actually one of the most ADU-friendly cities in Massachusetts. After updating its zoning code, Somerville now permits homeowners to build an ADU by right, meaning most projects no longer require lengthy hearings or special approvals. The city allows ADUs up to 900 sq. ft. or 50% of the primary home, whichever is smaller, and no longer enforces owner-occupancy rules or extra parking requirements for properties located near public transit.
As long as the unit fits within standard setback, height, and building-code requirements, homeowners can add basement apartments, garage conversions, or backyard cottages with a much faster, more predictable approval process. This makes Somerville one of the easiest places in the state to add flexible housing, support multigenerational living, or create long-term rental potential.
To ensure you meet these requirements, please contact the Planning, Preservation, and Zoning Department.
Does Newton Allow ADUs?
Yes, Newton allows ADUs, and the city has some of the clearest and most established ADU rules in Massachusetts. Newton permits one Accessory Dwelling Unit by right on any single-family property, making it easy for homeowners to add an in-law suite, basement apartment, or backyard cottage without needing a special permit. The city requires the ADU to remain smaller than the primary home, comply with standard zoning setbacks, and meet full residential building-code standards for utilities, safety, and egress.
Newton previously had tighter restrictions, but updated its zoning to simplify approvals and remove unnecessary barriers. Today, Newton offers one of the smoothest ADU pathways in the region, giving homeowners a reliable way to create additional living space, support multigenerational families, or generate rental income. Contact the Planning and Development Department to get the process started.
Does Fall River Allow ADUs?
Yes, Fall River allows ADUs, and the city follows Massachusetts’ statewide rule that permits one Accessory Dwelling Unit (ADU) by right on any single-family lot. This gives homeowners a simple, predictable path to adding an in-law suite, basement apartment, garage conversion, or small detached unit without needing a special permit. Fall River’s requirements focus on the essentials: the ADU must be smaller than the primary home, fit within existing setback and height rules, and meet all state building-code standards for safety, utilities, and proper egress.
The city does not add extra hurdles like owner-occupancy mandates, strict architectural matching, or additional parking rules beyond what already applies to a normal home. Overall, Fall River provides an easy, homeowner-friendly environment for building ADUs which is ideal for multigenerational living, extra space, or long-term rental income.
Still, it’s essential to double-check the requirements for your ADU with the Planning Department.
Does Framingham Allow ADUs?
Yes, Framingham allows ADUs, and the city now follows Massachusetts’ statewide rule that permits one Accessory Dwelling Unit (ADU) by right on any single-family property. This means homeowners can add an attached, interior, or detached ADU without going through a special permit process, as long as the unit meets the basic state requirements. In Framingham, an ADU must remain smaller than the main home, fit within standard setback and height limits, and comply with all building-code rules for safety, egress, utilities, and structural design.
The city does not impose extra hurdles like owner-occupancy mandates, architectural-matching requirements, or additional parking rules beyond what already applies to a typical residence. With these clear and consistent standards, Framingham offers a smooth, predictable pathway for building in-law suites, rental units, or backyard cottages.
Be sure to confirm compliance with all applicable rules with the Planning Department before embarking on your ADU project.
Does Waltham Allow ADUs?
Yes, Waltham allows ADUs, and the city follows Massachusetts’ statewide rule that permits one Accessory Dwelling Unit (ADU) by right on any single-family lot. That means most homeowners can add a basement apartment, in-law suite, or small backyard cottage without going through a lengthy special-permit process. Waltham’s requirements focus on the basics: the ADU must stay smaller than the primary home, meet standard setback and height limits, and comply with full state residential building-code standards for safety, utilities, and egress.
The city does not add extra barriers such as owner-occupancy rules, strict architectural matching, or additional parking mandates. Overall, Waltham offers a clear, predictable, and homeowner-friendly pathway for adding flexible living space, multigenerational housing, or long-term rental potential. Contact the Planning Department to get started.
Does Lawrence Allow ADUs?
Yes, Lawrence allows ADUs, and the city follows Massachusetts’ statewide rule that permits one Accessory Dwelling Unit (ADU) by right on any single-family lot. This means homeowners can build an ADU without needing a special permit, as long as the project meets the state’s core requirements. In Lawrence, your ADU must remain smaller than the main home, fit within standard setback and height limits, and comply with all state building-code standards for safety, fire protection, utilities, and egress.
The city doesn’t impose extra hurdles, such as owner-occupancy rules, strict architectural matching, or additional parking mandates. Overall, Lawrence offers a straightforward approach to incorporating multigenerational housing, rental space, or an extra room for the family. Even so, it’s essential to check that all requirements are met with the Planning Department.
Searching for an ADU Builder Serving Massachusetts?
The best part about understanding Massachusetts’ ADU rules is that you’re now ready for the fun part: finding the right builder to bring your ADU to life. Zook Cabins delivers anywhere in Massachusetts, from the Berkshires to Cape Cod, making it easy to get a high-quality ADU no matter where you live. With years of hands-on experience, modern building methods, and a deep passion for flexible living spaces, our team is built to guide you every step of the way. Want to explore your options? Reach out to speak with a sales expert or request a free quote today. You’ll get clear pricing, exceptional craftsmanship, and dedicated support from your first question to move-in day.
Tiny Homes & ADU Rules by State: How Do They Compare?
Massachusetts stands out from many other states because it now has one of the clearest, most homeowner-friendly ADU laws in the country. While states like California and Oregon are well-known for strong ADU protections, Massachusetts has joined that group with a statewide rule allowing one ADU by right on any single-family lot, giving residents a consistent, predictable path across nearly every city and town.
Compared to states where ADU rules vary wildly from county to county, Massachusetts offers a unified baseline: ADUs can be up to 900 sq. ft. or 50% of the main home, must meet standard residential building code, and can be built as attached, interior, or detached units—no special permit required in most cases. Tiny homes follow a similar pattern: foundation-built tiny homes count as ADUs, but tiny homes on wheels are treated as RVs and cannot serve as permanent dwellings. To help you compare states easily, we provide clear, state-by-state guides for both tiny home regulations and ADU rules, so you always know exactly what’s allowed wherever you plan to build.
In short, if you’re comparing states, Massachusetts ranks among the easiest and most reliable places to build an ADU on the East Coast. Clear rules, statewide consistency, and modern housing policies make MA a top choice for anyone looking to add flexible space, support multigenerational living, or build a small, code-compliant backyard home.
Conclusion…
Massachusetts stands in a different league when it comes to ADU rules. Instead of the patchwork regulations you see in other states, MA gives homeowners a clear, statewide path that actually makes building an ADU feel doable. Whether you’re planning a cozy in-law suite or a modern backyard cottage, the rules here make the process far more predictable than most places in the country. And when you’re ready to turn those plans into something real, Zook Cabins is here to guide you through every step.
From choosing the right design to understanding what works on your property, we’re ready to help you build an ADU that elevates the way you live. Reach out whenever you’re ready, we’d love to help you Dwell Beyond The Ordinary.