What Homebuyers Should Know About Accessory Dwelling Units (ADUs) in Massachusetts and Rhode Island
- southcoasteventman
- 1 day ago
- 4 min read
Accessory Dwelling Units (ADUs) are increasingly popular—and for good reason. Whether you’re a Massachusetts homebuyer or one looking in Rhode Island, understanding ADUs can help you see value, flexibility, and long-term potential in a property. Let’s dive into what ADUs are, how the laws are evolving, and how they affect homebuyers in both states.
What is an Accessory Dwelling Unit (ADU)?
An accessory dwelling unit (ADU) is a secondary living space on the same property as a primary residence. You’ll also hear them called in-law apartments, accessory apartments, guest houses, or backyard cottages. Common forms include:
Internal ADUs: A basement conversion, attic apartment, or within the existing home.
Attached ADUs: An addition onto the home, or a unit above the garage.
Detached ADUs: A free-standing dwelling on the same lot, often a “tiny house” or separate cottage.
They’ve been around in various forms for a long time (servants’ quarters, mother-in-law houses) but high housing costs and changing lifestyles have renewed interest in ADUs.
Why Append “Massachusetts and Rhode Island” to the Conversation?
If you’re searching for homes or planning investment in New England, the states of Massachusetts and Rhode Island are worth comparing for ADU regulations and opportunities. Conditions differ, and knowing both will make you a smarter homebuyer.
ADU's in Massachusetts: What Homebuyers Should Know
In Massachusetts, ADU rules have recently become more flexible, making them a stronger consideration for homebuyers.
Key Highlights for Massachusetts
A major legislative development: In August 2024, Massachusetts Governor Maura Healey signed a housing bond bill (approx. $5.16 billion) that allows ADUs by right in many single-family zones statewide. These can include basement/attic apartments, home additions, or detached small dwellings.
What this means: Homeowners and future homebuyers in Massachusetts can more easily consider properties with existing or potential ADUs.
Types of ADUs covered: Internal, attached, and detached units.
Benefits:
For homeowners: Additional revenue stream (renting the ADU) or added space for family/office/gym/homeschool.
For homebuyers: Choose a home that already offers an ADU or future ADU option, increasing flexibility.
For communities: More housing density, better use of land, more affordable options.
Regulatory Considerations in Massachusetts
Even with the new law, local zoning and building regulations still apply (size limits, number of bedrooms, parking, lot size).
Homebuyers should verify: existing ADU units were properly permitted; proposed ADUs will comply with municipal bylaws.
ADUs cannot usually be sold separately from the main home (they’re part of the same property).
Make sure systems (septic, utilities) support the ADU if detached or new construction is planned.
Why It Matters for Homebuyers in Massachusetts
If you buy a property with an ADU, you might immediately benefit from rental income or use the space for family.
If you buy a property with potential for an ADU, you’re buying option value. That increases resale attractiveness.
ADUs support multi-generational living — a young adult who wants independence, aging parents who want proximity, and so on.
ADU's in Rhode Island: A Rising Opportunity for Homebuyers
Rhode Island has also moved to make ADUs more accessible — a strong consideration for any homebuyer in the state or exploring in-state investment.
Key Highlights for Rhode Island
A new law was signed in June 2024 (legislation 2024-H 7062A / 2024-S 2998A) that gives homeowners in Rhode Island the right to develop a single ADU on an owner-occupied property under certain criteria. Rhode Island General Assembly+1
Under Rhode Island law:
A one-bedroom ADU may be up to 900 sq ft or 60% of the main dwelling’s area (whichever is less). AARP States+2Zook Cabins+2
A two-bedroom ADU may be up to 1,200 sq ft or 60% of the main dwelling’s area. AARP States+2Zook Cabins+2
The law prohibits using the ADU as a short-term rental (i.e., tourist/hosting platform) in many cases. City of Providence+1
ADUs can be interior, attached or detached units — though local zoning may impose additional restrictions. HousingWorks RI+1
Regulatory Considerations in Rhode Island
Municipalities still enforce local zoning (setbacks, height, lot size) even though the state has set minimums. Zook Cabins+1
Some municipalities require the lot to be at least 20,000 sq ft for detached ADUs outside the home‐footprint. Warwick RI+1
At the homebuyer stage, you should check:
Whether the property is owner-occupied or whether the owner occupancy requirement applies.
Whether the ADU was properly permitted or if you’re planning to convert an existing structure.
If the local municipality allows detached units or requires connection to sewer/water.
Why It Matters for Homebuyers in Rhode Island
You can select a home that already has an ADU or has space for one — increasing future flexibility or income potential.
If you’re buying with the idea of housing family members (e.g., aging parents, young adult children) or generating rental income, ADUs offer a strategic pathway.
Given the new law, ADUs may also boost the resale value of the property by appealing to a broader market (multigenerational buyers, investors, “live-work” buyers).
Tips for Homebuyers Considering a Property With (or For) an ADU
Ask whether there’s an existing ADU or strong potential for one (in Massachusetts or Rhode Island).
Check the permits: For an existing ADU, confirm building and zoning permits were obtained and inspections passed.
Check local zoning rules: Especially for detached ADUs or lots with unusual size/shape.
Check utility infrastructure: Especially if you plan a detached unit — is there proper sewage/water or will upgrades be necessary?
Check rental rules: If income is a goal, make sure ADU use is allowed as a long-term rental (not merely short-term).
Think resale value: A home with an ADU or potential for one may appeal to a wider set of buyers (multigenerational families, investors, remote workers).
Work with professionals: Real estate agents familiar with ADUs, builders/architects who've done the work, and local zoning consultants will all help.
Budget realistically: Whether converting an attic or building a detached cottage, costs vary. But the upside is flexibility and potential for rental income.
Final Thoughts
For Massachusetts homebuyers, the evolving ADU landscape means increased opportunity and choice. For Rhode Island buyers, recent legislation opens up fresh avenues for value and flexibility. In both states, ADUs represent a compelling way to invest in a home that’s versatile, future-focused, and aligned with changing family and housing dynamics.