In Massachusetts, Accessory Dwelling Units (ADUs), often referred to as "in-law apartments" or "granny flats," have gained prominence as a flexible housing solution. They offer homeowners the potential to create additional living space while boosting property value and contributing to housing affordability.
Read on to learn the concept of ADUs, their legal status in Massachusetts, associated costs, and how they can benefit both homeowners and communities.
What is an ADU?
An Accessory Dwelling Unit, or ADU, is essentially a "house within a house" – a fully independent living space situated on the same property as a larger, primary residence. To qualify as an ADU, it must be self-contained, meaning it has its own kitchen, bathroom, and sleeping area, distinguishing it from simply adding an extra room to the existing house.
It also must be located on the same lot as the single-family home. ADUs can take various forms, either attached to the primary dwelling, such as a converted basement or attic, or detached, like a backyard cottage or a converted garage. This mini-apartment setup offers flexibility for multigenerational living, rental income, guest accommodations, or a dedicated workspace.
Are Accessory Dwelling Units Legal in MA?
Yes, ADUs are legal in Massachusetts, thanks to recent legislation that aims to promote housing diversity and affordability. The state has relaxed zoning laws to allow for more ADU construction, but certain local regulations and restrictions still apply.
What is the Accessory Dwelling Unit Bill in Massachusetts?
The Accessory Dwelling Unit Bill, signed into law in August 2023, significantly expanded the possibilities for ADUs in Massachusetts. It streamlines the permitting process, eases zoning restrictions, and provides homeowners with more flexibility to create ADUs on their property.
State-Level Regulations (As of August 2023)
By-Right ADUs in Single-Family Zones:
The new law makes it easier to build an ADU in most single-family zoning districts statewide. You can now construct one ADU "by-right," meaning you don't need any special permit or approval from local zoning boards. This streamlines the process and reduces potential barriers.
Size Limits:
Interior ADUs:
For ADUs within your existing house, the maximum size is capped at 1,000 square feet, or 50% of the main house's living area – whichever is smaller.
Detached ADUs:
Standalone ADUs built on your lot have a maximum size of 900 square feet, or 50% of the main house's living area – again, whichever is smaller
Learn more:
How to Measure Square Footage of a House Like a Pro
Height Limits:
Detached ADUs can't exceed 2.5 stories or 35 feet in height, ensuring they blend well with the surrounding neighborhood.
Setbacks:
ADUs must adhere to local setback rules, which dictate how far the structure must be from property lines and other buildings. These vary by town or city, so it's important to check your local zoning.
Parking:
Interior ADUs: No additional off-street parking is mandated by the state law.
Detached ADUs: One off-street parking space is generally required, unless waived by your local zoning board.
Owner-Occupancy:
In most cases, either the main house or the ADU must be owner-occupied. This encourages ADUs to be used for family members or long-term rentals, promoting stable communities. However, your local zoning board can waive this requirement.
Short-Term Rentals:
Short-term rentals of ADUs (think Airbnb) are generally allowed, but your town or city may have additional rules or restrictions regarding this use.
Local Regulations: Navigating Town-Specific Rules
While the state law provides a framework, municipalities retain the right to create additional regulations regarding ADUs. These local rules can include:
Stricter Size or Height Limits: Some towns might impose stricter size or height limitations than the state-mandated ones.
Design Guidelines: Some municipalities may have architectural or design guidelines to ensure ADUs complement the existing neighborhood aesthetic.
Additional Parking Requirements: Even for interior ADUs, local ordinances may mandate more than the state's minimum parking requirements.
Owner-Occupancy Variations: Some towns might have stricter owner-occupancy rules than the state, possibly limiting your rental options.
Impact Fees: Some localities may charge impact fees to help cover the added strain on infrastructure and services.
Benefits of ADUs for Homeowners:
Increased Property Value: An ADU can be a significant value-add to your home, potentially increasing its market appeal and resale price. It's like adding a mini-income property to your lot.
Rental Income: Generate extra cash flow by renting out your ADU. This can help offset mortgage payments, cover property taxes, or even provide a source of passive income.
Multigenerational Living: ADUs create opportunities for multigenerational families to live together while maintaining privacy and independence. They can be ideal for aging parents, adult children returning home, or other family members.
Housing Affordability: ADUs contribute to increasing the overall housing supply, creating more affordable options for individuals and families in areas with high housing costs.
Potential Drawbacks of ADUs:
Upfront Costs: Building or converting an ADU requires a financial investment. Costs can include design, permits, construction materials, and labor.
Zoning and Permitting: While the new Massachusetts ADU law streamlines the process, you still need to navigate local zoning regulations and permitting requirements.
Privacy Concerns: Sharing your property with another household may impact your privacy. Careful planning and design can help mitigate this concern.
Parking and Traffic: Depending on your neighborhood and local regulations, you may need to address parking and traffic considerations, especially for detached ADUs.
Key Considerations for Homeowners in Massachusetts:
Consult Local Zoning: Always start by contacting your local zoning board or building department to fully understand the specific ADU regulations in your community.
Professional Expertise is Key: Enlist the help of an architect, builder, and a real estate attorney to ensure your project meets all regulations and is executed smoothly.
Plan Your Budget: ADUs are a significant investment. Account for all costs, including design, materials, labor, permits, and any potential impact fees.
Understand Rental Rules: If your goal is to generate rental income, research local landlord-tenant laws and any restrictions on short-term rentals.
How Much Does an ADU Cost in Massachusetts?
The cost of constructing an ADU in Massachusetts isn't a one-size-fits-all figure; it's influenced by various factors that contribute to the overall project expenses. Naturally, the size and design of the ADU play a significant role. Larger units with more elaborate designs and high-end finishes will naturally cost more than smaller, simpler ones.
Location also plays a part, as construction costs can fluctuate based on your region and the local labor market. You may find that materials and labor are more expensive in certain areas, impacting your overall budget.
The type of ADU you choose also influences the cost. Converting an existing space, such as a basement or garage, is often a more budget-friendly option compared to building a new detached structure from the ground up. This is because you're already working with an existing foundation and some utilities may be readily available.
Don't forget to account for permits and fees. Obtaining the necessary permits from your local government will add to the cost, and some municipalities may also impose impact fees to cover the strain on infrastructure or services.
On average, you can expect to pay anywhere from $150,000 to $300,000 or more to build a new detached ADU in Massachusetts. However, converting an existing space might be a more economical route, with costs starting around $50,000.
The best way to get an accurate estimate for your specific project is to obtain quotes from several reputable contractors. This allows you to compare prices, understand the scope of work involved, and choose a contractor who fits your budget and project requirements.
What Towns in MA Allow ADUs?
While ADUs are generally allowed throughout Massachusetts, specific regulations and zoning requirements vary by town or city.
Some municipalities have more permissive regulations, while others may have restrictions on size, location, or rental potential. It's essential to consult with your local zoning board or building department to understand the specific regulations in your area.
The Bottom Line
ADUs are an increasingly popular housing solution in Massachusetts, offering a range of benefits for homeowners and communities alike. Whether you're looking to generate rental income, accommodate family members, or increase your property value, an ADU might be the right choice for you.
If you're considering building an ADU, be sure to research your local zoning laws, obtain necessary permits, and work with qualified professionals to ensure a successful project. Home Shift Team is here to help you with information and resources related to ADUs and other real estate matters.
