Massachusetts ADUs ‘By Right’
Massachusetts' Affordable Homes Act tool effect in February 2025, making it easier for homeowners to build Accessory Dwelling Units (ADUs). ADUs are small, separate living spaces on the same property as a main house, often called "in-law apartments" or "backyard cottages." They help create more affordable and flexible housing options for families, seniors, students, and individuals looking for convenient and sustainable living arrangements.
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Here's what you need to know about the current ADU rules in Massachusetts:
ADUs can be up to 900 square feet or half the size of the main home, whichever is smaller. This size is ideal for creating comfortable living spaces that don’t overwhelm the main property.
Homeowners can rent out both the main home and the ADU. You don’t have to live in either one, giving you greater flexibility and income opportunities.
You no longer need special permits for standard ADUs that follow state rules, making the building process quicker and more affordable.
Cities can't require extra parking spaces if the ADU is within half a mile of public transportation, encouraging environmentally friendly commuting options and reducing reliance on cars.
Towns can still set their own reasonable rules about things like septic systems, distances from property lines, and short-term rentals, ensuring communities can address local concerns while supporting new ADUs.
Municipalities are required to update local zoning to align with these state regulations, further simplifying the approval process for homeowners.
These changes aim to help with the state's housing shortage by promoting affordable, efficient, and eco-friendly building practices. The Massachusetts state government estimates that these rules could create 8,000-10,000 new homes in the next five years, significantly helping to ease the state's current housing challenges.
Why Pick Rare Forms ADU Kits?
At Rare Forms, we build ready-to-assemble ADU kits designed specifically to meet these new state regulations. Our ADUs use sustainable, environmentally friendly materials and construction methods, making them an excellent choice for Massachusetts homeowners who value ecological responsibility.
Rare Forms: ADU under construction
Our models—including the Acorn, Chestnut, and Casita Series—feature:
Practical designs up to 900 square feet that maximize available space without sacrificing comfort or functionality
Easy-to-access floor plans featuring first-floor bedrooms, open living spaces, and flexible areas perfect for a variety of lifestyles and accessibility needs
High-quality insulation made from compressed straw, providing exceptional thermal performance and energy efficiency
Moisture control systems that are airtight yet vapor-open, allowing buildings to effectively manage moisture and dry out if water ever enters the walls or roof
Durable, naturally pest-resistant and fire-resistant materials that ensure long-term safety and minimal maintenance needs
Customizable interior options to suit individual preferences and lifestyle requirements
Because our kits are prefabricated offsite, they significantly reduce construction time and costs. Typically, building high-performance homes in Massachusetts costs between $500-$650 per square foot. In contrast, our ADU kits are priced between $350-$500 per square foot, making high-quality, eco-friendly housing more accessible to a wider range of homeowners.
Rare Forms ADUs also offer meaningful environmental benefits by using renewable, carbon-capturing materials. Our buildings actively help fight climate change by storing carbon in their construction materials, making them not just sustainable but regenerative.
Our designs put a strong focus on comfort, health, and sustainability. By prioritizing natural, non-toxic materials, we create safe, healthy homes with excellent indoor air quality. This approach contributes positively to occupants' long-term health and well-being.
Massachusetts' new ADU regulations provide homeowners a valuable opportunity to expand their properties sustainably and economically. Rare Forms is here to help you take advantage of this opportunity with intelligently designed, affordable, and environmentally responsible homes that align with your personal values and state guidelines.
