Accessory Dwelling Units
WHAT IS AN ADU?
An Accessory Dwelling Unit (ADU) is a small, independent living space located on the same property as an existing home. ADUs are an important tool in addressing the housing crisis. Under a recent policy signed by the MA Governor, homeowners can now construct an ADU without requiring special or discretionary approval from the local zoning board.
ADUs can take various forms, such as being incorporated within an existing home by converting a basement into an apartment, added as a new construction attachment to the primary residence, or built as a standalone structure like a backyard cottage or a converted detached garage.
The Affordable Homes Act updates the definition of “Accessory Dwelling Unit” in Section 1A of Chapter 40A of the MA General Laws. It specifies that an ADU must be no larger than 900 square feet or half the size of the principal dwelling, whichever is smaller. The changes also eliminate owner-occupancy requirements and prohibit unreasonable restrictions on the creation or rental of ADUs.
BENEFITS OF INVESTING IN AN ADU FOR YOUR PROPERTY
✓ Permitted and built swiftly, addressing the urgent housing crisis within months.
✓ Require year-round leases, ensuring they aren’t used as short-term rentals.
✓ Designed within existing wastewater limits and with minimal tree clearing.
✓ Maximize the functionality of single-family homes.
✓ Blends seamlessly into neighborhood settings.
✓ Add value to your property.
✓ Offer homeowners an opportunity to generate income from their largest asset.
✓ Built without requiring significant public funding.
✓ Provide adaptable living options as homeowners’ needs change over time.
WHAT ARE MA REQUIREMENTS FOR AN ADU?
✓ Must have a separate entrance (directly outside or through a shared corridor that meets state building code).
✓ Can be no larger than 50% of the main home’s floor area or 900 sq. ft., whichever is smaller.
✓ Designed within existing wastewater limits and with minimal tree clearing.
✓ Must comply with local municipal restrictions, which may include size limits or bans on short-term rentals.
✓ The number of bedrooms in an ADU is limited to two
✓ An ADU can only be used as a rental, except that the owner of the property can live in the ADU while renting the principal dwelling.
✓ Rentals of any duration less than 12 months are not permitted, including short term rentals (of the principal dwelling or ADU).