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Accessory Dwelling Units (ADU’s)

Accessory Dwelling Unit Types

An Accessory Dwelling Unit is a secondary residential living space located on the same lot of a single-family home. ADUs can play a significant role in our housing crisis. The ADU policy recently signed by the governor allows property owners to build an ADU without having to get special or discretionary approval from the local zoning board.

ADUs can be within an existing primary residence, like converting a basement into an apartment, attached to a primary residence as a new construction addition, or completely detached, like a cottage or converted detached garage in a backyard.

The Affordable Homes Act amends the definition of “Accessory Dwelling Unit” under Section 1A of Chapter 40A of the General Laws to clarify that the maximum size of an ADU is no more than half of the gross floor area of the principal dwelling, or 900 square feet, whichever is smaller. The definition was also amended to prohibit owner-occupancy requirements and unreasonably restricting the creation or rental of an ADU that is not being used as a short-term rental, as that term is defined in room occupancy excise laws (Section 1 of Chapter 64G of the General Laws). 

Visit Mass.gov Accessory Dwelling Units (ADU’s) for more information.

After Sunday, February 2, 2025, zoning provisions that are inconsistent with MGL c. 40A Section 3 may be unenforceable. An application for an ADU in a single-family zoning district that is consistent with MGL 40A definition and requirements should be accepted and acted on consistent with state statute.

The Town of Nahant will be considering an article to amend local zoning by-laws at Annual Town Meeting in May 2025. However, like most municipalities in the Commonwealth, the Town of Nahant will need the Commonwealth to finalize their regulations prior to drafting a zoning by-law article.

EOHLC released their draft regulations on December 6, 2024 with a comment period starting December 20, 2024 and ending January 10, 2025.

ADU Draft Regulation 760 CMR 71

Letter from Secretary Augustus

EOHLC Webinar, November 4, 2024

To comment on the draft regulations, you must complete an online form and submit to EOHLC