Acton warrant article would revise zoning to expand accessory dwelling units under state law

Article 30, placed on the warrant for a Town Meeting vote, would amend the Town of Acton zoning bylaw to replace the term “accessory apartment” with “accessory dwelling unit” and establish new standards for accessory dwelling units (ADUs). The article, which according to the warrant requires a two-thirds majority vote to pass, is presented as a local implementation of the state Affordable Homes Act and associated state regulations for ADUs.

The article would permit no more than one accessory dwelling unit per lot. It sets a maximum gross floor area for an ADU at less than 50% of the principal unit’s gross floor area or 900 square feet, whichever is smaller. A separate provision would allow ADUs located within basement areas of an existing principal dwelling that have been in continuous use before 05/06/2025 to have no maximum gross floor area.

For detached buildings, the article would allow an ADU in a detached structure that existed on the lot before April 2019 to have a gross floor area up to 2,000 square feet, excluding attic and basement areas and not including interior garage or parking spaces, provided the building’s footprint and floor area are not expanded after that date. The article would require that any ADU in a detached building be constructed on a permanent foundation and that lots containing a principal unit and an ADU in a detached building not be subdivided in a way that separates the units unless both resulting lots and the buildings on them meet all minimum area, frontage, width and yard requirements of the applicable zoning district.

Parking requirements in the proposed bylaw would be relaxed in some respects but impose an added requirement in others: an ADU located on a lot outside a 0.5-mile radius of a transit station would require one additional dedicated parking space for the ADU resident. The article also maintains that no ADU may be constructed or occupied without building and occupancy permits issued by the building commissioner.

The warrant explanation says the changes are intended to align Acton’s zoning with the Affordable Homes Act and state ADU regulations, to remove local barriers such as certain design, parking and owner-occupancy requirements, and to expand housing options for caregivers, residents aging in place and families. The Town’s Select Board unanimously voted to recommend Article 30, according to the meeting record; the transcript does not record a Town Meeting vote on the article.

The article would also include a townwide textual change replacing the phrase “accessory apartment” with “accessory dwelling unit” wherever it appears in the zoning bylaw. The transcript and warrant materials provided do not specify the date of the Town Meeting vote or the vote outcome on Article 30.