City Council committee approves amendment to city’s rules for ADUs

Waltham City Council’s Ordinance and Rules Committee on Monday voted 2-1 to approve an amendment to the city’s accessory dwelling units (ADU) ordinance. 

Ward 3 Councilor Bill Hanley introduced the amendment, which changes the minimum unit size from 300 square feet to 450 square feet. He said the increase would make the units feel less like dorms and more like homes.

That increased size will impact the number of ADUs that could be built in the city, said Ward 9 Councilor Robert G. Logan. 

He said increasing the minimum square footage of the ADUs reduces the number of houses eligible to build an ADU on their lots by 160. The state’s Affordable Homes Act states that ADUs cannot exceed 900 square feet or 50% of the “principal dwelling unit.” As a result, eligible Waltham principal dwelling units will need to be at least 900 square feet, as opposed to 600 square feet.

City Solicitor Katherine D. Laughman said the amendment could become an issue if “it makes it difficult for people to take advantage of the protected use of ADU opportunities.”

However, she said owners of ineligible homes have a recourse: They can seek permission to build ADUs from the Zoning Board of Appeals and the court system, if needed.

ADUs became permitted by right in Massachusetts earlier this year as part of the Affordable Homes Act. ADUs “are small, independent living spaces located on the same lot as a principal dwelling in a single-family residential zoning district.” They are often stand-alone structures or converted basements and attics. 

Councilors who voted to approve the amendment were Council President John J. McLaughlin and Hanley. Logan voted against the amendment. Ward 8 Councilor Cathyann Harris did not vote, and Ward 2 Councilor Caren Dunn was not present.

Following the Ordinance and Rules Committee approval, the amended ADU ordinance will go back to the City Council for a first reading – part of the legislative process to enact the proposed ADU rules into law.