Accessory dwelling units were legalized statewide almost nine months ago. However, obtaining a building permit is not a straightforward process. According to state housing officials, 550 ADUs were approved statewide in the first half of 2025.
Despite the legalization, builders and experts say that the process of permitting and financing new units is complex. Rapid, modular construction techniques are being used in the ADU sector, and hundreds of homeowners are taking advantage of the opportunity.
“Zoning is one of the 10 horsemen that approve your building in Massachusetts, and the other nine are still there,”
said Chris Lee, head of design and development at Backyard ADUs. Financial hurdles remain, preventing some property owners from entering the market.
Author's summary: Building ADUs remains costly despite legalization.