What Massachusetts Homeowners (and Boards) Need to Know in 2026

Accessory Dwelling Units (ADUs) are having a moment, and for good reason. Whether you call it an “in-law,” a backyard cottage, a garage conversion, or a basement apartment, an ADU is typically a self-contained secondary housing unit on the same lot as a primary home, with its own cooking, sleeping, and bathroom facilities. But before you start sketching layouts, there’s one key reality: ADU rules are highly local , and “allowed” doesn’t always mean “simple.” Below is a practical, up-to-date guide to the most common regulations you’ll run into (with New England-specific notes), plus the strongest reasons homeowners are choosing to build ADUs in 2026.

Condo boards and property managers across New England are seeing a big uptick in requests to install solar rooftop. The friction usually isn’t about “solar” itself—it’s about who controls the roof, how common areas are altered, liability/insurance, and whether the association can say “no.”  Below is a practical, board-friendly overview of the most relevant “new” and newly emphasized legal guidance in Massachusetts (plus important Rhode Island notes), and how CSL (Construction Supervisor License) regulations fit into the approval and permitting process.