Planning board keeps ADU hearing open as counsel clarifies preexisting nonconforming, condo and garage questions

The Southborough Planning Board on Feb. 10 continued its public hearing on a proposed accessory dwelling unit zoning bylaw and implementing regulations while members work through technical questions about how the new state rules intersect with local rules for preexisting nonconforming structures.

Town counsel Jay Talman, who joined the meeting to answer board questions, told the board the ADU law is “a use statute under the Dover Amendment, section 3 of chapter 40A,” and that creates by‑right status for qualifying ADUs but does not change separate statutes that govern dimensional or nonconformity review. “If you have a preexisting nonconforming single‑family house that doesn’t comply with a setback, any addition to that of any kind of size is going to have to get a special permit from the zoning board of appeals,” Talman said.

The discussion focused on several points the board asked counsel to clarify: whether to keep the town’s existing accessory‑apartment special‑permit path while adding a new “protected ADU” bylaw; whether a detached 900‑square‑foot ADU remains by‑right when lot-area or other dimensional controls differ;…