ADU Permit Process in Massachusetts, Step by Step
A qualifying ADU is generally allowed by right for zoning, but it still needs a complete building permit, code-compliant plans, and inspections under 780 CMR. In Cambridge, the practical schedule depends on both the project's eligibility and the town reviews its plans must pass. A Cambridge homeowner might be weighing a small backyard cottage against […]
ADU Size Limit: A Massachusetts Homeowner Guide
A protected-use ADU in Massachusetts may be up to 900 square feet or 50% of the principal dwelling's gross floor area, whichever is smaller, under the statewide rule effective January 31, 2025. A 1,400-square-foot main house, for example, may limit the ADU to 700 square feet, even though the statutory ceiling is 900 square feet. […]