Boston, MA Building Setbacks & Zoning: Setback Rules (2026)

Building setbacks in Boston are governed by the Boston Zoning Code, which establishes minimum distances between structures and property lines for each zoning district. In residential subdistricts (1F, 2F, 3F), front yard setbacks typically range from 15 to 25 feet, with contextual provisions that may adjust the requirement based on the average setback of existing buildings on the block. Side yard setbacks in residential zones are generally 5 to 10 feet, and rear yard setbacks are typically 30 feet or 30% of lot depth, whichever is less. In mixed-use and commercial districts, setback requirements are often reduced or eliminated for buildings fronting on commercial streets. The Boston Zoning Code includes a provision allowing the prevailing setback pattern on a street to establish the required setback (contextual setback). Additions and renovations must comply with current setback requirements or obtain a variance from the Zoning Board of Appeal (ZBA). The BPDA reviews Article 80 large project developments for compliance. Porches, stairs, and certain architectural features may encroach into setback areas with ZBA approval.