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

Section 3.1.8 of the Somerville Zoning Ordinance governs the Detached House building type, described in the code as "the most prevalent building type in Somerville," permitted by right in the Neighborhood Residence (NR) district. Its Building Placement table in Section 3.1.8.b sets the primary front setback at a minimum of 10 feet and a maximum of 20 feet, and the secondary front setback (on corner or through lots) at the same 10-to-20-foot range, subject to the contextual front setback rule in Section 3.1.14.a when three abutting lots share an orientation toward the same street.

Side setbacks depend on driveway configuration: the minimum side setback is 5 feet where there is no driveway access or where the driveway runs along the side or rear, dropping to 3 feet where a front driveway crosses the side yard. The sum of both side setbacks together must total at least 10 feet without a driveway, or 12 feet where a front driveway is present. The rear setback minimum is a flat 20 feet, and any principal or accessory building must maintain a 10-foot building separation from other structures on the same or an abutting lot under Section 2.4.3.b.

Section 2.4.3.a measures side and rear setbacks parallel to the lot lines, and the ordinance allows limited encroachments into a setback under Section 2.4.3.d: cornices and sills up to 2 feet, chimneys up to 4 feet, and uncovered patios or underground structures without limit. Parking must additionally sit behind a 20-foot primary front parking setback and a 10-foot secondary front parking setback. These standards took effect November 21, 2023 under Ordinance 2023-23.