Janesville, WI Building Setbacks & Zoning: Setback Rules (2026)

Sec. 42-440(b)(1)e of the Janesville Code of General Ordinances sets the principal-use setbacks for the R1 Single-Family and Two-Family Residence District: a 25-foot front yard, an eight-foot side yard, a 25-foot rear yard except on corner lots, and a 25-foot corner side yard measured from all street lines. A corner interior lot may instead use an eight-foot side yard with a 15-foot rear yard, or a 15-foot side yard with an eight-foot rear yard, whichever combination the owner selects. Accessory buildings get smaller margins under Subsection (f): the front yard follows the accessory setback line in Section 42-119, the side yard is two feet plus the width of the roof eave (unless Section 42-363 applies), the corner side yard stays at 25 feet from all street lines, and the rear yard is again two feet plus the eave.

The same 25/8/25 pattern repeats verbatim for the R1D, R2 and R3M Districts, though R3M widens the side yard to ten feet for buildings of three or more units or nonresidential uses. Where at least half of the three adjacent improved lots on a block already sit closer to the street than these minimums, Section 42-440(a)(5) lets a new house use the computed block average instead, with vacant lots counted at the full required setback. Larger multifamily or nonresidential buildings sited next to an R1 or R2 lot must also pull back a side and rear yard equal to the building's height above grade, or 25 feet, whichever is greater, under Subsection (a)(7). Setback compliance is verified at the building permit stage by the Building Division Director before construction begins.