Accessory Structures in Janesville, WI (2026)
2 verified accessory structures rules for Janesville, Wisconsin, sourced directly from the municipal code and official government pages.
Verified from official government sources
ADU Rules
Janesville zoning is in Chapter 42 of the Code of Ordinances. The current code (adopted 1981) does not provide a separate accessory dwelling unit (ADU) classification; second dwellings are regulated through the underlying residential district standards. The R1 district permits single-family and two-family dwellings, so a duplex on a conforming lot is the typical path for adding a second unit. The City is undertaking a Zoning and Subdivision Code Rewrite (Spring 2024 - Summer 2025) that explicitly studies ADUs, tiny homes, and alternative housing as part of Article 8 (Alternative Development Options).
accessory-structures/adu-rules
Some RestrictionsShed Rules
Sheds in Janesville are accessory buildings governed by Section 42-121 of Chapter 42 (Zoning) of the Janesville Code of General Ordinances. The Janesville Building Division does not require a building permit for a residential storage building under 80 square feet, but all applicable zoning setbacks and accessory-structure standards in Chapter 42 still apply.
Shed Rules in Janesville
Some RestrictionsLooking for Rock County county-wide rules?
County ordinances apply to unincorporated areas and may supplement Janesville city rules.
Accessory Structures in Rock County →