Jefferson County, WI Accessory Structures: Shed & Carport Rules (2026)

" The 500-square-foot figure is a combined ceiling on total ground area covered by buildings in that category, not a per-structure limit, so a homeowner has to add up every qualifying accessory feature on the lot rather than measuring the shed alone. Once combined coverage passes 500 square feet, the code no longer treats the extra area as an ordinary residential accessory use; instead it falls under "extensive parking or storage," a distinct use classification that carries its own zoning review in districts such as R-1 and R-2 (see § 22-125, listing extensive on-site parking or storage as a conditional use in the R-1 Residential-Sewered District).

Practically, that means a shed that pushes a lot's combined driveway, patio and storage coverage over 500 square feet cannot simply be built by right; it needs a conditional use permit reviewed by the planning and zoning committee rather than a routine zoning and land use permit. Height for accessory buildings in the R-1 district is separately capped, per § 22-131, by cross-reference to § 22-676(1). General chapter 22 enforcement, § 22-22, applies to any construction that proceeds without the required permit or classification.