Walworth County, WI Accessory Structures: Shed & Carport Rules (2026)
Shed permit rules in Walworth County, WI, also referred to as storage shed, backyard shed, or accessory building regulations, set size limits, setbacks, and when a building permit is required.
Key Facts
- Small-lot size cap
- 10% of lot area (0-12,000 sq ft parcels)
- Large-lot size cap
- 2% of lot area (5+ acre parcels)
- Height tier 1
- 17 ft max, structures under 1,200 sq ft
- Height tier 3
- 25 ft max, structures over 1,650 sq ft
- Excluded uses
- Ag structures in A-1/A-2/A-3, boathouses
Summary
Sheds and other accessory buildings in unincorporated Walworth County are capped by lot size under Walworth County Code § 74-38: a parcel up to 12,000 square feet is limited to 10 percent lot coverage in accessory structures, and structures 1,200 square feet or smaller cannot exceed 17 feet in height.
Accessory structure, size, height and locational requirements. The size (square footage at ground floor elevation) of accessory structures shall be based on lot area. The lot area shall be considered the net area less areas zoned C-1 and C-4. The total accessory structure floor area shall be calculated as follows: Parcel from 0 to 12,000 square foot is limited to 10% of lot area in accessory structures; Parcel 12,001 sq. ft. to 40,000 sq. ft. is limited to 1,650 sq. ft. of accessory structures; ... Accessory structures 1,200 square feet or less in size shall not exceed 17 feet in height, and accessory structures 1,201 square feet to 1,650 square feet in size shall not exceed 20 feet in height.
Full Breakdown
Sec. 74-38(2) sets accessory structure size on a sliding scale tied to net lot area, which excludes any portion zoned C-1 or C-4. 99-acre brackets before reverting to a percentage cap of 2 percent of lot area for parcels of 5 acres or more. Height is tied to that same size bracket: an accessory structure of 1,200 square feet or less cannot exceed 17 feet, one between 1,201 and 1,650 square feet cannot exceed 20 feet, and anything larger than 1,650 square feet cannot exceed 25 feet and must meet the principal structure's zone-district setbacks.
Location rules require accessory structures to sit in rear or side yards on most lots, with street-yard placement allowed on waterfront, flag, corner, and through lots or lots of an acre or more, and only boathouses, hoists, and piers permitted in the shoreyard. Structures up to 1,650 square feet in the side yard must meet the zone district's side-yard setback; in the street yard they cannot sit closer than the required side, rear, and street yard setback, except five feet from an alley, and waterfront street-yard placement drops to three feet from the lot line, five feet from an alley line, and ten feet from the road right-of-way.
These size, height, and location rules apply to residential-purpose accessory structures in every zone district where they are permitted or conditional, but they do not apply to boathouses or to agricultural accessory structures in the A-1, A-2, and A-3 districts, nor to business, industrial, public, or recreational accessory structures.
Violations & Fines
Erecting or moving an accessory structure that exceeds the size, height, or setback limits of Sec. 74-38, or building one before the principal structure exists, is a zoning violation under Sec. 74-37; the Zoning Administrator must investigate complaints and report violations to the corporation counsel, which can bring an enforcement action.
Frequently Asked Questions
How big a shed can I build on a 1-acre lot in unincorporated Walworth County?
Can I put a shed in my front yard in Walworth County?
Do farm buildings follow the same shed size limits?
Sources & Official References
Other rules in Walworth County
How Walworth County compares: Shed Permit Requirements by City·Compare Walworth County to another location·View the Wisconsin accessory structures overview
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