Fond du Lac County, WI Accessory Structures: Shed & Carport Rules (2026)

Fond du Lac County Code Sec. 44-83(6) sets the accessory building standard for the recreational-residential shoreland district: garages, sheds, storage buildings and boathouses may not exceed 864 square feet, no more than two accessory structures are permitted on a lot, and none may exceed one story or ten-foot exterior sidewalls. Dormers and attic/storage trusses are allowed, but the structure cannot be used for human habitation and cannot be built as a pole building. A small accessory structure of 120 square feet or less, with sidewalls capped at six feet, may sit as close as five feet to the lot line; every other accessory structure must otherwise meet the district's setback rules, including staying at least 20 feet from any wetland.

Roof pitch on an accessory structure is capped at 4/12, though it may instead match the pitch of the existing principal structure on the same lot. A property owner who wants one larger building instead of two separate accessory structures can apply for an 'oversized accessory structure' up to 1,728 square feet under Sec. 44-83(b), but that building must sit at least 75 feet from the ordinary high-water mark, stay a single story, and be the only accessory structure on the lot. These standards apply only within shoreland areas of unincorporated Fond du Lac County, which covers land within 1,000 feet of a lake or 300 feet of a river or stream; general accessory-building rules outside the shoreland zone are set by the individual town, not the county. Enforcement runs through the Code Enforcement office, which issues the zoning/land use permit required before a shed or garage is built.