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

Section 290-27 of the Grant County floodplain zoning chapter sets standards for development in the Flood-Fringe District, and Subsection B addresses accessory structures or uses: they shall be constructed on fill with the lowest floor at or above the regional flood elevation. Section 290-26 allows any structure, land use or development in the flood-fringe if the § 290-27 standards are met, the use is not prohibited by the chapter or any other ordinance or regulation, and all permits or certificates specified in § 290-36 have been issued.

Storage matters too: under § 290-27E, materials that are buoyant, flammable, explosive, or injurious to property, water quality or human, animal, plant, fish or aquatic life must be stored at or above the flood protection elevation or floodproofed in compliance with § 290-40. Near water the Shoreland Protection Ordinance adds its own limits. Section 316-25A requires a setback of 75 feet from the ordinary high-water mark for all buildings and structures unless an exemption applies. The exempt structures in § 316-25B include one boathouse per lot, which the code calls an accessory structure, limited to one story and 300 square feet in floor area, and open-sided or screened structures such as gazebos, decks, patios and screen houses, whose combined floor area in the setback area cannot exceed 200 square feet and whose nearest part must sit at least 35 feet landward of the ordinary high-water mark.

In the Shoreland-Wetland District, § 316-14C(2) allows a nonresidential building with a zoning permit only if it is essential for and used solely with raising waterfowl, minnows or other wetland or aquatic animals or another permitted use, cannot as a practical matter be located outside the wetland, is not designed for human habitation, and does not exceed 500 square feet in floor area. Section 316-53A requires a permit from the Zoning Administrator before any new development, and under § 316-53C a zoning permit expires 12 months from the date issued if no substantial work has commenced.