ADU rules in Marathon County, WI — also called accessory dwelling unit regulations or granny flat ordinances — cover setbacks, owner-occupancy, parking, and permit requirements.
Marathon County zoning (General Code Ch. 17) regulates accessory structures and second dwellings only in the 42 towns that have adopted county comprehensive zoning. Wausau, Rothschild, Schofield, Weston, Mosinee, Kronenwetter, and other incorporated cities/villages administer their own zoning codes. Wisconsin has no statewide ADU mandate.
Marathon County's Conservation, Planning, and Zoning Department administers Chapter 17 zoning under Wis. Stat. §59.69 only in unincorporated towns that have opted into county comprehensive zoning; other towns and all cities/villages set their own rules. ADU permission depends on the parcel's zoning district. New dwelling units must comply with the Wisconsin Uniform Dwelling Code (Wis. Admin. Code SPS 320-325) for one- and two-family dwellings, including egress, energy, and electrical standards. Shoreland-overlay parcels (within 1,000 feet of lakes/flowages or 300 feet of navigable streams) carry additional impervious-surface and setback limits.
Zoning violations under Wis. Stat. §59.69(11) carry forfeitures set by county ordinance, plus daily continuing-violation penalties. Unpermitted dwelling units may require removal or after-the-fact permits.
Marathon County, WI
Marathon County does not impose a countywide decibel-based noise ordinance with fixed quiet hours for unincorporated areas. Public peace matters are addresse...
Marathon County, WI
Fences in unincorporated Marathon County are regulated under Section 17.401.05 (Fence and Wall Regulations) of the county Zoning Code (Chapter 17), administe...
Marathon County, WI
Marathon County requires every dog 5 months of age or older to be licensed annually, with a county-set minimum tax of $12 for a spayed/neutered dog and $20 f...
Marathon County, WI
Wis. Stat. §167.10 requires a user's permit for nearly all consumer fireworks (firecrackers, bottle rockets, Roman candles, mortars, aerial repeaters). Permi...
Marathon County, WI
Marathon County does not run a county-wide STR parking standard. Off-street parking for short-term rentals in unincorporated towns is set by Marathon County ...
Marathon County, WI
Marathon County does not set a county-wide occupancy cap on short-term rentals. Maximum guest count is fixed at the property's annual Tourist Rooming House i...
See how Marathon County's adu rules rules stack up against other locations.
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