Building permits, zoning and septic rules in Grant County, Wisconsin

Grant County, Wisconsin requires a Uniform Dwelling Code building permit for a new one- or two-family home, including seasonal and recreational dwellings¹. Detached garages and accessory buildings are outside the UDC's coverage, but county zoning requirements may still apply^1,8. The issuing authority may be a delegated municipality, a delegated county or the Wisconsin Department of Safety and Professional Services, so confirm the building inspector for the parcel before applying¹². Permit requirements for additions and alterations vary by municipality¹. Call for building inspections before covering each construction phase; the inspector has two business days after the request and readiness of the work before covering may proceed under the stated conditions¹. Occupancy follows a final inspection finding no major health or safety violations¹. An owner who occupies or will occupy the home may obtain the construction and erosion-control permits, but that allowance does not waive the building permit or code compliance¹.

The building inspector for the parcel issues the Uniform Dwelling Code building permit; Wisconsin assigns that role to a delegated municipality, a delegated county or the state depending on jurisdiction¹². Inside Lancaster, the city's own building inspector issues building permits¹³. For land outside city limits, Grant County's Conservation, Sanitation & Zoning Department is the local contact at 150 W Alona Lane in Lancaster, phone (608) 723-6080². For a home with internal plumbing in county zoning jurisdiction, Grant County issues the sanitary permit first and the zoning permit second; the building inspector then uses both permit numbers for the building permit⁵. Even where a city, village or town handles the building permit or zoning approval, Grant County still administers the septic permit throughout the county². County zoning fees use estimated project value, with a $100 minimum and a higher rate at $300,000¹⁴.

Grant County administers comprehensive zoning in listed unincorporated towns, with exclusions for land under a municipality's extraterritorial zoning^2,8. The county list names Boscobel, Clifton, Ellenboro, Fennimore, Harrison, Hickory Grove, Jamestown, Liberty, Lima, Millville, Mt. Hope, Mt. Ida, Muscoda, Paris, Potosi, South Lancaster, Watterstown and Wingville². Elsewhere, local zoning varies: Lancaster zones inside the city⁴, and the City of Platteville administers zoning within the city and, with the Town of Platteville, in its surrounding extraterritorial area⁶. Beetown and Bloomington list interim zoning ordinances; the Town of Bloomington's is dated June 8, 2026, and we could not confirm its coverage, so ask each town^15,16. Grant County still administers septic permits countywide². Ask the county zoning office to identify the parcel's authority and mapped district; shoreland and floodplain rules may apply separately^2,3,8. Lot dimensions, dwelling size, height and setbacks vary by district⁸. Where a land division is a subdivision in unincorporated areas, lots without public sewer must be at least 20,000 square feet and 100 feet wide, and lots outside shoreland with public sewer at least 8,000 square feet and 70 feet wide^8,9. Farmland Preservation allows listed agricultural uses without a conditional-use permit, but keeps agricultural-district setbacks and other requirements⁸. The 30% coverage cap applies to planned commercial and industrial development, not every residential lot⁸.

Wisconsin regulates private onsite wastewater treatment systems, while Grant County administers local sanitary permits and maintenance^2,17. A POWTS permit must be issued before installation, and a Wisconsin-licensed Master Plumber or Master Restricted Sewer Plumber must install the system¹⁸. Grant County must inspect an installation, replacement, modification, reconnection, or removal before the system generally enters service¹⁹. Existing systems outside public-sewer service require licensed inspection or pumping every 3 years, followed by certification to the county and the maintenance fee⁷. Permit fees are $400 for listed systems under 1,000 gallons per day and $500 for systems over that design flow¹⁸. Only 2.8% of county soils are rated without severe limitations for a conventional drain field, so make the soil evaluation an early purchase contingency¹¹. Non-plumbing sanitation systems and vaulted privies remain permit matters rather than automatic off-grid exceptions²⁰.

In unincorporated Grant County under county zoning, planned trailer parks and campgrounds require planned-development approval, may operate only in Conservancy-Forestry-Recreation, Shoreland and Flood Plain districts, and allow seasonal use of no more than 30 days per trailer or campsite⁸. Planned campgrounds require at least 10 acres and allow at most 10 units per gross usable acre². We could not confirm temporary construction use or year-round occupancy of one RV on an ordinary private parcel in Grant County; ask the zoning office about the address and proposed duration². A dwelling under 800 square feet in county-zoned Agricultural A-1 requires a conditional-use permit and remains subject to dimensional, setback and sanitation rules⁸. County-zoned R-1 prohibits a separate dwelling in an accessory structure, and that restriction carries into R-2 and R-3⁸. A manufactured home under county zoning needs zoning approval, valid manufacturer's certification and generally at least 24 feet of width; a single unit on an operating farm is exempt from the width rule only, with other zoning, sanitary and building rules still applying⁸.

1. Confirm which county, town, municipal or extraterritorial zoning authority governs the parcel and identify its mapped district^3,8.
2. If the home will use septic, obtain the soil evaluation and Grant County sanitary permit before seeking county zoning approval^2,18.
3. Apply to the governing zoning authority for zoning approval, including any required shoreland or floodplain application; the county process requires a plot plan and fee^5,14.
4. Obtain the town driveway permit and resolve road-class access and setback standards⁸. A state-highway connection separately requires a WisDOT driveway permit²¹.
5. Apply to the responsible municipal, county or state inspector for the Uniform Dwelling Code building permit¹².
6. Call for each building inspection before covering work and obtain the final inspection before occupancy¹.
7. Schedule Grant County's septic installation inspection before placing the POWTS into service¹⁹.

A new private well that is not high-capacity requires a Wisconsin DNR Well Construction Notification Number before construction²². We could not confirm an additional Grant County well permit or a countywide public-water or sewer connection mandate; ask Conservation, Sanitation & Zoning about the parcel². Confirm the zoning authority, mapped district, lot dimensions and allowed use because zoning varies across Grant County^3,8. Check front, side, rear and highway setbacks before choosing a building site⁸. In unincorporated shoreland, structures generally need a 75-foot setback from the ordinary high-water mark, structures within that band are capped at 35 feet, and impervious coverage generally starts at a 15% limit¹⁰. A mapped floodplain requires a floodplain application before construction¹⁰. Confirm legal access and the town driveway permit before purchase⁸. Typical property tax is about 1.4%, with a median annual bill near $2,683¹¹.