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

A Uniform Dwelling Code building permit is required for a new one- or two-family dwelling in Sauk County, including stick-built, modular and manufactured-home installations¹. The UDC is Wisconsin's statewide building code and applies the same way in every county, covering one- and two-family dwellings built since June 1, 1980; Sauk County municipalities contract with private building inspectors for local administration^2,15. New homes require footing, foundation and reinforcement, rough, insulation and final inspections¹. A Sauk County owner who occupies or will occupy the dwelling may apply without Dwelling Contractor Certification by making the owner-occupant attestation in the electronic application; building permits, code compliance and inspections still apply^12,15.

Sauk County’s Town Building Inspectors page identifies the municipality’s contracted inspector and advises contacting the town chair or clerk about additional local building permit requirements². Wisconsin Dells, mainly in Columbia County but extending into Sauk County, issues its own building permits¹⁶. Sauk County administers septic rules countywide; Wisconsin Dells also requires a city private-sewage permit before construction when public sewer is unavailable^4,17. Sauk County Land Resources and Environment handles county zoning and land-use approval at 505 Broadway in Baraboo, phone (608) 355-3245¹³. County land-use and sanitary applications use the OpenGov portal⁵. Each municipality sets its UDC building permit fees by ordinance, and a $30 state permit-seal fee applies to each new dwelling¹⁸. The county's planning and zoning fee schedule is published but may not be all-inclusive, and fee changes accompany the zoning rewrite, so ask department staff about project-specific fees¹⁹.

Sauk County zoning applies to unincorporated land in towns covered by Chapter 7; city, village, extraterritorial or town zoning may govern other parcels, and some areas may have no zoning district^6,7. Wisconsin Dells, a city reaching into Sauk County from Columbia County, sets its own zoning; Sauk County retains septic administration, with an additional city private-sewage permit where public sewer is unavailable^4,17,20. The county’s Zoning District Finder uses the official digital GIS map; a blank area may be under another zoning authority or have no zoning⁷. The rewrite changes districts and adds overlay districts, but the prior ordinance remains effective in a covered town for one year or until town adoption, whichever comes first³. Ask Zoning Services which ordinance version and district apply; we could not confirm current parcel-specific minimum home size, lot size, ordinary setbacks, lot coverage or height standards^7,13.

Sauk County Land Resources and Environment administers septic permits for private onsite wastewater systems throughout Sauk County, including addresses where another local government handles building permits or zoning^8,21. A sanitary permit is required for covered construction, alteration, changes of use or placement of a human-habitation structure that needs a POWTS⁸. Depending on the project, the application may require approved plans, a soil test report, a plot plan, fees and other listed materials; a new residence cannot be occupied until the system is installed and fully functional⁸. Published fees include $450 for a conventional system and $550 for a holding tank, and septic fees double if work begins without septic permits⁹. Submit the septic permit application online and allow for the published 7–10-day review period¹⁴. Test feasibility early because only about 3.2% of Sauk County soils are rated without severe limitations for a conventional drain field²².

On unincorporated land subject to Sauk County’s Chapter 7 camping rules, an RV or other camping unit cannot serve as a permanent abode or legal residence¹¹. The county camping page allows up to 6 stays of 15 consecutive days or one 45-day stay annually, generally with a land-use camping permit in specified districts¹⁰. The 2026 Chapter 7 draft instead limits non-campground stays to 15 consecutive days and 45 days total annually; removal or enclosed storage and at least three camping-unit-free days between stays are required¹¹. Ask Zoning Services which camping schedule governs the parcel because town adoption affects the applicable ordinance^11,13. We could not confirm a tiny-home classification; ask the zoning authority how the design is treated and the municipality’s inspector about dwelling building permits^1,2,7.

1. Identify the municipality and use the county zoning map to determine whether county, town, city, village or extraterritorial zoning applies⁷.
2. Ask the applicable zoning authority about the proposed use, district standards and land-use approval; ask Sauk County about its published fees and any subdivision, plat or certified-survey-map review^19,23,24.
3. Complete the soil evaluation and obtain the Sauk County septic permit before seeking a building permit for a new home served by private septic^8,15.
4. File county land-use and septic permit applications through the online portal and plan around the published 7–10-day review time^5,14.
5. Find the municipality's contracted inspector and submit the UDC building permit application, plans, required data and fee^1,2.
6. Schedule the required footing, foundation and reinforcement, rough, insulation and final inspections¹.

Before dividing Sauk County land, ask Planning and Zoning about Chapter 22 land-division review and submit certified survey maps through the county portal^23,24. Published review fees include $100 plus $20 per additional lot for a certified survey map and $300 plus $20 per lot for a preliminary subdivision plat; confirm current charges with staff because zoning-rewrite fee changes are also published^9,19. Only about 3.2% of Sauk County soils are rated without severe limitations for conventional septic drain fields, so evaluate soils before fixing a house site²². Ask Zoning Services about floodplain approval and applicable waterfront standards^13,21,25. A new ordinary private well requires advance DNR construction notification; any additional Sauk County well permit remains unconfirmed^13,26. New or altered state-highway driveway connections require WisDOT approval; ask Zoning Services who handles access from county or local roads^13,27.