St. Croix County, WI zoning map, flood zone and property lines by address
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Flood zone by address
ParcelSheet reads FEMA's National Flood Hazard Layer at the lot: the zone, whether it is a high risk area where lenders ask for flood insurance, and the base flood elevation where FEMA lists one. FEMA's countywide study for St. Croix County has 172 FIRM panels, the newest effective March 2009; no coastal V zones are mapped in it.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a St. Croix house comes from a licensed surveyor and is often on file with the county or city building office.
Property lines
The parcel outline, parcel number and mapped size come from the Wisconsin statewide parcel layer (from each county, compiled by the State Cartographer), so a St. Croix lot shows the same lines the real property lister draws. St. Croix County covers about 462,181 acres of land and 8,337 acres of water.
Mapped lines are approximate. The St. Croix County real property lister keeps the parcel record (St. Croix County website); a licensed surveyor sets the true corners.
Zoning
In Wisconsin zoning is set by the county, the town or the city or village, depending on where the lot is. ParcelSheet shows the use code on the lot's parcel record and the municipality it sits in; the county, town or city zoning office has the district, the uses it allows and the lot size it needs. The St. Croix County website lists the county's municipalities.
ADU and guest houses
Under Wisconsin's zoning laws (Wis. Stat. 59.69 for counties, 60.61 for towns and 62.23 for cities), the county, the town or the city or village, depending on where the lot is can allow an accessory dwelling unit on a lot with a house. Whether a St. Croix lot can add one depends on its district; the county, town or city zoning office has the rule. ParcelSheet shows the mapped lot size and the ground's slope, the first two things the question turns on.
Septic and soil
ParcelSheet reads the USDA soil survey at the lot: the soil's name, its septic absorption rating and whether it is prime farmland. St. Croix County is soil survey area WI109, St. Croix County, Wisconsin, last updated September 2026, on Web Soil Survey.
A new or changed septic system in St. Croix County needs a permit from the St. Croix County sanitary permit office under the state POWTS rules (Department of Safety and Professional Services).
Setbacks
Setbacks in St. Croix County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the county, town or city zoning office gives them for the lot's district.
Hazards that apply
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a St. Croix lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in St. Croix County?
Type the address in the box above and ParcelSheet reads FEMA's flood zone at the lot's center. FEMA's countywide flood map for St. Croix County has 172 panels, the newest effective March 2009. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in St. Croix County?
Open the Wisconsin map, type the address, and the parcel outline from the St. Croix County real property lister shows on the map with its parcel number and mapped size. Mapped lines are approximate; only a licensed surveyor sets the true corners.
What is my property zoned in St. Croix County?
Zoning in St. Croix County is set by the county, the town or the city or village, depending on where the lot is. ParcelSheet shows the use code on the parcel record and names the municipality; the county, town or city zoning office has the final word.
Can I build an ADU in St. Croix County?
Under Wisconsin's zoning laws (Wis. Stat. 59.69 for counties, 60.61 for towns and 62.23 for cities), the county, the town or the city or village, depending on where the lot is can allow an accessory dwelling unit, and each sets its own rules. In St. Croix County ask the county, town or city zoning office for the lot's district first; ParcelSheet shows the lot size as mapped so you can see the room you have.
Do I need a septic permit in St. Croix County?
Yes. A new or changed septic system in St. Croix County needs a permit from the St. Croix County sanitary permit office under the state POWTS rules (Department of Safety and Professional Services). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area WI109 (St. Croix County, Wisconsin).
What can I build on 5 acres in St. Croix County?
Zoning in St. Croix County is set by the county, the town or the city or village, depending on where the lot is. The zoning district decides the uses, how many homes and the smallest lot it allows on 5 acres. ParcelSheet shows the lot size as mapped and the use code on the parcel record; the county, town or city zoning office has the district and its rules. See the St. Croix County website.
What are the residential setbacks in St. Croix County (2026)?
Setbacks in St. Croix County come from the zoning code of the municipality the lot sits in: the front, side and rear distances depend on the lot's district. ParcelSheet does not draw setback lines or give a number it did not read; the county, town or city zoning office gives them for the district. See the St. Croix County website.
Next to St. Croix County: Dunn County, Pierce County, Polk County.
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