St. Clair County, MI 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. Clair County has 135 FIRM panels, the newest effective July 2022; coastal V zones, where waves add to the flood, are mapped along its shore.
The official panel and any Letter of Map Amendment are at FEMA's Map Service Center. An elevation certificate for a St. Clair 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 Michigan county parcel layers (each county publishes its own), so a St. Clair lot shows the same lines the township or city assessor draws. St. Clair County covers about 461,774 acres of land and 73,584 acres of water.
Mapped lines are approximate. The St. Clair County township or city assessor keeps the parcel record (St. Clair County website); a licensed surveyor sets the true corners.
Zoning
In Michigan zoning is set by the county, the township, 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 township or city zoning office has the district, the uses it allows and the lot size it needs. The St. Clair County website lists the county's municipalities.
ADU and guest houses
Under Michigan Zoning Enabling Act (Public Act 110 of 2006, MCL 125.3101 and following), the county, the township, 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. Clair lot can add one depends on its district; the township 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. Clair County is soil survey area MI147, St. Clair County, Michigan, last updated August 2026, on Web Soil Survey.
A new or changed septic system in St. Clair County needs a permit from the St. Clair County health department (local health department, under Michigan EGLE onsite wastewater rules).
Setbacks
Setbacks in St. Clair County come from the zoning district: the front, side and rear distances a house must keep. ParcelSheet does not draw setback lines; the township or city zoning office gives them for the lot's district.
Hazards that apply
- Storm surge. St. Clair County has coastal V zones on its FEMA map, so storm surge reaches its shore. The county's evacuation zones are on its emergency management site; ParcelSheet shows the FEMA zone and the 3 ft sea level rise map at the lot.
- Wetlands and wildfire. ParcelSheet shows the National Wetlands Inventory near a St. Clair lot and the Forest Service wildfire hazard rating at it.
Questions
Is my house in a flood zone in St. Clair 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. Clair County has 135 panels, the newest effective July 2022. A lender or insurer uses the official FIRM panel; FEMA's Map Service Center has it.
How do I find property lines in St. Clair County?
Open the Michigan map, type the address, and the parcel outline from the St. Clair County township or city assessor 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. Clair County?
Zoning in St. Clair County is set by the county, the township, 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 township or city zoning office has the final word.
Can I build an ADU in St. Clair County?
Under Michigan Zoning Enabling Act (Public Act 110 of 2006, MCL 125.3101 and following), the county, the township, 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. Clair County ask the township 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. Clair County?
Yes. A new or changed septic system in St. Clair County needs a permit from the St. Clair County health department (local health department, under Michigan EGLE onsite wastewater rules). ParcelSheet shows the USDA soil survey's septic rating at the lot, from survey area MI147 (St. Clair County, Michigan).
What can I build on 5 acres in St. Clair County?
Zoning in St. Clair County is set by the county, the township, 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 township or city zoning office has the district and its rules. See the St. Clair County website.
What are the residential setbacks in St. Clair County (2026)?
Setbacks in St. Clair 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 township or city zoning office gives them for the district. See the St. Clair County website.
Next to St. Clair County: Lapeer County, Macomb County, Sanilac County.
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