Building permits, zoning and septic rules in St. Clair County, Michigan

Construction and changes in building use or occupancy in St. Clair County require a building-permit application to the appropriate state or local enforcing agency¹. Ordinary repairs are exempt, but structural work, changes to required exits and work affecting public health or safety fall outside that exemption¹. One- and two-family dwellings fall under the Michigan Residential Code; Michigan’s 2015 residential standards remain in effect while the court order described by LARA remains in place^1,2. Riley Township separately adopted a local building code⁸. The enforcing agency periodically inspects permitted construction, and a new or altered building needs a Certificate of Occupancy before use^9,10.

St. Clair County has no county construction-code program; Michigan’s Statewide Jurisdiction List identifies the enforcing agency, including state enforcement in the Village of Emmett². Building permits are handled locally in Marine City¹, Mussey Township¹¹, China Township¹², Cottrellville Township¹. The cities of Richmond¹³ and Memphis¹⁴ reach into St. Clair County and also handle their own building permits. For covered septic systems on St. Clair County land, the St. Clair County Health Department remains the permitting authority⁴. Where LARA enforces the code, building permits can be checked and obtained online or requested by mail; LARA publishes a building-permit fee schedule, while local fees may differ^1,15. Michigan’s owner-builder licensing exception covers a residence built for personal use and occupancy on the owner’s property; building permits still apply⁶.

Zoning on unincorporated St. Clair County land depends on the township governing the parcel; the county’s generalized GIS zoning layer is a staff interpretation, so obtain the official map and ordinance from the local community office^3,16. Local zoning is confirmed in Marysville¹⁷, St. Clair¹⁸, Algonac¹⁹, Mussey Township²⁰, China Township²¹, Cottrellville Township²², Ira Township²³, East China Township²⁴. The cities of Richmond²⁵ and Memphis²⁶ reach into St. Clair County and set their own zoning. Covered septic systems on St. Clair County land still go through the St. Clair County Health Department⁴. Ask the parcel’s local zoning office about setbacks, lot and dwelling size, accessory dwellings and agricultural uses; we could not confirm countywide answers for those questions.

The St. Clair County Health Department issues sewage permits for properties without public sewer; the county instructions cover residential and commercial buildings generating less than 10,000 gallons per day⁴. Obtain the sewage permit before installing or repairing a covered septic system⁴. Only 0.1% of St. Clair County’s mapped soil is rated free of severe limits for a conventional drain field, so resolve septic feasibility before committing to a house site⁷. We could not confirm the local septic-inspection schedule or the permitting route for larger-flow systems; ask the Environmental Health Division at (810) 987-5306 about the evaluation and approvals your project needs²⁷.

We could not confirm a countywide rule allowing RV or tiny-home occupancy on private land in St. Clair County. Ask the zoning office for the parcel’s township, city or village about residential use, temporary camping and minimum dwelling size; applicable land-use controls vary by community³. Michigan’s campground rules do not establish permission to live in an RV on a private parcel²⁸. Household sanitary sewage must go to a municipal sewer or an onsite septic system, so an off-grid plan still needs an approved sewage-disposal route²⁹.

1. Identify the parcel's township, city or village, confirm its zoning district, and ask the local zoning office whether the proposed use and site plan comply¹⁶.
2. Use the Statewide Jurisdiction List to find the correct building-code agency; do not apply to the county, which has no code program².
3. Submit the building-permit application and required construction documents to that enforcing agency before construction¹.
4. If public sewer is unavailable, obtain the county Health Department's sewage permit before installing or repairing septic⁴.
5. Submit the private-well application, site plan and fee to the county Health Department before well work begins⁵.
6. Obtain a Road Commission permit for residential driveway work in its public right-of-way, or the applicable MDOT permit on a state highway^30,31.
7. Complete required approvals and obtain a Certificate of Occupancy before moving in¹⁰.

Access: residential work in the St. Clair County Road Commission right-of-way requires a paid driveway permit and a pre-issuance inspection, usually within 10–14 working days; review covers sight distance, drainage and safety³⁰. An existing driveway may also need inspection for new construction³². Water: submit a private-well application, site plan and fee before work; a residential Type III permit costs $225⁵. Soil erosion: the county lists a $300 residential soil-erosion and sedimentation-control permit fee, distinct from building and well fees; confirm applicability with Environmental Health³³. Land division: proposed subdivision plats receive County Plat Board review under state law³⁴. Taxes: the effective rate is about 1.2%, with a median annual bill about $2,493⁷.