Off-Grid Living in Sanilac County, Michigan

Sanilac County, Michigan is a place where I have to be upfront: there's no countywide zoning ordinance here. Zoning is handled township by township under Michigan's Zoning Enabling Act, so whether you can just buy raw land and live on it depends entirely on which township your parcel sits in. What is consistent countywide is that the Sanilac County Department of Construction & Land Use issues building permits and enforces construction codes, and the Sanilac County Health Department's Environmental Health Division handles septic and well permitting everywhere in the county.

For zoning and raw-land occupancy, I'd start with your specific township office. Sanilac Township, for example, lists permitted uses by district in its own ordinance, and a township Land Use Permit has to accompany any county building permit application. That structure is likely mirrored (with variations) in other townships, but I can't tell you what your particular township allows without you calling them.

On dwellings, tiny homes, and RVs: the county's construction department enforces the Michigan Residential Code, and at least in Sanilac Township, the ordinance explicitly excludes recreational vehicles from qualifying as a "dwelling." So don't count on living in an RV long-term as your legal residence, at least not without checking your township's specific rules.

Building permits themselves come from the county, not the township, but you generally need the township's zoning sign-off first. The county's guidance also pointedly tells homeowners to use only state-licensed contractors, though it puts the burden on the permit holder to actually know which codes apply.

Septic systems require a permit from the county Health Department, which administers Michigan's Public Health Code locally. I did not find any official confirmation that composting toilets are accepted as a sole system here, so if that's your plan, ask the Health Department directly before you build around that assumption.

Greywater reuse and rainwater harvesting don't appear to have Sanilac-specific rules on the books. Both would fall back to Michigan's statewide plumbing code and related state law, administered by LARA, but I'd call the county to confirm nothing local has been layered on top.

Private wells are permitted, but require a county Health Department permit and follow the state's Water Well Construction Code as enforced locally.

As for going fully off-grid with no utility hookups: I found no outright county ban, but at least Sanilac Township's ordinance requires an approved on-site well and septic system when public water/sewer isn't available, meaning "no system at all" isn't a legal option for a permitted dwelling. This is the practical reality across most of rural Michigan, and it likely holds true in other Sanilac townships too, though you should confirm locally.