Off-Grid Living in Marion County, Ohio

I'll say this up front: Marion County, Ohio is one of those places where "what are the rules?" doesn't have one answer. There's no countywide zoning code here. Zoning in Ohio is a township and municipal power, and the Marion County Regional Planning Commission's own document center proves it, listing separate zoning resolutions for the City of Marion, Big Island Township, Claridon Township, Grand Township, Grand Prairie Township, Marion Township, and the villages of Caledonia, Green Camp, and Larue. So the very first thing I'd tell anyone eyeing land here is: find out exactly which township or village the parcel sits in, because that entity's zoning resolution controls lot size, setbacks, and what kind of dwelling you can put up.

Because zoning is fragmented, I couldn't confirm a single county-level answer on tiny homes or RVs as permanent dwellings either. Ohio's state law does require that HUD-code manufactured homes be allowed anywhere single-family homes are allowed, but local townships can layer on their own minimum size or appearance rules, so that's a call-your-township question.

Building permits are similarly split. Ohio law lets counties adopt their own residential building rules, but those can't be looser or stricter than the state Residential Code of Ohio except on topics the state code doesn't cover. The City of Marion has its own certified building department under Chief Building Official Eric Shaver. Whether unincorporated county land or the townships have a separate certified department, or defer to the state, wasn't confirmed in what I found, so that's a phone call to make before you build.

Septic is more settled: Marion Public Health runs the household sewage treatment system (HSTS) program under the statewide Ohio sewage rules (OAC 3701-29), and their own materials note that much of the county is unsewered, meaning an individual home sewage system is often a necessity, not an option. Composting toilets specifically aren't addressed in what I found, so I'd ask the health district directly. Greywater and rainwater harvesting are in the same boat, the state framework exists but Marion Public Health hasn't published anything I could find that's specific to either, so treat both as open questions for that office.

Private wells fall under Marion Public Health too, working from the state's private water systems rules, though I couldn't find a dedicated well-permitting page beyond a reference to combined "Health permits (Sewage and/or Water)."

And living fully off-grid, disconnected from utilities? I found nothing at the county or township level that mandates a utility hookup, but you'd still need to clear whatever building code and health-district permitting applies to your specific township.