Off-Grid Living in Park County, Montana

I've spent a good chunk of time digging through Park County, Montana's official pages, and the honest headline is: this is a patchwork county, not a place with one clean set of off-grid rules. Here's what I found.

Zoning. Park County has no countywide zoning code. Instead, there are seven mapped zoning districts (six citizen-initiated, one county-initiated) scattered around places like Paradise Valley, East Yellowstone, Suce Creek, Cokedale, Cooke City-Silver Gate-Colter Pass, O-Rea Creek, and the US Hwy 89 S corridor. If your parcel sits inside one of those districts, that district's own rules govern what you can do with the land. Outside those districts, the county itself doesn't zone, though that doesn't mean anything goes, check the Planning Department's map before assuming raw land is a blank slate.

Dwellings, tiny homes, RVs. I couldn't find a Park County ordinance specifically addressing tiny homes, so I'd presume the state's IRC Appendix Q baseline applies here as inherited. Watch two things: the county's floodplain regulations can classify a long-term-parked RV or trailer as a "manufactured or mobile home," and if you're putting in two or more RV or mobile home spaces, that triggers county subdivision review by the County Commission.

Building permits. This one's genuinely murky. Montana law lets counties opt into their own building code program (certified by the state Building Codes Program) or default to state enforcement. I could not confirm whether Park County has adopted its own residential building code; the Planning Department page mentions "building for lease or rent" as something it touches, which hints at some oversight, but nothing definitive. Call Planning to confirm where your project falls.

Septic and greywater. This is the one area that's clearly and consistently regulated countywide. Park County Environmental Health administers septic permitting under its own Onsite Wastewater Treatment Regulations, permits are required, inspections happen before backfilling, and the county Board of Health can grant variances under state rule (A.R.M. 17.36.922) when warranted. Greywater isn't separately addressed, so it's presumably folded into that same onsite wastewater framework.

Rainwater and wells. No county ordinance restricts rooftop rainwater collection, so the state's permissive baseline applies. Wells fall under Montana DNRC's exempt-well framework statewide; the county's Environmental Health office may keep related paperwork tied to septic site evaluations, but permitting itself is a DNRC matter, not a county one.

Utility disconnection. I found no Park County rule requiring you to hook up to grid power or municipal water/sewer to legally occupy a home. The real approval choke points remain septic permitting and, if applicable, zoning/floodplain review.

Bottom line: septic is your firm requirement everywhere in the county; zoning and building codes depend heavily on exactly where your parcel sits, so a phone call to Planning is worth it before you buy or build.