Off-Grid Living in Fergus County, Montana

If you're eyeing land in Fergus County, Montana for an off-grid setup, here's my honest read after digging through the official sources.

Zoning. Fergus County doesn't have a countywide zoning ordinance. The Fergus County Planning Office handles subdivision review, floodplain rules, and a Development Permit/addressing process instead of parcel-by-parcel use zoning. That means outside the towns (Lewistown, Moore, Denton, each with their own arrangements), you have a lot more flexibility than in a zoned county, but you still need to go through the county's Development Permit process before building.

Dwellings, tiny homes, RVs. I didn't find a Fergus County ordinance specifically calling out tiny homes or RVs. You'll still need that Development Permit, which checks for road, property, and floodplain issues before construction. Beyond that, my guess is the state baseline (IRC Appendix Q for tiny homes, separate rules for RVs) fills in the gaps, but confirm specifics with the Planning Office.

Building codes. I found no evidence Fergus County runs its own certified building code enforcement program, so it likely falls under Montana's state Building Codes Program by default. Under state law, certain structures are exempt from needing a state building permit, including farm/ranch buildings and residential buildings with fewer than five units (outside transient use) in uncertified areas. Either way, the county's Development Permit for land use is a separate requirement you can't skip.

Septic. This one's clear: the Fergus County Health Department administers septic permitting locally, using minimum sizing standards set by the State of Montana. You'll need a completed application, a site evaluation (done by a certified installer or the County Sanitarian), and county sign-off before installing a system. Composting toilets aren't addressed separately in what I found, so I'd call the Health Department directly to ask how they're treated.

Greywater. No county-specific greywater ordinance turned up. The county's septic regulations do mention "irrigation systems" for subsurface wastewater application, which suggests greywater-for-irrigation might fall under that same wastewater permitting framework, but it's not spelled out. Assume the state baseline otherwise applies.

Rainwater harvesting. I found no county restriction here. Basic rooftop collection for personal, non-potable use appears to be fine under the state baseline.

Wells & water rights. No Fergus County-specific well ordinance beyond noting wells as a site feature in the Development Permit process. Well permitting and exempt-well status run through Montana DNRC at the state level.

Utility disconnection. I found nothing mandating a hookup to grid power, water, or sewer for a private single-family home. The Development Permit process does check septic and floodplain status when assigning addresses, which acts as a practical baseline review even without an explicit "must connect" rule.

Bottom line: Fergus County leaves a lot to the state, but don't skip the county's Development Permit and septic permit steps.