Off-Grid Living in Lewis and Clark County, Montana

Lewis and Clark County, Montana, is one of those places where the honest answer to "can I live off-grid here?" is: it depends entirely on where your parcel sits. I want to be upfront that I'm researching this from official county and state sources, not from personal experience buying land here, so treat this as a starting map, not a final answer.

Zoning first, always. Unlike a lot of counties, Lewis and Clark doesn't have one countywide zoning ordinance. The county's Community Development and Planning Department (CDP) administers zoning through a patchwork of Part 1 and Part 2 zoning districts under Montana state law (MCA Title 76), plus a number of citizen-initiated Special Zoning Districts. That means whether you can put a cabin, tiny home, or off-grid structure on raw land depends on which specific district your parcel falls in. Before you do anything else, pull up the county's interactive zoning map and check your parcel, then call CDP or the Planning and Zoning Commission with questions.

Dwellings. I didn't find a standalone county ordinance for tiny homes. County rules for rental buildings reference state statute definitions of RVs and manufactured homes, and Montana has adopted Appendix Q (the tiny-home provisions of the state building code), so a foundation-built tiny home would likely go through standard county building permitting. RVs as full-time residences get murkier and probably depend on the zoning district.

Building permits. This is a "certified" building-code jurisdiction, meaning the county, not the state Building Codes Bureau, handles permitting and inspection locally through CDP. Statewide, there's sometimes an exemption for single-family homes from state permit jurisdiction, but that exemption applies where no local program exists, and here one does. Confirm current permit requirements and any exemptions directly with CDP.

Septic. This is where the county goes well beyond state minimums. Lewis and Clark's Environmental Health Division runs its own detailed On-Site Wastewater Treatment Regulations (adopted in 2016, updated in 2020), including an active septic maintenance and inspection program. Composting toilets and alternative systems would need to be sited and approved through this office.

Greywater and rainwater don't have dedicated county ordinances that I could find. Greywater is likely absorbed into the general onsite wastewater program; rainwater harvesting for personal, non-potable use doesn't appear restricted, but neither is explicitly confirmed.

Wells. Here's a real wrinkle: this county sits partly within Montana's "closed basins" (Upper Missouri, among others), where surface water was declared over-allocated decades ago. New water use, including some wells, may need to be "mitigated." Ordinary single-home exempt wells generally still go through DNRC's standard process, but the exempt-well statute itself is under legal challenge, with litigation filed in this county's district court. Check current status with DNRC's water rights office and loop in the county's sanitarian, who sits on state subdivision-sanitation review panels.

Utility disconnection. No ordinance explicitly bans living off-grid, but building, septic, and water approvals function as practical gatekeepers to legal occupancy.