Building permits, zoning and land rules in Powder River County, Montana

An ordinary single-family residence in unincorporated Powder River County is exempt from Montana's state building permit unless a local government has adopted its own permit requirement¹. Powder River County is not listed as a certified local building-code jurisdiction, so covered projects outside another certified local program go to the Montana State Building Codes Program². Farm and ranch buildings and qualifying private garages or storage buildings are also among the state exemptions².

Montana has adopted a uniform state building code for residential and commercial buildings, even though some projects are permit-exempt¹¹. A nonexempt building, alteration, addition, repair, move or change of occupancy in state jurisdiction requires a state permit before construction starts². State-permitted projects receive required inspections, and the permit holder must notify the inspector when work is ready³. Separate electrical, plumbing or mechanical permits may still apply even when a house itself is exempt from the building permit².

Powder River County is not a certified local building-code jurisdiction, so the Montana State Building Codes Program issues building permits and inspections for nonexempt work in areas under state jurisdiction^2,3.

Septic permits, subdivision review and county-road approvals do not come from the state building program; they stay with county offices. For land divisions, contact the Powder River County Planning Board at (406) 436-2361 or cgatlin@prco.mt.gov; its page provides preliminary-subdivision-plat and certificate-of-survey applications⁵. For onsite wastewater, contact the Powder River County Sanitarian at (406) 850-4544 or jtjuarez@gmail.com⁴. For work that encroaches on a county road, contact the Road Department at (406) 436-2248 or prcroad@prcomt.gov¹². The county road application says the Road Supervisor contacts the applicant within 7 days to arrange the required onsite inspection¹³. For development in a mapped flood hazard area, contact the Powder River County Floodplain Administrator at (406) 935-2242 or townofbroadus@rangeweb.net¹⁴.

We could not confirm a zoning ordinance for unincorporated Powder River County. The county's Planning Board materials list subdivision and survey applications but do not expressly say whether county zoning exists, so do not treat the lack of a published ordinance as permission for any use⁵. Ask the Planning Board about the parcel's current zoning status, setbacks, lot coverage and building-height rules before designing a project⁵.

The incorporated Town of Broadus is different: Broadus states that its zoning is set out in the Town Zoning Ordinance, and its Planning and Zoning Commission reviews proposed zoning amendments, site plans and plat applications⁶. We could not confirm a minimum dwelling size or minimum lot size for the unincorporated area, so ask the Planning Board rather than assuming there is no threshold⁵. Land divisions can still trigger Montana subdivision and surveying law¹⁵. An agricultural division outside a platted subdivision can avoid subdivision review only with a covenant restricting the divided land to agricultural use; changing to another use ordinarily triggers subdivision review¹⁶.

A Montana drainfield permit is required from the local health authority even when a property already has a state Certificate of Subdivision Approval⁷. In Powder River County, the County Sanitarian administers wastewater-treatment applications⁴. The published county application lists fees of $200 for a gravity system, $350 for pressure dose and an additional $200 for Level I review¹⁷. A permit lasts 12 months; a $50 fee continues it for another year, and the permit becomes void if the system is not installed within 24 months¹⁷.

Before backfilling, the applicant must give at least 24 hours' inspection notice or obtain preapproval for as-built documentation and photographs¹⁷. A site without DEQ approval needs professional site information that includes an 8-foot soil profile, a percolation test, groundwater information, water-quality results and a well log¹⁷. Only 12.9% of county soils are rated without severe limitations for a conventional drainfield, so make the septic evaluation a purchase contingency rather than assuming a standard system will work¹⁸.

We could not confirm a Powder River County rule that allows or prohibits long-term RV living on private land, temporary camping on private land, tiny-home occupancy or manufactured-home occupancy. County planning materials do not answer those questions, and countywide zoning itself remains unconfirmed⁵. Ask the Planning Board about land use and siting, then ask the County Sanitarian how wastewater must be handled before moving an RV or small dwelling onto a parcel^4,5.

The Montana camping limit for Fish, Wildlife & Parks public-use sites does not answer what is allowed on private rural property¹⁹. A tiny home used as a residence may fit the state permit exemption for a small residential building, but that building-permit exemption does not itself approve occupancy, septic, setbacks or use of the parcel². Inside Broadus, consult the town because its zoning ordinance applies independently of the unresolved countywide question⁶. On plumbing, Montana lets a homeowner skip the plumbing permit when installing the plumbing personally in a residence for personal use that is not built for resale or rental¹⁰.

1. Ask the Powder River County Planning Board whether the parcel is in unincorporated county territory, whether any county zoning applies, and whether a land division or survey review is needed⁵.
2. Confirm the building-permit path. A single-family residence in state jurisdiction is exempt unless a local government requires a permit, while nonexempt work in Powder River County goes through the Montana State Building Codes Program^1,2.
3. Apply to the County Sanitarian for the wastewater system, complete the required site work and arrange inspection before backfilling¹⁷.
4. For a new well, obtain a state water permit when use exceeds 35 gallons per minute or 10 acre-feet per year; a qualifying smaller well requires a Notice of Intent before use⁸.
5. Ask the local Floodplain Administrator whether the site is in a designated Special Flood Hazard Area and obtain a development permit when required⁹.
6. Apply to the Road Department if the work encroaches on a county road, or to the Montana Department of Transportation for a new or modified state-highway approach^13,20.

Start with septic feasibility and water. Only 12.9% of Powder River County soils are rated without severe limits for conventional drainfields, annual precipitation is about 15.6 inches, and severe drought occurs in 15.8% of years¹⁸. For groundwater use over 35 gallons per minute or 10 acre-feet per year, Montana requires a water permit; qualifying smaller developments follow the state's Notice of Intent process⁸.

Check legal access and flood exposure before closing. A county-road encroachment requires an application and onsite inspection, while a state-highway approach follows the state permit path^13,20. Development in a designated Special Flood Hazard Area requires a local floodplain permit⁹. Federal land accounts for 28.2% of the county, so verify that apparent map access is legal access and identify adjoining public ownership¹⁸. Finally, confirm whether the parcel is inside Broadus, where town zoning exists, or in the unincorporated county, where zoning remains unconfirmed^5,6.