Building permits, zoning and land rules in Broadwater County, Montana

In the parts of Broadwater County under Montana state jurisdiction, residential buildings with fewer than five dwelling units are exempt from state building permits unless they serve transient guests¹. Farm and ranch buildings are also exempt from the state building permit, but septic, floodplain, subdivision and other applicable rules remain in force¹. Owner-used private garages and storage buildings qualify only when they are not part of a business¹.

Montana adopts a uniform statewide building code; areas without a certified local enforcement program fall under the Montana Building Codes Program². Covered non-exempt buildings, additions, alterations, repairs and occupancy changes need a state permit before construction¹. Projects requiring that permit also require inspections, and the permit holder must notify the inspector and provide access when work is ready¹. Separate electrical, plumbing and mechanical permits may still apply³.

Broadwater County Community Development & Planning provides land-use guidance and property addressing from the county courthouse⁶. Reach the office at (406) 266-9211 or planning@broadwatercountymt.gov⁶. For covered building work under state jurisdiction, submit construction plans and a Building Permit/Plan Review Application to the Montana Building Codes Program¹.

State plan review averages about three weeks; the building permit is issued after review comments are satisfactorily answered in writing and fees are paid¹. Construction generally must wait for issuance; limited special arrangements may be available for footing or foundation work¹. The plan-review fee is 35% of the building-permit fee, and both must be paid before issuance⁹. Broadwater County Environmental Health handles septic permits countywide, including inside municipal limits, and requires a Planning Department address first⁴.

Broadwater County is reported as having subdivision regulations and a growth policy but no comprehensive county zoning outside incorporated areas⁵. Ask Community Development & Planning to confirm zoning for the exact unincorporated parcel⁶. Inside Townsend city limits, Townsend sets its own zoning; Broadwater County Environmental Health remains the septic-permit authority^4,10.

Broadwater County's subdivision regulations require review that may end in approval, conditional approval or denial¹¹. In multi-space mobile or manufactured-home parks created through subdivision, homes and attached structures must be at least 20 feet apart, pads must sit at least 10 feet from the serving street, and boundary setbacks also apply¹¹. Multi-space RV parks have separate spacing, boundary and parking standards¹¹. These park rules do not establish setbacks for a single home or RV on an ordinary private parcel¹¹. Development in a regulated flood hazard area generally requires a floodplain permit¹². General residential setbacks and minimum dwelling size could not be confirmed; ask Planning about the exact parcel⁶.

Broadwater County Environmental Health & Sanitarian handles local on-site wastewater permits⁴. For a parcel requiring a Broadwater County septic permit, obtain a Planning Department address before issuance and wait for the valid permit before dirt work, well drilling, foundations or related construction; starting early doubles the permit fee⁴. Reach Environmental Health at (406) 266-9209 or envhealth@broadwatercountymt.gov⁴.

The published application lists $250 with a certified installer, $350 with a non-certified installer and $100 for tank replacement only¹³. It also lists a $300 site evaluation when the property exceeds 20 acres or lacks a DEQ Certificate of Subdivision Approval¹³. A Certificate of Subdivision Approval does not replace the local drainfield permit¹⁴. Only 23.5% of county soils are rated without severe limits for a conventional drain field, so make septic feasibility a purchase contingency rather than assuming a conventional layout will work¹⁵.

Broadwater County's rules for living in an RV or tiny home on private land could not be confirmed; ask Community Development & Planning about the parcel, the proposed duration and whether the site is inside an incorporated municipality before moving in⁶. The reported absence of comprehensive county zoning outside incorporated areas is not, by itself, permission for residential occupancy⁵.

Montana's published camping-duration limits apply to Fish, Wildlife & Parks public-use sites, not private land¹⁶. Multi-space RV parks created through subdivisions have specific separation, boundary and parking standards, but those standards do not answer whether one household may occupy an RV on private land¹¹. Montana DEQ also reviews recreational camping-vehicle parks regardless of parcel size¹⁷. A tiny home may trigger septic, floodplain and trade-permit requirements depending on the site and work proposed^3,4,18.

1. Ask Community Development & Planning for land-use guidance and obtain the property address^4,6.
2. For a parcel requiring a septic permit, apply to Environmental Health and obtain issuance before dirt work, well drilling or foundation work begins⁴.
3. Ask whether the build site is in a regulated flood hazard area and obtain any required floodplain permit¹².
4. Determine whether the structure is state-permit exempt, which building-code program has jurisdiction, and which separate trade permits apply^1,3. A homeowner doing the plumbing personally may skip the state plumbing permit only when the residence is for personal use, not speculative resale or rental⁷.
5. For a covered state project, submit construction plans and the application, answer review comments in writing and pay the fees before building-permit issuance^1,9.
6. For access onto a county road, submit the county approach application and $125 fee before work⁸. A state-highway approach goes through the appropriate Montana Department of Transportation district office¹⁹.

Check septic feasibility first: only 23.5% of Broadwater County soils are rated without severe limits for a conventional drain field¹⁵. Confirm legal access and whether the driveway meets a county road or state highway, because those approaches use different permitting authorities^8,19. Check whether a regulated flood hazard area affects the build site¹².

For groundwater use no greater than 35 gallons per minute and 10 acre-feet per year, Montana provides a permit exception, but a Notice of Intent is required before use beginning in 2026; completion filings also apply²⁰. A subdivision inside a municipal or public sewer service area must install the required sewer facilities¹¹. Broadwater County averages 15.4 inches of precipitation annually and has experienced severe drought in about 13.2% of years, so verify the intended supply¹⁵. The median property-tax bill is about $2,210 a year¹⁵.