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

A home with fewer than five dwelling units in unincorporated Beaverhead County is exempt from the state building permit unless it serves transient guests¹. State building permits are required before certain other new construction, alterations, additions and repairs begin, and state-permitted work must be made available for required inspections¹.

Farm and ranch buildings are also exempt from the state building permit, but that exemption does not remove county wastewater, subdivision, floodplain or other land-use requirements¹. Separate electrical, plumbing or mechanical approvals may still apply to work exempt from the building permit, so confirm the full permit set with the Montana Building Codes Program before construction¹.

Beaverhead County is under the State Building Codes Bureau rather than a certified local building-code program, so the state issues building permits for covered construction in unincorporated areas¹. The permit holder must notify the state inspector when permitted work is ready and provide access for inspection¹.

Beaverhead County Land Use and Planning is the first county call for subdivision review, floodplain development and special land-use categories such as the Big Hole River area, Dillon Airport affected area, wireless facilities and buildings for rent or lease⁶. The county does not publish one process covering every land-use permit, so ask the office which application and supporting documents match the parcel and project⁶.

Beaverhead County has no general county zoning regulations, so there is no countywide rule on minimum dwelling size, building height or setbacks for an ordinary rural parcel³. That is not the same as no rules: landowners can petition for voluntary zoning districts, and the county's petition policy sets a $300 filing fee, so Land Use and Planning should confirm whether a particular parcel lies in one⁴. Subdivision regulations, floodplain rules and HOA covenants can also apply³.

Subdivision standards still matter. Commercial and industrial subdivisions and commercial lots within subdivisions need at least two acres, plus a 40-foot front setback and 50-foot side-yard setback⁷. Subdivision sites near rivers and other surface water have additional frontage, building and drain-field distances⁷.

Beaverhead County Environmental Health requires a wastewater permit before a new system is built or an existing system is repaired, replaced or altered². Off-grid occupancy does not avoid that rule: a regularly occupied structure producing wastewater must use a permitted individual or multi-user system unless a listed exception applies².

The system must be inspected before backfilling unless the department grants permission for the documented alternative using an as-built drawing, installation photos and installer verification². Inspection must be requested at least eight working hours before completion². Only 13.1% of mapped county soils lack severe limitations for a conventional drain field, so make wastewater feasibility an early purchase contingency⁸.

Beaverhead County's rule on long-term RV, tiny-home or manufactured-home occupancy on private land is not confirmed, so ask Land Use and Planning before placing a unit³. With no general county zoning, no countywide zoning rule is known to bar these uses on an ordinary parcel, but a petition-created zoning district, recorded subdivision covenants, floodplain regulation or a special-area permit could^4,6.

Wastewater is the firm requirement: a regularly occupied structure producing wastewater generally needs a permitted individual or multi-user system, and a new or altered system needs a county permit from Environmental Health². A tiny home serving transient guests may also fall outside the small-residential building-permit exemption¹.

1. Ask Land Use and Planning to screen the parcel for subdivision restrictions, a petition-created zoning district, floodplain status and special-area permits^4,6.
2. Confirm with the Montana Building Codes Program whether the project is exempt or needs state plan review, a building permit and inspections¹.
3. Obtain the county wastewater permit before septic construction and schedule inspection before backfilling².
4. For a new groundwater use, complete the applicable Montana water-right process; smaller uses may qualify for the permit exception but require a Notice of Intent before use⁵.
5. If access meets a county road, ask the Road Department about its approach permit⁹.

Start with wastewater feasibility because only 13.1% of mapped soils avoid severe conventional-drain-field limitations⁸. Confirm legal water: groundwater use of no more than 35 gallons per minute and 10 acre-feet per year may qualify for Montana's permit exception, but the state requires a Notice of Intent before use and combined wells can trigger a permit⁵.

Ask Land Use and Planning whether floodplain development or subdivision review applies; designated flood areas can require county permitting and no-build treatment during subdivision review⁶. A subdivision must complete county review and record its final plat before title is transferred, subject to the stated exceptions⁷. Current subdivision fees are available from the Clerk and Recorder and must be paid before the county acts⁷.