Building permits, zoning and septic rules in Dawson County, Montana

An ordinary single-family home in unincorporated Dawson County is exempt from Montana’s state building permit¹. Dawson County has no county building-permit program, so owners may build their own home, though state licensing for electrical, plumbing and HVAC work may still apply¹. Nonexempt construction, alterations, additions and repairs need a state building permit before work begins, ahead of any plumbing, mechanical and electrical permits⁶. Farm and ranch buildings are exempt in state jurisdiction, but local requirements can still apply⁶. Construction in Dawson County’s zoned areas needs a separate Zoning Compliance Permit². Inside Richey, the Town’s building-and-construction application covers exterior projects involving Town rights-of-way or public property, including buildings, excavation, driveways, fences and decks¹². Septic drainfield permits remain separate through Dawson County Environmental Health^4,5.

Dawson County Planning handles subdivision review, zoning administration and floodplain administration at 406-377-3058, 207 W Bell St, Glendive, MT 59330³. Outside certified local building-code programs, the Montana State Building Codes Bureau has jurisdiction, subject to project exemptions; Montana’s 2024 International Building Code and International Residential Code took effect September 26, 2026¹³. State inspectors assigned around Montana perform the inspections the law requires; on a project needing a state building permit, the permit holder must notify the inspector when work is ready and provide access^14,15. Dawson County Environmental Health handles local septic questions at (406) 377-5213, 207 West Bell, Glendive, MT 59330⁵.

Most unincorporated Dawson County land is unzoned². The county’s zoning consists of two citizen-driven Part I districts, Highland Park and Forest Park, plus what its zoning page calls countywide Part II zoning². We could not confirm which parcels fall under Part II, so ask Dawson County Planning about a specific parcel³. Construction in any zoned area needs a Zoning Compliance Permit; the county’s application lists $75 for a building and $50 for a fence and states no different amounts by district⁷. Conditional-use or nonconforming projects need that approval first¹⁶. Outside the zoned areas, county zoning sets no minimum lot size, setback or dwelling floor area; other requirements can apply².

Highland Park R-HP single-family lots need 7,150 square feet and 65 feet of frontage¹⁰. Forest Park R-FP single-family lots need 7,200 square feet and 60 feet of frontage, with setbacks of 20 feet front, 5 side, 25 rear and 20 side-corner¹¹. Forest Park’s GC-FP commercial district lists 5,000 square feet and 50 feet of frontage for a single-family lot¹¹. Inside Glendive, the city’s separate zoning governs buildings and land uses¹⁷.

Septic permitting in Dawson County runs through the county's local health department, meaning the Sanitarian in Environmental Health, and a drainfield permit is required even if a Certificate of Subdivision Approval already exists for the property^4,5. Montana DEQ separately reviews sanitation facilities, including water supply, sewage disposal, solid waste and storm drainage, before parcels are created when land is divided into pieces under 20 acres, and for condominiums or recreational-vehicle and mobile-home parks regardless of size⁴. That DEQ review does not replace the local drainfield permit; both apply on a covered parcel⁴. Soils here are demanding: only 9.1% of Dawson County's land is free of severe limitations for a conventional drain field, so budget for a site evaluation and possibly an alternative system¹⁸. If your system discharges into state waters, a separate state groundwater or surface-water discharge permit can also apply¹⁹. For a well, spring, pit or pond, Montana doesn't require a groundwater permit as long as use stays at or below 35 gallons per minute and 10 acre-feet per year, though a Notice of Intent to Appropriate Groundwater, Form 602I, is required before putting water to use under that exception starting January 1, 2026⁸.

We could not confirm whether long-term RV or tiny-home occupancy is allowed on private rural land in Dawson County, so ask Dawson County Planning about the parcel and proposed dwelling³. Forest Park MF-FP permits qualifying manufactured or modular homes on permanent foundations; that rule does not establish permission for RV residences or tiny homes¹¹. On Montana state trust land in Dawson County, dispersed camping is limited to 2 consecutive days on leased or licensed land, or 16 days in a 30-day period on unleased or unlicensed land; those limits apply to trust-land recreation²⁰. Where county commissioners establish zoning under Montana’s county-zoning part, regulations must allow at least one accessory dwelling unit by right on a parcel containing a single-family dwelling, subject to applicable building, fire and public-health rules²¹.

1. Ask Dawson County Planning which zoning district covers the parcel and obtain a Zoning Compliance Permit if required^2,3.
2. Classify the project under state building-permit rules: ordinary single-family homes are exempt, while covered nonexempt projects require approval before construction^1,6.
3. Arrange required inspections for state-permitted work¹⁵.
4. Obtain the local drainfield permit from Environmental Health, even if the property already has subdivision sanitation approval^4,5.
5. Resolve road access and floodplain approval before site work: new or modified approaches onto state highways require an MDT approach permit or right-of-way agreement, and new development in a designated Special Flood Hazard Area requires a floodplain permit^22,23.

Dawson County averages 14.4 inches of precipitation annually and has experienced severe drought in 14.7% of years, so verify the parcel’s water source before purchase¹⁸. Only 9.1% of county soils are rated without severe limitations for a conventional septic drain field, making an early site evaluation valuable¹⁸. A land division exempt from Montana’s subdivision process can still require a survey and compliance with applicable zoning; the exemption cannot be used to evade subdivision law²⁴. For subdivision lots, physical access must meet applicable construction standards or approval conditions²⁵. A changed use of property or an existing approach abutting a state highway requires a new MDT approach permit²². Ask Dawson County Planning whether the parcel lies in a designated Special Flood Hazard Area requiring development approval^3,23.