Unincorporated Granite County, Montana does not issue building permits for structures; the county has no building permit program1. County zoning approval is required only in the Georgetown Lake Zoning District, and septic permits for every property come from the Tri-County Sanitarian before construction1. A single-family residence also does not need a state building permit2.
Do you need a building permit in Granite County, Montana?
Granite County does not have a local building-code or building-permit program, and structures in unincorporated Granite County do not need a county building permit.
Granite County does not have a local building-code or building-permit program, and structures in unincorporated Granite County do not need a county building permit1. A single-family residence is also exempt from the state building permit unless a local government requires one2. Montana's Building Codes Program governs covered work where a county or town does not enforce codes, and certain state-jurisdiction projects may need a permit and inspections6,7. Farm and ranch buildings are exempt from the state building permit, but zoning, septic, trade, floodplain or subdivision requirements may remain7. Montana's 2024 International Building Code and International Residential Code, as amended by state rule, became effective September 26, 2026 where the state program applies8. Electrical and plumbing permits are separate requirements1.
Who handles building, zoning and septic permits in Granite County?
Granite County has no county building department issuing structural permits, so the Granite County Planning Department is the first call for parcel-specific land-use questions.
Granite County has no county building department issuing structural permits, so the Granite County Planning Department is the first call for parcel-specific land-use questions1. Planning oversees land divisions, zoning and floodplain administration1. Tri-County Environmental Health serves Granite County and handles septic-system permitting and licensing4,9. Required state-permit projects go through Montana's Building Codes Program and require notice to the inspector when work is ready7. The Granite County Commissioners issue encroachment permits for new, relocated or reconstructed driveways onto county roads, while the Road Department maintains county roads1,10. A connection to a state highway follows Montana's separate approach-permit process11.
Does Granite County, Montana have zoning?
Granite County zoning applies in designated areas rather than uniformly across the county; official findings identify the Rock Creek project area as unzoned.
Granite County zoning applies in designated areas rather than uniformly across the county; official findings identify the Rock Creek project area as unzoned3. The county publishes a map, ordinance and legal description for the Georgetown Lake Zoning District, including mapped neighborhood conservation districts and a lakefront subdistrict1. The Georgetown district has a 20-foot lakeshore protection setback12. Property in the Georgetown zoning area needs a zoning compliance permit before construction or dirt work, and a residential-to-commercial change of use needs approval before business activity begins1. The application requires sketches showing setbacks and structure height plus a $100 fee1. Granite County Planning Board conditions for one Rock Creek subdivision require 50-foot setbacks from property lines and Rock Creek, while its 1.88-acre and 3.74-acre lots do not establish countywide standards3. Ask Granite County Planning for the rules attached to the parcel1.
How do septic permits work in Granite County?
All Granite County properties must obtain a septic permit from the Tri-County Sanitarian before construction.
All Granite County properties must obtain a septic permit from the Tri-County Sanitarian before construction1. Tri-County Environmental Health serves Granite County and provides septic-system permitting and licensing4,9. Certified installers may self-inspect, while other inspection details depend on the installer and parcel4. A Montana Certificate of Subdivision Approval does not replace the local drainfield permit13. Only 2% of Granite County soils are rated without severe limits for a conventional drain field, so establish septic feasibility before fixing the house location14. Tri-County does not require a local well permit in Granite County, but a well using Montana's permit exception is limited to 35 gallons per minute and 10 acre-feet per year and requires state notices4,5.
Can you live in an RV or tiny home in Granite County?
A countywide rule for long-term residence in one private RV or for tiny-home occupancy could not be confirmed, so ask Granite County Planning about the parcel, zoning district and intended use.
A countywide rule for long-term residence in one private RV or for tiny-home occupancy could not be confirmed, so ask Granite County Planning about the parcel, zoning district and intended use1. Establishing more than one RV site for rental purposes is treated as a subdivision and requires subdivision review1. Granite County regulates new lots, including RV or mobile-home parcels, condominium units and townhomes1. More than five rental units on a property require review under the Granite County Rent and Lease Regulations, and rental units are not allowed in the Georgetown Lake Zoning District1. A primary structure offered through VRBO or Airbnb must be discussed with the Tri-County Sanitarian before listing1. A tiny home still faces any applicable septic, zoning, floodplain and access approvals even though Granite County does not issue a structural building permit1.
What are the steps to build a home in Granite County?
Ask Granite County Planning whether zoning applies to the parcel and whether the site lies in a floodplain.
- Ask Granite County Planning whether zoning applies to the parcel and whether the site lies in a floodplain1,3.
- Establish water and septic locations, then obtain the Tri-County septic permit before construction1,4.
- If Georgetown Lake zoning applies, submit the compliance application, setback-and-height sketches and the $100 fee before construction or dirt work1.
- Confirm electrical and plumbing permits, and determine whether the project needs a state building permit and inspections1,6,7.
- Obtain a Granite County encroachment permit before creating, relocating or reconstructing a driveway onto a county road1.
What should you check before buying Granite County land?
Start with septic feasibility: only 2% of Granite County soils are rated without severe limitations for a conventional drain field.
Start with septic feasibility: only 2% of Granite County soils are rated without severe limitations for a conventional drain field14. Check the parcel's mapped floodplain status because alterations such as grading, bank stabilization and construction require a floodplain permit in Granite County floodplains1. Confirm legal access and whether a county-road encroachment permit or a state-highway approach permit will be needed1,11. Recorded subdivision conditions can control setbacks even in an unzoned area, as the Rock Creek example shows3. Granite County is 69.5% wooded, 65.2% federally owned and only 22.7% gentle land, so parcel-level slope, wildfire exposure and adjoining ownership deserve close review14.
Watch-outs
- Granite County's lack of a county structural permit does not remove state-code jurisdiction or applicable septic, Georgetown Lake zoning, floodplain, electrical, plumbing and driveway requirements1,6.
- A general rule for one private RV, tiny-home occupancy, minimum dwelling size, minimum lot size and numeric setbacks could not be confirmed; ask Granite County Planning about the parcel and proposed use1.
- Only 2% of Granite County soils are rated without severe limitations for a conventional septic drain field, so septic feasibility can change the usable building area and budget14.
Sources
14 official pages, each quoted and re-checked · written October 9, 2026
- Planning Department
- bsd.dli.mt.gov
- Planning Department
- Planning Department | Granite County, MT
- Groundwater permit exceptions
- Montana Building Codes Program
- Building Permits
- Current Codes
- Tri-County Environmental Health (granitecountymt.gov)
- Granite County Road Department (granitecountymt.gov)
- Approach Manual for Landowners and Developers (Montana statewide rule)
- Montana Western Regional Hazard Mitigation Plan Addendum AA: Granite County
- Engineering Infrastructure & Subdivisions (Montana statewide rule)
- Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
Written October 9, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.
Off-grid gear
Going off-grid in Granite County means bringing your own water and power. The kit we’d start with:
- Water Crystal Quest Filter any source — well, rain, or creek — to drinking-clean.
- Power Bluetti Solar generators and home battery backup for living off the grid.
- Septic Soil percolation test kit Run your own perc test before paying an engineer — the first thing a septic office asks about.
- Water Well water test kit Bacteria, nitrates, hardness — know what the well on a parcel is really pumping.
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