How Propane Permits Work in Montana
Montana has the least regulated residential LP gas environment of the states covered in this guide. Most rural Montana counties have not adopted residential building codes. The state DLI licenses LP gas dealers, but local permit requirements are minimal or nonexistent in most of the state. Deep frost lines ranging from 36 inches in the south to over 60 inches at higher elevations must be considered for underground tank depth.
Before purchasing or leasing a propane tank in Montana: call your County building department or fire marshal's office and ask whether a permit is required for your specific tank size and installation type. Rules vary within Montana and are subject to change. This one phone call protects you.
State Agency Role: MT Dept. of Labor and Industry
DLI licensing; most counties have no building code. Even where no local building permit is required for an above-ground residential tank, the installation must be performed by an LP gas dealer or contractor licensed by this state agency. Verify your installer's license through the state agency's online lookup before signing a contract.
Permit Requirements by Installation Type
| Installation Type | Permit Required? | Who Issues | Typical Fee |
|---|---|---|---|
| Above-ground, under 125 gal | Verify locally | County building dept. or fire marshal | Often $0 or minimal |
| Above-ground, 125–500 gal | Commonly required | County building dept. or fire marshal | $25–$60 |
| Above-ground, 500+ gal | Required | County building dept. or fire marshal | $25–$60 |
| Underground, any size | Always required | County building dept. or fire marshal | Typically higher; verify |
| Gas piping (all sizes) | Almost always required | County building dept. | $25–$75 additional |
How to Find Your County's Specific Rules
- Step 1: Determine whether your property is inside a city/municipality (governed by city rules) or unincorporated County area (governed by County rules).
- Step 2: Search "[your County name] building department" to find the correct office and contact information.
- Step 3: Call and ask: "Do I need a permit to install a [size]-gallon [above-ground / underground] residential propane tank at [your address]?"
- Step 4: Ask about the gas piping permit separately — it is often required even when the tank permit is not.
- Step 5: Verify your installer's LP gas license with MT Dept. of Labor and Industry.
NFPA 58 Setback Requirements Apply Statewide
Whether or not a permit is required in your County, NFPA 58 setback requirements represent the minimum safe distances for LP gas tank placement. Use our Setback Calculator for your tank size, then verify whether your local AHJ has adopted any additional requirements beyond the national minimums.
Montana does not have a single statewide residential LP tank installation permit requirement applying uniformly to all properties. Permit authority rests with local County governments and municipalities. The state agency (MT Dept. of Labor and Industry) handles LP gas dealer and contractor licensing, not individual installation permits. Your specific requirements depend entirely on your County and whether your property is inside or outside city limits.
LP gas tank installations in Montana must be performed by an LP gas dealer or contractor licensed by MT Dept. of Labor and Industry. Homeowner self-installation is not permitted for tanks connected to a home's gas supply in most circumstances. Always ask for the installer's license number and verify it with the state agency before work begins.
It depends on whether your rural County has adopted a residential building code. Some rural Montana Countys have no residential building code, meaning no local permit is required for above-ground tanks. Others have adopted codes requiring permits. Underground tanks always require a permit regardless of location. Call your County to confirm which situation applies to your property.