On this page 6
§ 02
When a permit is required
Permit triggers and exempt work for Big Horn County
New construction of buildings, additions, alterations, repairs. State law exempts: farm/ranch buildings, mining buildings on mining property, residential buildings with fewer than 5 dwelling units (except transient), private garages and private storage buildings for owner's own use.
Farm or ranch buildings (not for human habitation or commercial use)
Mining buildings on mining property
Petroleum refineries and pulp/paper mills (except office/shop buildings)
Single-family residential buildings (fewer than 5 units, not serving transient guests) - exemption applies only in areas without certified local code enforcement
Private garages and storage buildings used solely for owner's own personal use (not commercial)
Certain agricultural buildings on classified agricultural land (requires Affidavit of Agricultural Exemption and approval letter from Montana Department of Revenue)
Minor repairs and maintenance
- Exempt Farm or ranch buildings (not for human habitation or commercial use)
- Exempt Mining buildings on mining property
- Exempt Petroleum refineries and pulp/paper mills (except office/shop buildings)
- Exempt Single-family residential buildings (fewer than 5 units, not serving transient guests) - exemption applies only in areas without certified local code enforcement
- Exempt Private garages and storage buildings used solely for owner's own personal use (not commercial)
- Exempt Certain agricultural buildings on classified agricultural land (requires Affidavit of Agricultural Exemption and approval letter from Montana Department of Revenue)
- Exempt Minor repairs and maintenance
Required documents
- Complete building permit/plan review application
- Construction plans and specifications prepared by licensed designer/engineer
- Site plan
- Structural calculations if required by code
- Electrical/plumbing/mechanical plans
- Building code
- Montana 2021 International Building Code (IBC) and International Residential Code (IRC); state has approved adoption of 2024 codes planned for mid-2026
- Permit validity
- Building permit is valid for the duration of construction but may expire if work does not commence within specified timeframe (typically 6-12 months, verify with state)
- Owner-builder
- Owner-builders may obtain permits for single-family dwellings on owner's own property; contact state Building Codes Program for specific requirements and restrictions
- Contractor requirements
- Electrical contractors must be licensed; plumbing contractors must be licensed; general contractors not required to be licensed at state level but check with county/local requirements
§ 03
Application process
Typical processing: Average 3 weeks for initial plan review if plans are complete; additional time may be required if revisions are needed
- 01 Review building code requirements and determine if permit is required
- 02 Prepare complete application with construction plans/drawings meeting IBC 2021 standards
- 03 Submit Building Permit/Plan Review Application and construction plans via EBIZ portal or mail to Montana Building Codes Program
- 04 Await plan review comments (approximately 2-3 weeks processing time)
- 05 Address any plan review comments and resubmit if required
- 06 Pay permit fee upon approval
- 07 Receive building permit and begin construction
- 08 Schedule inspections with state building inspector at least 24 hours in advance
- 09 Complete required inspections (foundation, framing, electrical, plumbing, mechanical, final)
- 10 Receive Certificate of Occupancy upon final inspection approval
Typical processing time: Average 3 weeks for initial plan review if plans are complete; additional time may be required if revisions are needed
Source: Montana Building Codes Program ↗
§ 04
Fee schedule
Big Horn County building permit fees
Fee type
Amount
01
Permit fee formula
Typically valuation-based percentage of total project cost, plus separate electrical/plumbing/mechanical permit fees
Payment required after plan approval and before permit issuance; accepted via EBIZ portal or mail. Contact (406) 841-2056 for current rates.
§ 05
Required inspections
Scheduling and sequence
How to schedule
- Permit holder must call state building inspector at least 24 hours in advance to schedule inspection (phone)
- Scheduling deadline
- 24 hours in advance
- Time windows
- Inspectors have 72 hours from notification to perform requested inspection
Typical sequence: Foundation, framing (before insulation), electrical rough-in, plumbing rough-in, mechanical rough-in, insulation, drywall, final inspection
§ 06
Frequently asked
Common questions about unincorporated Big Horn County permits
01 Do I need a building permit in unincorporated Big Horn County, MT? ▸
New construction of buildings, additions, alterations, repairs. State law exempts: farm/ranch buildings, mining buildings on mining property, residential buildings with fewer than 5 dwelling units (except transient), private garages and private storage buildings for owner's own use.
02 How much does a building permit cost in unincorporated Big Horn County, MT? ▸
Building permit fees in unincorporated Big Horn County, MT are set by the local building department and vary by project type and valuation. Fees are calculated as: Typically valuation-based percentage of total project cost, plus separate electrical/plumbing/mechanical permit fees.
03 How do I apply for a building permit in unincorporated Big Horn County, MT? ▸
To apply for a building permit in unincorporated Big Horn County, MT, follow these steps: 1. Review building code requirements and determine if permit is required 2. Prepare complete application with construction plans/drawings meeting IBC 2021 standards 3. Submit Building Permit/Plan Review Application and construction plans via EBIZ portal or mail to Montana Building Codes Program 4. Await plan review comments (approximately 2-3 weeks processing time) 5. Address any plan review comments and resubmit if required 6. Pay permit fee upon approval 7. Receive building permit and begin construction 8. Schedule inspections with state building inspector at least 24 hours in advance 9. Complete required inspections (foundation, framing, electrical, plumbing, mechanical, final) 10. Receive Certificate of Occupancy upon final inspection approval
04 How long does it take to get a building permit in unincorporated Big Horn County, MT? ▸
Building permit processing times in unincorporated Big Horn County, MT typically run Average 3 weeks for initial plan review if plans are complete; additional time may be required if revisions are needed. Timelines can vary based on project complexity and current department workload.
05 What work is exempt from building permits in unincorporated Big Horn County, MT? ▸
Not all construction work requires a permit in unincorporated Big Horn County, MT. The following work is generally exempt: Farm or ranch buildings (not for human habitation or commercial use); Mining buildings on mining property; Petroleum refineries and pulp/paper mills (except office/shop buildings); Single-family residential buildings (fewer than 5 units, not serving transient guests) - exemption applies only in areas without certified local code enforcement; Private garages and storage buildings used solely for owner's own personal use (not commercial); Certain agricultural buildings on classified agricultural land (requires Affidavit of Agricultural Exemption and approval letter from Montana Department of Revenue); Minor repairs and maintenance. When in doubt, confirm with the local building department before starting work.
06 How do I schedule a building inspection in unincorporated Big Horn County, MT? ▸
Once your permit is issued and work reaches an inspection milestone, you can schedule a building inspection in unincorporated Big Horn County, MT via: Permit holder must call state building inspector at least 24 hours in advance to schedule inspection. 24 hours in advance.
last verified March 2026
source Montana Building Codes Program ↗
entry id permits/montana/big-horn/unincorporated
Educational reference. Permit rules and fees change — confirm current requirements directly with Montana Building Codes Program before applying. Jaspector is not legal advice.