Unincorporated Big Horn County, Wyoming requires a development permit before construction begins, but the county has not adopted a building code1. Land Planning reviews development applications for floodplain, airport-protection and septic issues; a separate floodplain development permit or septic permit may also be required1. Municipalities may set their own building and zoning requirements, while Big Horn County retains the development, subdivision and small-wastewater processes described here for unincorporated land1,2,3.
Do you need a building permit in Big Horn County, Wyoming?
Yes—rural and unincorporated Big Horn County requires a Development Permit Application and the applicable fee before construction begins.
Yes—rural and unincorporated Big Horn County requires a Development Permit Application and the applicable fee before construction begins1. The county publishes its permit process and links a fee schedule, although the amount depends on the application1,8. A development permit is not a conventional building-code permit: Big Horn County has not adopted building codes for unincorporated development, although applicable state electrical and fire-protection codes still govern1. Land Planning checks whether floodplain, airport-protection or septic permits also apply1. Projects inside a municipal boundary may face different municipal requirements, so contact the relevant town1.
Who is the Big Horn County building department, and who issues each permit?
Big Horn County Land Planning is the first call for rural construction and accepts development-permit applications.
Big Horn County Land Planning is the first call for rural construction and accepts development-permit applications1,9. Land Planning also administers septic permits for small wastewater systems, floodplain development permits for mapped hazard areas and subdivision applications on unincorporated land2. Big Horn County Engineering handles right-of-way permits for county-road work10. A new entrance intersecting a county road requires a right-of-way permit and onsite reviews before approval and after construction7. If utility service requires county-road right-of-way work, the provider submits the right-of-way application and fee; County Commissioners give final approval2. Inside a municipality, ask that municipality about its building permits and zoning; the county processes described above apply to unincorporated land1,2,3. Ordinary building inspections and certificates of occupancy could not be confirmed; ask Land Planning what project closeout is required.
Does Big Horn County have zoning?
Big Horn County does not have countywide zoning, but localized airport-protection zoning and special regulations in mapped flood zones still apply.
Big Horn County does not have countywide zoning, but localized airport-protection zoning and special regulations in mapped flood zones still apply4,5. Apart from special regulations in mapped flood zones and airport-protection zones, the county says it only requires permits for construction and development, subdivisions and small wastewater systems5. We could not confirm a county minimum dwelling size, minimum lot size, setback, lot-coverage or building-height rule, so ask Land Planning. The absence of countywide zoning does not remove the county development-permit, septic-permit or subdivision processes1,2,3. Unincorporated land divisions follow exemption, simple-subdivision or major-subdivision procedures; ask Land Planning which path applies because the county's summaries give inconsistent descriptions of a simple subdivision11. Municipalities may set different building-permit and zoning requirements inside their boundaries; Big Horn County's cited subdivision and small-wastewater authority is for unincorporated land1,2,3.
How do septic permits work in Big Horn County?
Big Horn County Land Planning administers permits for small wastewater systems in unincorporated Big Horn County.
Big Horn County Land Planning administers permits for small wastewater systems in unincorporated Big Horn County7. A system designed to discharge less than 2,000 gallons of domestic sewage per day falls within that county process7. Construction, installation, repair or modification requires an application, fee review and county permission before work begins7. The installer must leave the system uncovered until Land Planning visits and gives final approval7. Only 14.4% of county soils are rated without severe limits for a conventional septic drain field, so arrange site and soil work early rather than assuming a standard layout will fit12.
Can you live in an RV or tiny home in Big Horn County?
We could not confirm a county rule on RV, tiny-home or manufactured-home occupancy or temporary camping in unincorporated Big Horn County.
We could not confirm a county rule on RV, tiny-home or manufactured-home occupancy or temporary camping in unincorporated Big Horn County. The county states that, aside from mapped flood zones and airport-protection zones, it only requires permits for construction and development, subdivisions and small wastewater systems, so ask Land Planning before you move onto a parcel5. Other permits still apply: construction or development still requires a county development permit, and mapped flood zones or airport-protection zones can trigger additional review1,5. A tiny home or RV using a small wastewater system must follow the county septic process7. Big Horn County has not confirmed an ordinary building-inspection or certificate-of-occupancy requirement, so ask Land Planning what project closeout applies. Rules inside a municipality can differ from the unincorporated-county rules1.
How do you build a home in Big Horn County, step by step?
Confirm that the parcel is unincorporated and ask Land Planning about airport-protection and mapped flood-hazard constraints.
- Confirm that the parcel is unincorporated and ask Land Planning about airport-protection and mapped flood-hazard constraints1,5.
- If the purchase involves a land division, confirm whether it needs an exemption filing, simple-subdivision application or major-subdivision application before relying on the proposed parcel2.
- Submit the Development Permit Application and applicable fee before construction; consult the county's published fee schedule for the current charge1,8.
- If the site is in a mapped flood hazard area, submit a Floodplain Development Permit Application before excavation or construction13.
- Apply through Land Planning for a septic permit and wait for permission before installing, replacing or repairing the system2,7.
- Apply to the Wyoming State Engineer's Office for a well permit before drilling a domestic or stock well7.
- Obtain a right-of-way permit if new access or utility work enters a county-road right-of-way2,7.
- Keep the septic system exposed until Land Planning gives final approval7.
What should you check before buying land in Big Horn County?
Start with legal access: a new entrance intersecting a county road needs a right-of-way permit, while large parcels covered by the state subdivision rule generally need recorded access and utility easements to a public road.
Start with legal access: a new entrance intersecting a county road needs a right-of-way permit, while large parcels covered by the state subdivision rule generally need recorded access and utility easements to a public road7,14. Confirm that power, gas, water or telephone service can reach the site; county-road right-of-way work makes the provider responsible for a county permit2. Check flood maps because excavation or construction in a mapped flood hazard area requires a separate county application13. Test the septic area early because only 14.4% of county soils are rated without severe limits for a conventional drain field12. A domestic or stock groundwater well requires a permit before drilling7. Big Horn County averages 13.4 inches of precipitation annually, and severe drought has occurred in 16.8% of years, so verify a dependable water source12.
Watch-outs
- No countywide zoning does not erase development, septic, floodplain, airport-protection or subdivision requirements in Big Horn County1,5,7,11.
- Big Horn County has not confirmed ordinary building inspections or certificates of occupancy; ask Land Planning what closeout applies before starting work7.
- Inside a municipality, ask that municipality about building permits and zoning; Big Horn County's development, subdivision and small-wastewater processes described here apply to unincorporated land1,2,3.
Sources
14 official pages, each quoted and re-checked · written October 10, 2026
- Development Activities
- bighorncountywy.gov
- Septic Systems
- Planning & Zoning
- Planning & Zoning
- Startup Resources — Wyoming Business Council (Wyoming statewide rule)
- Land Planning FAQs
- Forms and Regulations
- Big Horn County Land Planning Office (bighorncountywy.gov)
- Big Horn County Engineering Office (bighorncountywy.gov)
- Subdivisions
- 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
- Floodplain Development
- Wyoming Statutes, Title 18 (Wyoming statewide rule)
Written October 10, 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 Big Horn 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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