Bolthole Index

Big Horn County, Wyoming

Building permits, zoning and land rules in Big Horn County, Wyoming

62Index Score / 100
#8 of 23 in Wyoming

Unincorporated Big Horn County, Wyoming requires a development permit before a construction project begins, but the county has not adopted building codes for development outside municipalities12. Land Planning reviews the application for floodplain, airport-protection and septic issues3. Small wastewater systems need a separate county septic permit4.

At a glance

Development permit
Required before construction in rural and unincorporated Big Horn County1
Building code
No county building code for development in unincorporated areas; state electrical and fire-protection codes still apply2
Zoning
No countywide zoning, but mapped flood zones and airport-protection zones have special rules5
Septic permit
Required through Big Horn County Land Planning for small wastewater systems64
RV / tiny home living
County occupancy rules were not confirmed; ask Land Planning before placing or occupying one51
Owner-builder
No building owner-builder exemption was confirmed; owners may install their own septic system under county guidance7
Water well
A state permit is required before drilling a domestic or stock well8
County-road access
New access intersecting a county road requires a right-of-way permit9

Who to call

Building permits

Big Horn County Land Planning Office

Development permits and review for floodplain, airport-protection and septic issues

307-568-2424

[email protected]

P.O. Box 29, 425 Murphy Street, Basin, WY 82410

Septic permits

Big Horn County Land Planning Office

Septic permit applications, construction authorization and final inspection for small wastewater systems

307-568-2424

[email protected]

P.O. Box 29, 425 Murphy Street, Basin, WY 82410

Floodplain permits

Big Horn County Land Planning Office

Floodplain development permit applications for mapped flood hazard areas in unincorporated Big Horn County

307-568-2424

[email protected]

P.O. Box 29, 425 Murphy Street, Basin, WY 82410

Roads & driveways

Big Horn County Engineering Office

Right-of-way permits for construction within county road rights-of-way

307-568-2467

[email protected]

P.O. Box 29, 425 Murphy Street, Basin, WY 82410

Contact details are copied from each office’s official page and were checked against it on September 27, 2026.

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 a construction project begins1. That development permit is not the same as a conventional building-code permit: Big Horn County has no building codes for development in unincorporated areas, although applicable state electrical and fire-protection codes still govern2. Land Planning uses the application to determine whether floodplain, airport-protection or septic permitting also applies3. Projects inside a municipal boundary may face municipal building codes, zoning or other requirements, so contact the relevant town instead of relying on the unincorporated-county rules10.

Who issues permits in Big Horn County, and how do you reach them?

Big Horn County Land Planning is the first call for a rural construction project and accepts development-permit applications111. The same office administers small-wastewater permits and floodplain development applications for affected unincorporated parcels1213. Big Horn County Engineering handles right-of-way permits for work within a county-road right-of-way14. A new access that intersects a county road requires a Right of Way Permit Application, an onsite review before approval and another onsite review after construction9. Building inspections and certificates of occupancy for ordinary development in unincorporated Big Horn County could not be confirmed; ask Land Planning what closeout, inspection or documentation applies to the particular project before work begins.

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 apply5. The county still requires permits for construction or development, subdivisions and small wastewater systems, so “no countywide zoning” does not mean no county review514. Municipalities may impose their own building codes, zoning or other requirements inside town boundaries10. The available county rules do not confirm a general minimum home size, residential setback, or minimum lot size for an ordinary existing parcel; ask Land Planning about the parcel and any airport or flood overlay before designing. If land will be divided, Big Horn County's subdivision process applies outside municipal boundaries, with the precise path depending on the division and any exemption15.

How do septic permits work in Big Horn County?

Big Horn County Land Planning administers permits for small wastewater systems in unincorporated Big Horn County616. The county defines that class as a system designed to discharge less than 2,000 gallons of domestic sewage per day16. Permission to install, repair or modify a system is withheld until Land Planning receives and reviews the application and fee4. After authorization, a property owner may use a contractor or install the system personally under Land Planning guidance7. The installer must leave the system uncovered until Land Planning visits the site and gives final approval17. Only 14.4% of county soils are rated without severe limits for a conventional septic drain field, so arrange the site and soil work early rather than assuming a standard layout will fit18.

Can you live in an RV or tiny home in Big Horn County?

Big Horn County has no countywide zoning, but that fact alone does not establish permission to live full-time in an RV or tiny home5. The available county rules do not confirm RV occupancy, tiny-home standards, a minimum dwelling size or a certificate-of-occupancy rule for unincorporated land; ask Big Horn County Land Planning about the proposed structure and use before purchase or placement. A construction or development project still requires a development permit, and mapped flood zones or airport-protection zones can trigger additional review15. A tiny home using an onsite wastewater system also must follow the county septic process4. Rules inside a municipality can differ from the unincorporated-county rules10.

Building a home in Big Horn County: the steps, in order

  1. Confirm whether the parcel is unincorporated and ask Land Planning to identify mapped floodplain or airport-protection constraints103.
  2. Submit the Development Permit Application and applicable fee to Land Planning before starting construction1.
  3. Apply through Land Planning for the septic permit and wait for permission before installing, repairing or modifying the system124.
  4. Apply to the Wyoming State Engineer's Office before drilling a domestic or stock well8.
  5. Obtain a right-of-way permit from Engineering if new access intersects a county road, and complete the required onsite reviews149.
  6. Keep the septic system exposed until Land Planning gives final approval17.

What should you check before buying land in Big Horn County?

Start with legal access: a new entrance intersecting a county road needs a county right-of-way permit, while large parcels covered by the state subdivision rule generally need recorded access and utility easements to a public road919. Check flood maps and airport-protection areas with Land Planning because either can add review to the development permit3. Test the proposed septic area early because only 14.4% of county soils are rated without severe limits for a conventional drain field18. Confirm the water plan too: a domestic or stock groundwater well requires a permit before drilling8. Big Horn County averages 13.4 inches of precipitation annually, and severe drought has occurred in 16.8% of years, making a dependable water source a practical due-diligence issue2021. The effective property-tax rate is about 0.6%, with a median annual bill of about $1,1562223.

Watch-outs

  • No countywide zoning does not erase development, septic, floodplain, airport-protection or subdivision requirements in Big Horn County514.
  • Big Horn County's published material does not confirm RV occupancy, tiny-home standards, ordinary building inspections, certificates of occupancy or a building owner-builder exemption; ask Land Planning before relying on any of those assumptions527.
  • Municipal building and zoning rules may differ from the unincorporated-county rules10.

Sources

  1. Development Activities, quoted and re-checked
  2. Land Planning FAQs, quoted and re-checked
  3. Development Activities (2026 county census)
  4. Land Planning FAQs, quoted and re-checked
  5. Planning & Zoning, quoted and re-checked
  6. Land Planning FAQs (2026 county census)
  7. (2026 county census)
  8. Land Planning FAQs, quoted and re-checked
  9. Land Planning FAQs, quoted and re-checked
  10. Planning & Zoning, quoted and re-checked
  11. Big Horn County Land Planning Office (bighorncountywy.gov)
  12. Big Horn County Land Planning Office (bighorncountywy.gov)
  13. Big Horn County Land Planning Office (bighorncountywy.gov)
  14. Big Horn County Engineering Office (bighorncountywy.gov)
  15. Subdivisions, quoted and re-checked
  16. Land Planning FAQs, quoted and re-checked
  17. Land Planning FAQs, quoted and re-checked
  18. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
  19. Wyoming Statutes, Title 18 (Wyoming statewide rule), quoted and re-checked
  20. Annual precipitation: Bolthole Index county data
  21. Share of years in severe drought: Bolthole Index county data
  22. Effective property tax rate: Bolthole Index county data
  23. Median property tax bill: Bolthole Index county data

Written September 27, 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.

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County locator

Big Horn County in Wyoming

62
County map
Big Horn County highlighted among the Wyoming counties · colored by Index score

How Big Horn County scores

Seclusion86100% ev.
Self-Sufficiency30100% ev.
Admin Boringness7490% ev.
Durability39100% ev.
Property Autonomy74100% ev.
Carry Cost87100% ev.

Evidence strength: 98%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$295kTypical home
0.6%Property tax
$2,313Land / acre
13.4"Annual rain
16.8% of yrsSevere drought
6.6 / yr (+5.9)Mid-century 100°F days
24.6 daysMid-century dry spell
0.9" (+6.3%)Mid-century 1-day rain
1.2×Wildfire change factor
100%Forward climate coverage
$1,365Home insurance / yr
2.7% / yrInsurance growth
0.6%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
46,523People within 2 hr
3,056Radius comparison (15 mi)
3.8People / sq mi
76.8%Federal land
62.7%Land at 15% slope or less
14.4%Septic soil without severe limits
246,518 acWorkable land screen
13.2%Wooded land
33 tonsBiomass / forest ac
43.3°FAvg temp

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Answers from the rulebook for Big Horn County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Big Horn County rules

  • Building permitRequired

    Construction projects in rural and unincorporated Big Horn County.

    • Before starting a project, submit a Development Permit Application and applicable fee to the Land Planning Department.
    • Additional floodplain, airport-protection, or septic permitting may be required depending on the project location and scope.
    “Before starting your project, you must complete a Development Permit Application and submit it (with the applicable fee) to the Land Planning Department.”
  • Building code adoptedNot adopted

    Building codes for development in unincorporated Big Horn County.

    • Construction must follow applicable state electrical and fire-protection codes.
    • The county recommends national building-code standards for improvement projects.
    • Municipal boundaries may have different requirements.
    “Big Horn County does not have any building codes for development in unincorporated areas.”
  • County-wide zoningAbsent

    Countywide zoning in Big Horn County.

    • The county states that localized airport-protection zoning and special regulations for mapped flood zones still apply.
    “Big Horn County does not have countywide zoning, only localized Aiport protection zoning.”
  • Local zoningVaries (with conditions)

    Aggregate local zoning across Big Horn County; the county has no countywide zoning, while incorporated municipalities may impose their own requirements.

    • Localized airport-protection zoning and mapped flood-zone regulations apply in specified areas.
    • Projects within municipal boundaries may be subject to municipal building codes, zoning, or other requirements.
    “If your project is within a municipal boundary, please contact the appropriate municipality before you start the work. They may have building codes, zoning or other requirements that differ from the unincorporated areas of the county.”
  • Who permits septicCounty (with conditions)

    Small wastewater systems in unincorporated Big Horn County.

    • The county Land Planning Department administers the county septic permit process.
    • The county process applies to small wastewater systems; the FAQ defines a small wastewater system as one designed to discharge less than 2,000 gallons of domestic sewage per day.

    domestic sewage flow threshold: < 2000 gallons per day

    “A septic permit is a written authorization issued by the county, which authorizes the applicant to construct, install, repair or modify a small wastewater system.”
  • Septic permitRequired

    Construction, installation, repair, or modification of small wastewater systems in unincorporated Big Horn County.

    • Permission to install, repair, or modify is not granted until the application and fee are received and reviewed.
    • The installer may begin only after permission to construct is given.

    small wastewater threshold: < 2000 gallons per day

    “Permission to install, repair or modify a system will not be granted until the applicant’s application and fee have been received and reviewed by the Land Planning Department.”
  • Septic inspectionRequired

    Small wastewater system installation in unincorporated Big Horn County.

    • The system must be inspected before backfilling.
    • Final county approval is required before backfilling.
    “The installer cannot backfill until the Land Planning Department has visited the site and given final approval of the system.”
  • Mandatory utility hookupConditional

    New utility service requiring work in a county-road right-of-way.

    • Contact the local utility provider for service.
    • The provider must submit a Right of Way Permit Application and fee to the Engineering Department if establishing service requires work in a county-road right-of-way.
    • After review, the application goes to the County Commissioners for final permit approval.
    “The provider is required to submit a Right of Way Permit Application and fee to the Engineering Department if the establishment of any new service will require any work in the right-of-way of a county road.”
  • Subdividing landRegulated (with conditions)

    Land divisions and subdivisions outside municipal boundaries in Big Horn County.

    • Exempt subdivisions require an Affidavit of Exemption.
    • Family-exemption requirements differ for filings on or before February 26, 2019 and filings on or after February 27, 2019.
    • A simple subdivision is one unit divided into one or two lots smaller than 35 acres; the county page also describes a simple subdivision as one or up to five lots smaller than 35 acres, so the applicable regulation should be consulted.
    • Major subdivisions include divisions into three or more lots, each smaller than 35 acres, and subdivisions not qualifying as simple subdivisions.
    • Applications are submitted to the Land Planning Department; municipal properties should be referred to the municipality.

    lot-size threshold: < 35 acres (Parcels greater than or equal to 35 acres created as part of a land division are exempt from the subdivision process.) · family exemption grantor ownership period: >= 10 years (Applies to filings on or after 2019-02-27; earlier filings use the prior 5-year requirement.)

    “The Big Horn County Subdivision Regulations were modeled directly from the Wyoming State Statutes, Title 18, Chapter 5, Article 3 and customized to meet the specific needs of our county. They were amended on January 18, 2022.”
  • Driveway accessRequired

    New access intersecting a county road in Big Horn County.

    • A Right of Way Permit Application is required for newly constructed access intersecting a county road.
    • An onsite review is required before approval and another onsite review follows construction.
    • The permit is approved when the County Engineer and County Commissioners sign the application.
    “If the access you are requesting will be newly constructed and intersects any county road, you will need to complete a Right of Way Permit Application through the Engineering Department.”

Wyoming rules that apply here

  • Well permitRequired

    Construction of a groundwater well or development of a spring in Wyoming, including domestic and stock wells or springs flowing at most 25 gallons per minute.

    • An approved permit must be received before drilling or spring-development activities begin.
    • Springs flowing more than 25 gallons per minute, or springs used for purposes other than domestic or stock watering, must be permitted through the Surface Water Division.
    • Wells must be drilled by a Wyoming licensed water-well drilling contractor and pumps must be installed by a Wyoming licensed pump-installation contractor.
    • The U.W. 5 application must be complete and accurate and accompanied by the appropriate filing fee.
    • Domestic and stock applications are listed with a $50 filing fee.

    spring flow threshold: <= 25 gallons per minute (Higher-flow springs or non-domestic/non-stock use are handled through the Surface Water Division.) · domestic permit filing fee: 50 USD · stock permit filing fee: 50 USD

    “Wells and Springs - Before you drill a well, or develop a spring* (that flows less than or equal to 25 gallons per minute (gpm) and will be used f or D omestic and/or Stock W atering use only), you must submit an "Application for Permit to Appropriate Ground Water", or U.W. 5 Form, to the Ground Water Division and receive an approved permit prior to commencement of any drilling or spring development activities.”
    One more reviewed finding on this topic
    • Required — Domestic and stock groundwater wells in Big Horn County.
      “Before you drill a well that will be used for domestic and/or stock use, you must submit an application for a permit to the Wyoming State Engineer’s Office (SEO), Ground Water Division.”
  • Agricultural exemptionAvailable (with conditions)

    Certain land divisions for agricultural purposes under Wyoming's Real Estate Subdivisions Act, primarily in unincorporated areas subject to county administration.

    • The exemption applies unless the method of sale or other disposition is adopted for the purpose of evading the Act.
    • The division must be a sale or other disposition of land for agricultural purposes or affect the alignment of property lines for agricultural purposes.
    • The exempt divisions remain subject to county-board requirements regarding documentation of proper use and implementation of the exemption.
    • A division for an immediate family member has separate conditions, including qualifying family relationship, housing, business, or agricultural purpose, ownership and titling periods, and a five-acre further-division restriction; that family exemption is distinct from the agricultural-purpose exemption.
    • For parcels 35 acres or larger, ingress, egress, and utility easements of at least 40 feet to a public road are required unless specifically waived by the grantee or transferee in a binding and recordable document.

    large-parcel threshold: >= 35 acres (Subject to W.S. 18-5-316 and required easements.) · large-parcel easement width: >= 40 feet (To a public road; waiver must be binding and recordable.)

    “A division which is a sale or other disposition of land for agricultural purposes or affects the alignment of property lines for agricultural purposes;”
  • Building in a floodplainRequired

    Building within the floodplain in Wyoming communities participating in the state-supported National Flood Insurance Program floodplain-management program.

    • The source states that Wyoming currently has 19 participating counties and 66 participating municipalities.
    • Enrollment and participation require a community letter of resolution, an application form, a permitting process, and a compliant ordinance adopted.
    • The permit must meet minimum standards set forth in the applicable local ordinance.
    • The source describes state technical assistance and oversight, while the local ordinance supplies the applicable minimum standards.

    participating counties: 19 counties · participating municipalities: 66 municipalities

    “Currently in Wyoming, there are 19 participating counties and 66 participating municipalities. Enrollment and participation in the program requires a letter of resolution by the community, an application form, a permitting process, and a compliant ordinance adopted. Building within the floodplain requires a permit, and must meet minimum standards set forth in the local ordinance.”
  • Permit processPublished (with conditions)

    Subdivision activity subject to Wyoming Statutes Title 18, Article 5.

    • The requirement applies to land subject to subdivision regulation under the cited article.
    • The permit is obtained from the board of the county in which the land is located.
    • The statute cross-references W.S. 18-5-306 and, if applicable, W.S. 18-5-316.
    • Each board must enforce the article and adopt rules and regulations necessary to implement it.
    “No person shall sell land subject to subdivision regulation under this article, record a plat or commence construction of a subdivision without first obtaining a subdivision permit pursuant to W.S. 18-5-306 or, if applicable, W.S. 18-5-316 from the board of the county in which the land is located.”
  • county zoning authorityGeneral

    County regulation of the location and use of buildings and structures and the use, condition of use or occupancy of land in unincorporated areas of Wyoming.

    • The authority is exercised by each board of county commissioners for the unincorporated area of the county.
    • County zoning may not contravene the zoning authority of an incorporated city or town.
    • A zoning resolution or plan may not prevent a use or occupancy reasonably necessary for extraction or production of mineral resources.
    • A board may not require land use or physical development to be consistent with a local land use plan unless the applicable plan provisions have been incorporated into local zoning regulations.
    • Minimum lot size requirements or other zoning measures may not prevent residential or agricultural uses authorized for land divisions exempt from subdivision requirements under W.S. 18-5-303(a)(i).
    • Private schools meeting the statutory requirements may not be regulated differently from public schools: certification by the professional engineer or architect of record, capacity for fifty (50) students or more, and ownership and operation by a not-for-profit entity.
    “To promote the public health, safety, morals and general welfare of the county, each board of county commissioners may regulate and restrict the location and use of buildings and structures and the use, condition of use or occupancy of lands for residence, recreation, agriculture, industry, commerce, public use and other purposes in the unincorporated area of the county.”
  • county building authorityLimited

    County enforcement and interpretation of local or state fire, building, existing-building, and electrical safety standards, including residential construction in unincorporated areas, when the county obtains local enforcement authority under W.S. 35-9-121.

    • A county must apply for local enforcement authority and receive delegation from the state fire marshal by letter.
    • Before initial delegation, the state fire marshal must determine that the county has adopted minimum standards by ordinance or resolution equivalent to or more stringent than applicable department standards.
    • If the county fails to adopt new standards within six (6) months after department adoption, or fails to maintain standards at least meeting statewide standards, enforcement authority immediately reverts to the department.
    • For fire and building code enforcement, inspectors employed or contracted after July 1, 2010 must be certified by the International Code Council or the International Conference of Building Officials.
    • If electrical-code authority is requested, an electrical inspector must be certified by the International Code Council or International Association of Electrical Inspectors and licensed by Wyoming as a journeyman or master electrician.
    • If the county fails to maintain a required certified inspector, enforcement authority reverts to the department one hundred twenty (120) days after the inspector leaves.
    • A local governmental entity may assume sole plan-review authority and sole construction-inspection authority on approved plans, subject to the statutory certification requirements.
    • If local code provisions are more stringent than adopted state codes, the local code prevails.
    • The statute grants authority to enforce and interpret building standards; it does not establish that every Wyoming county universally requires a residential building permit without county-specific implementation.

    new standards adoption deadline: 6 months (following adoption of new standards by the department) · certification applicability date: July 1, 2010 (inspectors employed or contracted after this date) · authority reversion period after certified inspector leaves: 120 days

    “The state fire marshal shall delegate complete authority to municipalities and counties which apply to enforce and interpret local or state fire, building, existing building standards or electrical safety standards which meet the requirements of this section. The state fire marshal shall notify the governing body of the municipality or county of the minimum standards and requirements of this act and W.S. 16-6-501 and 16-6-502 and transfer jurisdiction and authority by letter.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

  • Owner-builder exemption — Owner-builder exemptions for construction in unincorporated Big Horn County.
  • Inspections — Building inspections in unincorporated Big Horn County.
  • Certificate of occupancy — Certificates of occupancy in unincorporated Big Horn County.
  • Short-term rentals — Short-term rentals in unincorporated Big Horn County.

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Living off-grid in Big Horn County, Wyoming

Is Big Horn County a good place to live off-grid or homestead?

Big Horn County scores 62/100 on the Bolthole Index, a solid county profile. Its strengths: manageable long-term carry cost and deep seclusion — about 3,056 people within 15 miles. Watch-outs: weak self-sufficiency basics: only 13.4″ of rain a year and elevated current hazard exposure.

Do you need a building permit in Big Horn County, Wyoming?

Big Horn County generally requires a residential building permit, and it has no county-wide zoning. Onsite septic is permitted by Big Horn County Land Planning Department (small wastewater systems, delegated under WY DEQ). These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

How much does land cost in Big Horn County, Wyoming?

Land in Big Horn County runs about $2,313 per acre, based on the latest county data.

What is the water situation in Big Horn County?

Big Horn County gets about 13.4" of rain a year, with severe drought in roughly 16.8% of years.

How remote is Big Horn County?

A typical private-land location has about 3,056 people within 15 miles and 245,209 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

Off-grid gear

Going off-grid in Big Horn County means bringing your own water and power. The kit we’d start with:

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How Big Horn compares in Wyoming

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