Bolthole Index

Carter County, Montana

Building permits, zoning and land rules in Carter County, Montana

49Index Score / 100
#44 of 56 in Montana

A building permit is not required for a single-family residence in unincorporated Carter County, Montana, unless a local ordinance or resolution requires one1. Montana still applies a statewide building-code framework, and covered projects follow the state permit process23. Every individual septic system requires approval from the Carter County Sanitarian4.

At a glance

Building permit
Not required for a single-family residence unless a local ordinance or resolution requires one1
Zoning
None; neither the county nor the Town of Ekalaka has zoning regulations5
Septic permit
Required; approved by the Carter County Sanitarian4
RV / tiny home on your own land
No zoning ordinance found; not officially confirmed either way5
Driveway onto a state highway
Needs an MDT approach permit before construction6
Well water
A permit exception may apply at 35 gallons per minute or less and no more than 10 acre-feet per year7
Property tax
About 0.4% effective rate; median bill about $782/year89

Who to call

Septic permits

Carter County Sanitarian

Approves individual septic systems in Carter County

406-436-2077

[email protected]

17 Ash Creek Rd, Olive, MT 59434

Also useful

Carter County Clerk & Recorder

Records deeds, plats and land records for Carter County; keeps septic-permit application forms on hand

406-775-8749

[email protected]

P.O. Box 315, Ekalaka, MT 59324

Also useful

Carter County Board of Commissioners

County governing body; the office to contact about floodplain status, road access and anything the county's website does not otherwise cover

406-775-8795

214 East Park Street, Ekalaka, MT 59324

Contact details are copied from each office’s official page and were checked against it on September 29, 2026.

Do you need a building permit in Carter County, Montana?

A building permit is not required for a single-family residence in unincorporated Carter County unless a local government requires one by ordinance or resolution1. Carter County's department directory lists no county building or inspection department, while the Town of Ekalaka issues building permits within town limits10. Montana has adopted a uniform statewide building-code framework, but cities, counties and towns may operate local enforcement programs only when certified2. For projects under state jurisdiction, farm and ranch buildings and residential buildings with fewer than five dwelling units are exempt unless they serve transient guests11. Covered projects may still need state building, plumbing, mechanical or electrical permits11.

Who handles permits and county business in Carter County, and how do you reach them?

Carter County has no building or zoning department, so land-use business in unincorporated Carter County runs through the courthouse in Ekalaka and the Carter County Sanitarian1213. The Carter County Sanitarian's office, which approves septic systems, is at 17 Ash Creek Rd, Olive, MT 59434, phone 406-436-207712. The Carter County Clerk & Recorder's office, which records deeds and plats and also keeps septic-permit application forms on hand, is at P.O. Box 315, Ekalaka, MT 59324, phone 406-775-874913. For anything else, the Carter County Board of Commissioners meets regularly at the courthouse and can be reached at 406-775-879514.

Does Carter County have zoning?

Neither Carter County nor the Town of Ekalaka has zoning regulations in place5. The one exception is airspace: the area around Ekalaka Airport is protected from obstructions under federal aviation rules, separate from any local zoning ordinance5. Montana law lets a county adopt zoning once its board of commissioners has adopted a growth policy, and Carter County has done exactly that with its own Growth Policy Update, but adopting a growth policy is not the same as adopting zoning regulations, and the county has not taken that second step155. No official source confirms an answer on setbacks, minimum lot size or where you can place an RV or tiny home, so treat those questions as unconfirmed rather than unrestricted, and check directly with the Board of County Commissioners before you plan a build14.

How do septic permits work in Carter County, Montana?

Every individual septic system in Carter County must be approved by the Carter County Sanitarian4. Montana DEQ reviews sanitation facilities for land divisions smaller than 20 acres and for condominiums, RV parks and mobile-home parks regardless of parcel size16. That review covers water supply, sewage disposal, solid waste and storm drainage17. A Certificate of Subdivision Approval does not replace the local drainfield permit18. About 32.7% of Carter County soils are rated without severe limits for a conventional drain field, but the Sanitarian must still evaluate the proposed system194.

Can you live in an RV or tiny home on your land in Carter County?

Whether you can live in an RV or tiny home on your own unincorporated Carter County land is not confirmed by an official county rule either way5. Neither Carter County nor the Town of Ekalaka has zoning regulations, but the absence of a zoning ordinance is not the same as an official answer, and no other Carter County source addresses RV or tiny-home occupancy directly5. A state rule limiting camping to 7 nights in any 30-day period applies only inside Montana Fish, Wildlife & Parks public-use sites, not to your own private land, so do not read it as Carter County's answer to full-time RV living20. Confirm your specific plan with the Board of County Commissioners before you commit14.

Building a home in Carter County: the steps, in order

  1. Confirm whether the project is an exempt single-family residence or a covered project that needs a state permit111.
  2. For a covered state project, submit construction plans and the Building Permit/Plan Review Application to the Montana Building Codes Program3.
  3. Contact the Carter County Sanitarian for septic approval; Montana DEQ also reviews covered subdivisions and developments smaller than 20 acres416.
  4. For a new well, determine whether a water-right permit is required; an exception may apply at 35 gallons per minute or less and no more than 10 acre-feet per year, with a Notice of Intent required before use beginning in 20267.
  5. Obtain an MDT approach permit or right-of-way agreement before building a new or modified driveway onto a state highway6.
  6. Ask the Board of County Commissioners whether the parcel is in a designated Special Flood Hazard Area and who handles the local floodplain permit2114.
  7. Record the deed, plat or survey with the Carter County Clerk & Recorder13.

What to check before you buy land in Carter County, Montana

Water deserves an early feasibility check in Carter County: annual precipitation averages 16.1 inches22. A groundwater development generally needs a water-right permit unless an exception applies; the stated exception threshold is 35 gallons per minute or less and no more than 10 acre-feet per year7. About 32.7% of county soils are rated without severe limits for a conventional drain field, so confirm the specific site with the Sanitarian1912. About 86.3% of Carter County land has a slope of 15% or less, while federal land covers about 28% of the county2324. The nearest metro area is about 195 miles away, so price utility, contractor and material logistics before closing25. Property taxes average an effective rate near 0.4%, with a median annual bill around $78289.

Watch-outs

  • Zoning, setbacks, minimum lot size and RV/tiny-home rules in unincorporated Carter County are not confirmed by any official county source; the absence of a zoning ordinance is not an official yes, so call the Board of County Commissioners before you rely on it514.
  • No Carter County floodplain administrator is named on the county's official website; confirm who holds that role and whether your parcel sits in a mapped flood zone before you build2114.
  • A Certificate of Subdivision Approval does not exempt you from a septic drainfield permit; Montana's own guidance says the local health department's permit is still required even with a COSA18.

Sources

  1. Building Permit FAQ, quoted and re-checked
  2. Montana Building Codes Program, quoted and re-checked
  3. Building Permits, quoted and re-checked
  4. Carter County Growth Policy Update, quoted and re-checked
  5. Carter County Growth Policy Update, quoted and re-checked
  6. Approach Manual for Landowners and Developers (Montana statewide rule), quoted and re-checked
  7. Apply for Water Rights, quoted and re-checked
  8. Effective property tax rate: Bolthole Index county data
  9. Median property tax bill: Bolthole Index county data
  10. Carter County, MT official website (Departments) (2026 county census)
  11. Building Permits (Montana statewide rule), quoted and re-checked
  12. Carter County Sanitarian (cartercountymt.gov)
  13. Carter County Clerk & Recorder (cartercountymt.gov)
  14. Carter County Board of Commissioners (cartercountymt.gov)
  15. 76-2-201. County zoning authorized, MCA (Montana statewide rule), quoted and re-checked
  16. Engineering Infrastructure & Subdivisions, quoted and re-checked
  17. Engineering Infrastructure & Subdivisions (Montana statewide rule), quoted and re-checked
  18. Engineering Infrastructure & Subdivisions (Montana statewide rule), quoted and re-checked
  19. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
  20. Public Use Rules and Regulations (Montana statewide rule), quoted and re-checked
  21. Stream Permitting (Montana statewide rule), quoted and re-checked
  22. Annual precipitation: Bolthole Index county data
  23. Share of land at 15% slope or less: Bolthole Index county data
  24. Federal land share: Bolthole Index county data
  25. Distance to the nearest metro area: Bolthole Index county data

Written September 29, 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

Carter County in Montana

49
County map
Carter County highlighted among the Montana counties · colored by Index score

How Carter County scores

Seclusion89100% ev.
Self-Sufficiency16100% ev.
Admin Boringness7690% ev.
Durability39100% ev.
Property Autonomy83100% ev.
Carry Cost8594% 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 →

$178kTypical home
0.4%Property tax
$753Land / acre
16.1"Annual rain
16.9% of yrsSevere drought
10.2 / yr (+8.3)Mid-century 100°F days
21.3 daysMid-century dry spell
1.05" (+5.2%)Mid-century 1-day rain
1.29×Wildfire change factor
100%Forward climate coverage
state median fallbackInsurance basis
156Radius comparison (15 mi)
0.4People / sq mi
28%Federal land
86.3%Land at 15% slope or less
32.7%Septic soil without severe limits
675,438 acWorkable land screen
3.8%Wooded land
13.7 tonsBiomass / forest ac
44.2°FAvg temp

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Answers from the rulebook for Carter County

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

Carter County rules

  • Zoning districtsNot published

    County and Town of Ekalaka zoning districts in Carter County.

    • The airspace around Ekalaka Airport is protected from obstructions under Title 14 Code of Federal Regulations, Part 77, Safe, Efficient Use, and Preservation of the Navigable Airspace.
    • Carter County subdivision regulations remain in place; floodplain regulations and other non-zoning rules may apply.
    “Neither Carter County nor the Town of Ekalaka have Zoning Regulations in place, although the airspace around Ekalaka Airport is protected from obstructions as required by Title 14 Code of Federal Regulations: Part 77 Safe, Efficient Use, and Preservation of the Navigable Airspace.”
  • Who permits septicMixed (with conditions)

    Individual septic systems and developments in Carter County, Montana.

    • Individual septic systems must be approved by the County Sanitarian.
    • The Carter County Sanitarian and Montana DEQ must review development with an area of less than 20 acres.
    • The source does not state that the Board of Health itself is the sole permitting authority.

    development area threshold: < 20 acres (Developments of 20 acres or more are not covered by this quoted review threshold.)

    “The Carter County Sanitarian and the Montana Department of Environmental Quality (DEQ) must review”
  • Septic permitRequired

    Individual septic systems in Carter County, Montana.

    • Approval by the County Sanitarian is required for individual septic systems.
    • The source separately states that Carter County Sanitarian and Montana DEQ review development with an area of less than 20 acres.
    • The source does not provide a permit form, fee, inspection timing, or exceptions beyond the stated development-size threshold.

    development area threshold: < 20 acres (The quoted review requirement is expressly for development with an area of less than 20 acres.)

    “a drainfield permit is still required by the local health department.”
  • County-wide zoningAbsent

    Carter County's official department listing shows no planning or zoning department, consistent with an unzoned rural ranching county.

    Carter County, MT official website (Departments) ↗Scouted from the county site, not yet independently re-checked

Montana rules that apply here

  • Building permitLimited

    Construction, remodeling, moving, alterations, additions, repairs, or changes of occupancy for buildings subject to Montana state building-code jurisdiction.

    • A state building permit is required before construction for certain types of new buildings and for certain alterations, additions, and repairs.
    • The state permit requirement does not apply to projects within the jurisdictional limits of a certified local government program; local requirements may apply there.
    • In the state's jurisdiction, state law exempts farm and ranch buildings; mining buildings on mining property; petroleum refineries and pulp and paper mills except office and shop buildings; residential buildings containing less than five dwelling units except when serving transient guests; and private garages and private storage buildings used for the owner's own use and not as part of a commercial enterprise or business.
    • Building permits must be issued on required projects before plumbing, mechanical, or electrical permits can be issued and before work authorized under those permits can start.
    “In Montana a state building permit is required prior to the start of construction for certain types of new buildings, and/or for alterations, additions, and repairs.”
    One more reviewed finding on this topic
    • Limited — Single-family residential construction under Montana state building-permit jurisdiction, including applicable unincorporated Carter County areas.
      “A building permit is not required for a single family residence, unless you live inside a local government's jurisdiction, which requires the permit by ordinance or resolution.”
  • Building code adoptedAdopted (with conditions)

    Montana's uniform state building code for residential and commercial buildings statewide.

    • The currently listed codes are amended and adopted through Administrative Rules of Montana Title 24, Chapter 301.
    • Cities, counties, and towns may enforce local building codes, all or in part, only through certified local building-code-enforcement programs.
    • State-owned agencies must be permitted through the Montana Department of Labor and Industry.
    • The listed 2021 International Building, Residential, and Existing Building Codes and related codes are effective June 11, 2022; the listed ASME boiler and pressure-vessel codes are effective November 6, 2021.

    International Building Code edition: 2021 · International Residential Code edition: 2021 · effective date for listed principal codes: 2022-06-11 (ASME boiler and pressure-vessel codes listed on the official page are effective 2021-11-06)

    “In addition, the program is responsible for adopting a uniform state building code, which is enforced statewide for residential and commercial buildings across Montana.”
    One more reviewed finding on this topic
    • Adopted (with conditions) — Montana statewide building-code framework, including Carter County areas not covered by a certified local enforcement program.
      “In addition, the program is responsible for adopting a uniform state building code, which is enforced statewide for residential and commercial buildings across Montana.”
  • InspectionsLimited

    Buildings and other projects requiring permits under Montana state building-code jurisdiction; certified local governments may perform inspections within their certified jurisdictional areas.

    • The Montana Building Codes Program performs inspections for projects requiring a permit under state jurisdiction.
    • The permit holder must notify the inspector when work is ready for inspection and provide access for required inspections.
    • Cities, counties, and towns may enforce local building codes and perform inspections only through certified local government programs; remaining areas fall under the state Building Codes Program.
    “The BC Program establishes and enforces statewide codes by issuing permits and performing inspections.”
  • Certificate of occupancyLimited

    Buildings constructed in accordance with the Montana state building code or a county, city, or town building code.

    • The certificate must certify that the building conforms to the applicable building regulations.
    • The statute addresses certificates for buildings constructed under the state or local building code; it does not establish a universal certificate requirement for every structure or every occupancy.
    “A certificate of occupancy for a building constructed in accordance with the provisions of the state building code or county, city, or town building code must certify that the building conforms to the requirements of the building regulations applicable to it.”
  • Well permitLimited

    New or expanded groundwater uses in Carter County and statewide Montana.

    • A permit is required unless an exception applies.
    • A groundwater development using 35 gallons per minute or less and not exceeding 10 acre-feet per year may qualify for a permit exception.
    • Beginning January 1, 2026, users relying on the exception must file a Notice of Intent before using the water.

    groundwater flow threshold: <= 35 gallons per minute (Permit exception may apply) · annual groundwater volume threshold: <= 10 acre-feet per year (Permit exception may apply)

    “A person is not required to apply for a permit to develop a groundwater well, spring, pit, or pond with a use of 35 gallons per minute or less, not to exceed 10 acre-feet per year (Section 85-2-306, MCA).”
  • Subdividing landRegulated (with conditions)

    Land divisions and qualifying condominiums, RV parks, and mobile-home parks in Carter County and statewide Montana.

    • DEQ review is limited to sanitation facilities, including water supply, sewage disposal, solid waste disposal, and storm drainage.
    • The cited threshold is divisions of land comprising less than 20 acres, plus listed facility types regardless of parcel size.

    land-division size: < 20 acres (RV and mobile-home parks are reviewed regardless of parcel size)

    “The DEQ Subdivision Program reviews divisions of land comprising less than 20 acres, as well as condominiums and recreational camping vehicle and mobile home parks, regardless of the size of the parcel where they are located.”
  • Driveway accessLimited

    New or modified driveway approaches intersecting Montana state highways, and changes in use of property abutting a state highway or an existing approach.

    • A new or modified approach requires either an approach permit or a right-of-way agreement.
    • A change in property use or change in use of an existing approach requires a new approach permit.
    • The landowner is responsible for obtaining the new permit.
    • The application must be made to the appropriate MDT District Office.
    • A detailed site plan and Environmental Checklist Form are required.
    • The requirement concerns state highways; local roads may be administered by local governments.
    “ALL NEW OR MODIFIED APPROACHES REQUIRE EITHER AN APPROACH PERMIT OR A RIGHT-OF-WAY AGREEMENT.”
  • Building in a floodplainRequired

    New development within a designated Special Flood Hazard Area in Montana.

    • The applicant must check with the local floodplain administrator to determine whether an SFHA has been designated.
    • Covered development includes placement of fill, roads, bridges, culverts, transmission lines, irrigation facilities, storage of equipment or materials, excavation, new construction or development, placement or replacement of manufactured homes, and new construction, additions, or substantial improvements to residential and commercial buildings.
    • Permit applications are obtained from the local floodplain administrator.
    • Application fees and timelines are established by the local government and vary widely throughout the state.
    “Anyone planning new development within a designated Special Flood Hazard Areas (SFHA).”
  • Short-term rentalsLimited

    Short-term rentals operated in Montana.

    • A Property Manager license is required unless the operator qualifies for an exemption under MCA § 37-56-104 or MCA § 50-51.
    • Local land-use, lodging, tax, and public-accommodation requirements may also apply.

    application fee: 50 USD

    “Short Term Rentals: A Property Manager license is required for short term rentals unless an operator qualifies for an exemption”
  • Permit feesVariable (with conditions)

    State building permit and plan-review fees for state-administered building permits.

    • The building permit fee is calculated by the bureau under IBC Section 109.2 as modified by ARM 24.301.138.
    • A plan review fee is charged in addition to the building permit fee and equals 35 percent of the building permit fee.
    • Both fees must be paid before the building permit is issued.
    • Local governments certified to enforce the state building code may establish their own permit fees and valuation method.

    plan review fee: 35 percent of building permit fee

    “The plan review fee is 35 percent of the building permit fee as established in Table 109.2.”
  • Permit processPublished (with conditions)

    State-administered Montana building permits for covered non-exempt construction outside certified local-government jurisdictions.

    • A state permit applies to certain new buildings and alterations, additions, and repairs.
    • Projects within the jurisdictional limits of a certified local government program are excluded from the state permit program.
    • Construction plans and a Building Permit/Plan Review Application must be submitted for review and approval.
    • The permit is issued after plan-review comments are satisfactorily answered and fees are paid.
    • Separate electrical, plumbing, and mechanical permits may be required.
    • The permit holder must notify the inspector when work is ready and provide access for required inspections.

    average plan review time: three weeks (Actual timing depends on workload, project size, and deficiencies.)

    “To obtain a state building permit, submit construction plans and a Building Permit/Plan Review Application to the Building Codes Program for review and approval.”
    One more reviewed finding on this topic
    • Partial — State building-permit process where Montana retains jurisdiction or a state permit is otherwise required.
      “To obtain a state building permit, submit construction plans and a Building Permit/Plan Review Application to the Building Codes Program for review and approval.”
  • Campground & park staysLimited

    Camping in Montana Fish, Wildlife & Parks public-use sites.

    • Camping is prohibited except in areas specifically designated or marked for camping.
    • A camping unit, vehicle, equipment, or personal items may not be left overnight without a person present.
    • Camping longer than 7 nights at one or more campsites in a public use area during any consecutive 30-day period is prohibited unless otherwise posted by the department.
    • Designated occupancy limits must not be exceeded.
    • Special-use-permit terms must be followed unless otherwise posted.
    • Campsites must be vacated by 1 p.m. on the day of departure; camping facilities must be vacated by 12 p.m. on the day of departure.

    maximum camping duration: <= 7 nights per consecutive 30-day period (unless otherwise posted by the department) · campsite departure time: 1 p.m. · camping-facility departure time: 12 p.m.

    “Unless otherwise posted by the department, within a public use site it is prohibited to: [...] camp at one or more campsites in a public use area for a period of longer than 7 nights during any consecutive 30-day period, beginning with the first night occupied unless otherwise posted by the department;”
  • county zoning authorityGeneral

    Montana boards of county commissioners adopting zoning regulations for all or parts of their jurisdictional areas, including unincorporated land.

    • The board of county commissioners must have adopted a growth policy pursuant to Montana Code Annotated chapter 1.
    • Zoning regulations must be adopted in accordance with Title 76, chapter 2.
    • The statute also contains a temporary provision for counties that adopted a master plan before October 1, 1999; that provision authorized adoption or revision only until October 1, 2006.
    “a board of county commissioners that has adopted a growth policy pursuant to chapter 1 is authorized to adopt zoning regulations”

Still unanswered

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

  • Owner-builder exemption — Owner-builders in Carter County.
  • Local zoning — Local zoning in Carter County, including incorporated and unincorporated areas.
  • Minimum dwelling size — Minimum dwelling size in Carter County.
  • Minimum lot size — Minimum lot size in Carter County.
  • Setbacks — Building and structure setbacks in Carter County.
10 more unanswered
  • Lot coverage
  • Building height
  • Living in an RV
  • Camping on your land
  • Tiny homes
  • Manufactured homes
  • Accessory dwellings
  • Septic inspection
  • Off-grid sanitation
  • Agricultural exemption

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 Carter County, Montana

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

Carter County scores 49/100 on the Bolthole Index, a solid county profile. Its strengths: deep seclusion — about 156 people within 15 miles and manageable long-term carry cost. Watch-outs: thin water margin (16.1″/yr rainfall) and elevated current hazard exposure.

Do you need a building permit in Carter County, Montana?

Carter County does not require a county building permit for a home in unincorporated areas, and it has no county-wide zoning. Onsite septic is permitted by Carter County Sanitarian. 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 Carter County, Montana?

Land in Carter County runs about $753 per acre, based on the latest county data.

What is the water situation in Carter County?

Carter County gets about 16.1" of rain a year, with severe drought in roughly 16.9% of years.

How remote is Carter County?

A typical private-land location has about 156 people within 15 miles and 201,456 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

Off-grid gear

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

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How Carter compares in Montana

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