Bolthole Index

Yellowstone County, Montana

Building permits, zoning and septic rules in Yellowstone County, Montana

55Index Score / 100
#35 of 56 in Montana

Yellowstone County, Montana does not issue building permits or certificates of occupancy for structures outside the city limits of Billings.1 Zoning in unincorporated Yellowstone County runs through the joint City-County Planning Division, while Billings, Broadview and Laurel have their own zoning layers.23 Septic permits for every address come from RiverStone Health, not from the county commissioners or the zoning office.4 Only about 19.1% of the county's soils are rated free of severe limits for a conventional drain field, so plan for a site evaluation.5

At a glance

Building permit
Not required outside Billings city limits for a single-family home6
Zoning
Yes, countywide, via the joint City/County Planning Division and Zoning Commission7
Septic permit
Issued by RiverStone Health (local health department), not the county8
Owner-builder exemption
Montana does not restrict owner-builders from constructing their own single-family home9
Subdivision review
Parcels under 20 acres go through Montana DEQ; 20 acres or more go through local review8
Septic soils
About 19.1% of soils are free of severe limits for a conventional drain field5
Floodplain permit
Required for new development in a mapped Special Flood Hazard Area10

Who to call

Zoning

City-County Planning Division (Yellowstone County / City of Billings)

Zoning permits, zoning changes, variances, special use permits and subdivision applications for unincorporated Yellowstone County

(406) 657-8247

316 N. 26th Street, Billings, MT 59101

Online permits →

Septic permits

RiverStone Health, Environmental Health Services

Septic (on-site wastewater) permits and subdivision sanitation review for Yellowstone County

406.256.2770

123 South 27th Street, Billings, MT 59101

Floodplain permits

Yellowstone County Floodplain Administration (Public Works)

Floodplain permits and floodplain determinations for unincorporated Yellowstone County

406-256-2735

pubworks@yellowstonecountymt.gov

Online permits →

Contact details are copied from each office’s official page and were checked against it on October 9, 2026.

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

Not from the county, for a structure outside the city limits of Billings: Yellowstone County does not issue building permits or certificates of occupancy there.1 Inside Billings, the city's permit rules apply, and the county notice says outside structures are not subject to the same restrictions.1 Montana law also exempts residential buildings with fewer than five dwelling units, farm and ranch buildings, and private garages and storage buildings from the state building permit in areas outside certified cities, though separate electrical, plumbing or mechanical permits may still apply.11 Skipping a building permit does not skip the other approvals: unincorporated land still needs a zoning permit from the Planning Division, a septic permit from RiverStone Health if there is no sewer, a driveway approach permit where access meets a county road, and a floodplain permit if the parcel is in a mapped flood zone.2121314

Who handles zoning, septic, floodplain and driveway permits in Yellowstone County?

Zoning for unincorporated Yellowstone County runs through the City-County Planning Division, a joint agency with the City of Billings, at (406) 657-8247, 316 N. 26th Street, Billings, MT 59101, or through its CityView online portal.2 The division "provides community planning and development services to Yellowstone County, the City of Billings, and the Town of Broadview."2 Floodplain permits and determinations come from Yellowstone County's Floodplain Administration (Public Works) at 406-256-2735 or pubworks@yellowstonecountymt.gov.14 The Public Works Department also issues approach permits for driveways onto county-managed roads; construction may not begin until the permit issues, and a residential access permit is $75.1315 Septic permits come from RiverStone Health Environmental Health Services at 406.256.2770, 123 South 27th Street, Billings, MT 59101.12

Does Yellowstone County have zoning?

Yes. Unincorporated Yellowstone County has a County Zoning Code and Zoning Regulations, administered with the City-County Planning Division and the Zoning Commission.162 The county's map service shows separate Billings, Broadview and Laurel zoning layers, so a parcel inside one of those towns follows that town's zoning, not the county's.173 The Planning Division reviews "proposed projects and processing subdivision applications, applications for requests for zoning changes and variances, and special use permits" for the county.2 We could not confirm district-by-district lot sizes, setbacks or height limits from the county's zoning code, so ask the Planning Division which district covers the parcel before you buy or build.16

How do septic permits work in Yellowstone County?

Septic systems in Yellowstone County are permitted by RiverStone Health, not the county government.4 The review path depends on lot size: parcels under 20 acres go through the Montana Department of Environmental Quality review, and parcels of 20 acres or more go through local review.4 Before RiverStone Health reviews the lot, the applicant obtains a Permit Tracking Sheet from the Yellowstone County Courthouse, Room 305, which verifies an assigned address, an issued approach permit, and that the property is not in a floodplain.1812 The application also needs a detailed lot layout, the required fee and, for a residence, the bedroom count.18 New and repaired systems must be inspected and permitted before use, so call 406.256.2770 at installation to schedule the inspection.19 Only about 19.1% of the county's soils are rated free of severe limits for a conventional drain field, so budget for a site evaluation.5

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

We could not confirm a specific county rule for RV or tiny-home living on a private unincorporated lot, because the zoning code's use and dimensional standards were not available to us; ask the City-County Planning Division which district covers your parcel and whether it allows RV or manufactured-home occupancy.216 Where a county has established zoning, Montana law requires that zoning to allow at least one accessory dwelling unit by right on a lot with a single-family dwelling, attached, detached or internal, with a one-time review fee of up to $250.20 Building codes, fire codes and health rules, including septic, still apply to that unit.20 Montana's camping limits of 7 nights per 30-day period apply to Fish, Wildlife & Parks public-use sites, not to your own land.21

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

  1. Confirm with the City-County Planning Division that your parcel is outside Billings, Broadview and Laurel and that its zoning district allows the home you plan to build.23
  2. Ask the Floodplain Office, using the parcel's legal description, whether a floodplain permit is needed; a non-refundable $50 fee applies to each permit or variance application.2214
  3. For a driveway onto a county road, get an approach permit from Public Works before building it; for a state highway, apply to the Montana Department of Transportation.1323
  4. Obtain a Permit Tracking Sheet from the Yellowstone County Courthouse, Room 305.1812
  5. Submit the tracking sheet, lot layout, fee and bedroom count to RiverStone Health for septic approval.18
  6. Build; no county building permit applies outside Billings, but ask about state electrical, plumbing and mechanical permits.111
  7. Call RiverStone Health to schedule the septic inspection before the system is placed into use.19

What should you check before buying land in Yellowstone County?

Confirm your parcel's zoning district and any use restrictions with the City-County Planning Division, since the county has zoning even though it skips a county building permit.2161 Check with the Floodplain Administration whether the parcel sits in a mapped Special Flood Hazard Area; Yellowstone County is currently updating its floodplain regulations, so ask what's changing before you close.14 Budget for septic due diligence: with only about 19.1% of soils rated free of severe limits for a conventional drain field, a site evaluation should come before you finalize your build plan.5 The county gets only about 14.6 inches of precipitation a year and sees severe drought in roughly 12.3% of years, so plan your water supply and any well with that dryness in mind.2425 Typical property tax runs about a 0.8% effective rate with a median bill near $2,669 a year, and a typical homeowner's insurance premium runs closer to $2,302 a year, both worth building into your budget.262728

Watch-outs

  • Yellowstone County is currently updating its floodplain regulations and is taking public comment through its Public Works floodplain contact; confirm which rules apply to your parcel before you buy or build near a flood-prone area.14
  • Skipping a county building permit does not skip zoning, septic, driveway approach or floodplain review in Yellowstone County; confirm each separately before you build.11316
  • Septic review differs by lot size: parcels under 20 acres go through Montana DEQ, while parcels of 20 acres or more go through RiverStone Health's local review process.4
  • The septic permit tracking sheet requires an approach permit to have been issued first, so apply for the driveway approach before the septic application.29

Sources

  1. Yellowstone County Public Works General Information, quoted and re-checked
  2. City-County Planning Division (Yellowstone County / City of Billings) (billingsmt.gov)
  3. Yellowstone County Zoning MapServer, quoted and re-checked
  4. Septic Permits + Subdivision Review, quoted and re-checked
  5. 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
  6. Yellowstone County Public Works Permits (2026 county census)
  7. Yellowstone County Board of Commissioners Minutes, April 1, 2025 (2026 county census)
  8. RiverStone Health - Septic Permits & Subdivision Review (2026 county census)
  9. Yellowstone County Public Works General Information (2026 county census)
  10. Stream Permitting (Montana statewide rule), quoted and re-checked
  11. Is a State Building Permit Needed?, quoted and re-checked
  12. RiverStone Health, Environmental Health Services (riverstonehealth.org)
  13. Yellowstone County Road Policies, quoted and re-checked
  14. Yellowstone County Floodplain Administration (Public Works) (yellowstonecountymt.gov)
  15. yellowstonecountymt.gov, quoted and re-checked
  16. Yellowstone County Board of Commissioners Minutes, April 1, 2025, quoted and re-checked
  17. Yellowstone County Zoning MapServer, quoted and re-checked
  18. Septic Permits + Subdivision Review, quoted and re-checked
  19. Septic Permits + Subdivision Review, quoted and re-checked
  20. 76-2-215. Accessory dwelling units -- regulations -- restrictions, MCA (Montana statewide rule), quoted and re-checked
  21. Public Use Rules and Regulations (Montana statewide rule), quoted and re-checked
  22. Yellowstone County Floodplain Permits, quoted and re-checked
  23. Approach Manual for Landowners and Developers (Montana statewide rule), quoted and re-checked
  24. Annual precipitation: Bolthole Index county data
  25. Share of years in severe drought: Bolthole Index county data
  26. Effective property tax rate: Bolthole Index county data
  27. Median property tax bill: Bolthole Index county data
  28. Typical home insurance premium: Bolthole Index county data
  29. Septic Permits + Subdivision Review, quoted and re-checked

Written October 9, 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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Compared with neighboring counties

Like 5 of its 6 neighbors, Yellowstone County requires no county building permit for a home.

RuleYellowstone CountyMusselshell CountyStillwater CountyGolden Valley CountyBig Horn CountyTreasure CountyCarbon County
Building permitNot requiredNot requiredLimitedNot requiredNot requiredNot requiredNot required
County zoningYesNoYesNot publishedNot publishedNoYes
Septic permitsRiverStone HealthCounty Sanitation ServicesCounty Env. Health Dept.County SanitarianCounty Public Health Dept.County SanitarianCounty Env. Health Dept.

County locator

Yellowstone County in Montana

55
County map
Yellowstone County highlighted among the Montana counties · colored by Index score

How Yellowstone County scores

Seclusion75100% ev.
Self-Sufficiency18100% ev.
Admin Boringness72100% ev.
Durability62100% ev.
Property Autonomy83100% ev.
Carry Cost77100% ev.

Evidence strength: 100%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$403kTypical home
0.8%Property tax
$1,216Land / acre
14.6"Annual rain
12.3% of yrsSevere drought
10.5 / yr (+9.2)Mid-century 100°F days
20.6 daysMid-century dry spell
0.99" (+6.2%)Mid-century 1-day rain
1.25×Wildfire change factor
100%Forward climate coverage
$2,302Home insurance / yr
2.2% / yrInsurance growth
0.58%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
8,697Radius comparison (15 mi)
64.9People / sq mi
4.7%Federal land
78.7%Land at 15% slope or less
19.1%Soils rated "not limited" for septic (strict USDA rating)
305,240 acWorkable land screen
4.8%Wooded land
7.4 tonsBiomass / forest ac
46.6°FAvg temp

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Cities and towns in Yellowstone County

Inside a city or town, that city usually issues building permits and sets zoning; the county’s rules above cover unincorporated land. Septic, wells and floodplain rules usually stay with the county or state everywhere.

Not yet researched: Town of Broadview

Answers from the rulebook for Yellowstone County

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

Yellowstone County rules

  • Building permitNot required

    County-issued building permits and certificates for structures outside Billings city limits.

    • This finding concerns Yellowstone County issuance; separate state electrical, plumbing, mechanical, floodplain, septic, utility, or other permits may apply.
    • Municipal requirements may differ inside incorporated jurisdictions.
    “Yellowstone County does not issue Building Permits or Certificates of Occupancy for structures outside the city limits of Billings.”
    One more reviewed finding on this topic
    • Not required — County-issued building permits for structures outside the Billings city limits.
      “Yellowstone County does not issue Building Permits or Certificates of Occupancy for structures outside the city limits of Billings. These structures are not subject to the same restrictions and permits as those located within the city limits.”
  • Owner-builder exemption · follows from the permit answerNot needed

    Unincorporated Yellowstone County: no county building permit is required, so there is no permit to be exempt from and you may build your own home. State licensing for electrical, plumbing and HVAC work may still apply.

    • This is limited to Yellowstone County issuance outside Billings city limits; it does not establish requirements within Billings or other local jurisdictions.
    • Separate state permit requirements and exemptions may still apply.
    “Yellowstone County does not issue Building Permits or Certificates of Occupancy for structures outside the city limits of Billings. These structures are not subject to the same restrictions and permits as those located within the city limits.”
  • Certificate of occupancyNot required

    County-issued certificates of occupancy for structures outside Billings city limits.

    • The county notice does not resolve state or municipal certificate requirements for other jurisdictions.
    “Yellowstone County does not issue Building Permits or Certificates of Occupancy for structures outside the city limits of Billings.”
    One more reviewed finding on this topic
    • Not required — County-issued certificates of occupancy for structures outside the Billings city limits.
      “Yellowstone County does not issue Building Permits or Certificates of Occupancy for structures outside the city limits of Billings. These structures are not subject to the same restrictions and permits as those located within the city limits.”
  • County-wide zoningPresent (with conditions)

    County zoning regulations in the county's zoning jurisdiction; exact territorial coverage and the official zoning-map boundary require review of the full zoning-code PDF.

    • The official county minutes identify a County Zoning Code and County Zoning Regulations.
    • Municipal zoning jurisdictions may apply inside incorporated municipalities.
    “This is an amendment to the County Zoning Regulations. The amendments cover 12 sections of the 2020 Yellowstone County Zoning code.”
  • Local zoningVaries (with conditions)

    Aggregate of zoning jurisdictions within Yellowstone County; the county GIS identifies separate zoning layers for Billings, Broadview, and Laurel.

    • This is an aggregate county record and does not mean Yellowstone County administers each municipal ordinance.
    • Applicable requirements depend on the municipality or other mapped zoning jurisdiction.
    “Billings Zoning (4) Broadview Zoning (0) Laurel Zoning (8)”
  • Zoning districtsPublished (with conditions)

    Official Yellowstone County GIS zoning layers and mapped municipal zoning jurisdictions.

    • The map service identifies zoning districts and separate Billings, Broadview, and Laurel zoning layers.
    • The GIS publication does not by itself establish the substantive dimensional standards of each district.
    “Layers: Laurel Planning Jurisdiction (6) Zoning Jurisdictions (7) Entryway Zoning District (1) Zoning Districts (2) Billings Zoning (4) Broadview Zoning (0) Laurel Zoning (8)”
  • Who permits septicMixed (with conditions)

    Subdivision sanitation review and onsite wastewater permitting in Yellowstone County.

    • Parcels less than 20 acres use Montana DEQ review and approval.
    • Parcels 20 acres or more use the local review process.
    • RiverStone Health administers the local septic permit and inspection steps described on the page.

    parcel threshold: < 20 acres (DEQ review applies below the threshold; local review applies at 20 acres or more)

    “Parcels less than 20 acres in size are subject to the Montana Department of Environmental Quality (DEQ) review and approval process. Parcels 20 acres or more are subject to the local review process.”
  • Septic permitRequired

    New and repaired onsite wastewater systems in Yellowstone County.

    • The property must first be approved through the DEQ or local review process.
    • A Permit Tracking Sheet must verify an assigned address, an approach permit, and that the property is not in a floodplain.
    • The applicant must submit the tracking sheet, detailed lot layout, required fee, and bedroom count for residential property.
    • A permit must be issued before the system is placed into use.
    “Both new and repaired systems must be inspected and permitted before placing the system into use. At time of installation, call RiverStone Health Environmental Health Services at 406.256.2770 to schedule an inspection. Upon completion of a satisfactory inspection, a permit will be issued.”
  • Septic inspectionRequired

    New and repaired onsite wastewater systems in Yellowstone County.

    • Inspection must occur before the system is placed into use.
    • The applicant must call RiverStone Health Environmental Health Services at installation to schedule inspection.
    • A satisfactory inspection precedes permit issuance.
    “Both new and repaired systems must be inspected and permitted before placing the system into use. At time of installation, call RiverStone Health Environmental Health Services at 406.256.2770 to schedule an inspection. Upon completion of a satisfactory inspection, a permit will be issued.”
  • Subdividing landRegulated (with conditions)

    Subdivision plat and certificate-of-survey applications in Yellowstone County, as to sanitation review.

    • RiverStone Health reviews subdivision plat and certificate-of-survey applications.
    • Parcels under 20 acres use Montana DEQ review and approval.
    • Parcels 20 acres or more use local review.
    • Review fees depend on submittal complexity and the water/sewer system required.
    • Reviews may take up to 55 days.

    parcel threshold: < 20 acres (DEQ review applies below the threshold; local review applies at 20 acres or more) · review period: <= 55 days

    “RiverStone Health reviews subdivision plat and certificate of survey applications. Parcels less than 20 acres in size are subject to the Montana Department of Environmental Quality (DEQ) review and approval process. Parcels 20 acres or more are subject to the local review process. The review fee is based on the complexity of the submittal, including the type of water and sewer system required. Reviews may take up to 55 days to process.”
  • Driveway accessRequired

    Construction of a new approach or modification of an existing approach accessing a County-managed road right-of-way.

    • The rule applies only where access is onto a right-of-way managed by Yellowstone County.
    • Construction may not begin until the County Public Works Department issues an approach permit.
    • Completion is due within one year of permit issuance; failure requires a new application and another fee.

    completion deadline: 1 year (A new application and another application fee are required if incomplete.)

    “A property owner shall obtain a permit from the Yellowstone County Public Works Department for the construction of a new approach or the modification of an existing approach that provides access onto a right-of-way managed by the County.”
    One more reviewed finding on this topic
    • Limited — Approach access associated with septic-permit applications in Yellowstone County.
      “Obtain a Permit Tracking Sheet from the Yellowstone County Courthouse, Room 305. The Permit Tracking Sheet will verify that an address has been assigned, an approach permit has been issued, and that the property is not located in a floodplain.”
  • Building in a floodplainRequired

    Building projects located in a Yellowstone County floodplain or otherwise determined to require a floodplain permit.

    • The applicant must provide a legal description to determine whether the property is in the floodplain.
    • Requirements vary with each property.
    • A non-refundable $50 processing fee applies to each permit or variance application.
    • The fee covers administration, public notice, and field inspections.

    processing fee: 50 USD (non-refundable)

    “Please check with the Floodplain Office to determine whether you need a Floodplain permit for building projects.”
    One more reviewed finding on this topic
    • Limited — Development subject to Yellowstone County floodplain regulations.
      “Please check with the Floodplain Office to determine whether you need a Floodplain permit for building projects. In order to determine whether your property is located in the floodplain or not, you will need the Legal Description of the property.”
  • Permit feesPublished (with conditions)

    Private or public access connecting to a county or dedicated road.

    • The stated fees concern access permits, not all county permit categories.
    • The County may require a contractor's excavation bond and reviews access for proper sight distance.

    residential access permit fee: 75 USD (Access connecting to a county or dedicated road.) · commercial access permit fee: 150 USD (Access connecting to a county or dedicated road.)

    “Any private or public access that connects to a county or dedicated road will need to be permitted. A permit for a residential access is $75.00 and a commercial access is $150.00.”
  • Permit processPublished (with conditions)

    New or modified driveway approaches accessing a County-managed right-of-way.

    • A permit must issue before construction in the County-managed right-of-way.
    • The owner has one year from issuance to complete construction or modification; otherwise a new application and fee are required.
    • A general site plan must show approach location, culvert diameter if applicable, distances to existing approaches and property lines, and approximate building location.

    completion deadline: 1 year (Measured from issuance; a new application and fee are required if work is not complete.)

    “A property owner shall obtain a permit from the Yellowstone County Public Works Department for the construction of a new approach or the modification of an existing approach that provides access onto a right-of-way managed by the County. A property owner shall not perform any construction on a new or existing approach in the right-of-way of a road managed by the County until the Department has issued an approach permit.”

Montana rules that apply here

  • 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.”
    3 more reviewed findings on this topic
    • Adopted (with conditions) — Residential and commercial buildings across Montana, including applicable areas of Yellowstone County.
      “In addition, the program is responsible for adopting a uniform state building code, which is enforced statewide for residential and commercial buildings across Montana.”
    • Adopted — State building-code program outside certified local-government jurisdictions and where otherwise applicable.
      “NOTE: The Bureau has adopted the 2000 editions of the international building code (IBC) and international residential code (IRC) with an effective date of September 27, 2002.”
    • Partial — Montana's statewide building-code framework for residential and commercial construction.
      “In Montana, cities, counties and towns have the option to enforce local building, electrical, plumbing, and mechanical codes, all or in part (except for state-owned agencies, which must be permitted through this Department). These local building code enforcement programs must be certified by the BC Program. The remaining cities, counties and towns that have chosen not to enforce building codes, fall under the jurisdiction of the BC Program. [...] the program is responsible for adopting a uniform state building code, which is enforced statewide for residential and commercial buildings across Montana.”
  • InspectionsLimited

    Construction subject to the state building-permit program.

    • The permit holder must call the building inspector at least 24 hours before a requested inspection.
    • The inspector has 72 hours from notification to perform the requested inspection.
    • State inspection requirements do not establish requirements for certified local jurisdictions.

    advance notice: >= 24 hours · inspection response period: <= 72 hours

    “at least 24 hours before a requested inspection”
    One more reviewed finding on this topic
    • Limited — Buildings and other projects requiring permits under Montana state building-code jurisdiction; certified local governments may perform inspections within their certified jurisdictional areas.
      “The BC Program establishes and enforces statewide codes by issuing permits and performing inspections.”
  • Living in an RVLimited

    RV, camper-trailer, and other trailer overnight use for general recreation on legally accessible Montana state trust land administered by DNRC.

    • A Conservation License is required for dispersed camping on state trust land.
    • RV or trailer camping must be within 50 feet of a customary access point; motorized vehicles must be parked within 50 feet of a customary access point, and the camper or trailer may not be set up farther away by driving beyond that point.
    • On leased or licensed land, the stay limit is 2 days.
    • On unleased or unlicensed land, the stay limit is 16 days within a 30-day period.
    • Within a designated campground, the stay limit is 16 days within a 30-day period.
    • The local DNRC field office should be contacted to confirm whether land is leased.
    • Pets must be leashed or otherwise controlled.
    • Overnight horses must be restrained, may not remain in a stream riparian zone for more than one hour, and must use certified weed-seed-free feed.
    • Campfires are generally permitted within designated campgrounds and on unleased or unlicensed land but are not allowed on leased land.
    • Cutting firewood requires a separate permit from the local DNRC field office, and fireworks are not allowed on state land.
    • State Parks, Fishing Access Sites, and Wildlife Management Areas are managed by Montana Fish, Wildlife and Parks rather than under this DNRC camping page.

    RV/trailer distance from customary access point: <= 50 ft (Motorized vehicles must be parked within 50 feet; the page states the camper or trailer may not be driven farther to set it up.) · maximum stay on leased or licensed land: 2 days · maximum stay on unleased or unlicensed land: 16 days within a 30-day period · maximum stay within designated campground: 16 days within a 30-day period

    “TRAILER/RV etc. Camp within 50 ft of a customary access point. Motorized vehicles must be parked within 50 ft of a customary access point. You may not drive further to set up a camper or trailer. On leased or licensed land: 2 days On unleased/unlicensed land: 16 days within a 30-day period Within designated campground: 16 days within a 30-day period”
  • Manufactured homesAllowed (with conditions)

    Manufactured housing used as residential housing within Montana municipalities that exercise zoning powers under MCA Title 76, chapter 2, part 3.

    • Municipal zoning regulations may not treat manufactured housing or factory-built housing units differently from other residential units.
    • Placement remains subject to applicable municipal zoning districts, permits or variances where required, building-code requirements, and other applicable health and safety rules.
    • The statute defines manufactured housing as a single-family dwelling built offsite in a factory and compliant with applicable prevailing HUD standards; a manufactured home does not include a mobile home or housetrailer as defined in 15-1-101, MCA.
    • The source addresses municipal zoning and does not establish unrestricted occupancy on unzoned or county land statewide.
    “Zoning regulations adopted under this part may not treat manufactured housing or factory-built housing units differently from any other residential units.”
  • Accessory dwellingsAllowed (with conditions)

    Accessory dwelling units in jurisdictional areas where a Montana county has established zoning regulations under MCA Title 76, chapter 2, part 2.

    • The county zoning regulations must allow at least one accessory dwelling unit by right on a lot or parcel containing a single-family dwelling.
    • The unit may be attached, detached, or internal.
    • The county may not require owner occupancy, a familial, marital, or employment relationship between occupants, or impact fees; private restrictive covenants remain possible but cannot be required as a permit, license, or use condition.
    • A county may charge up to $250 for a one-time ADU application-review fee, in addition to usual building fees.
    • Applicable building codes, fire codes, and public-health and safety regulations still apply.
    • The county may require expedited sanitation review for an ADU on a parcel with existing public water and wastewater capacity; the 15-day expedited-review provision terminates September 30, 2029.
    • The statute applies to a county that exercises zoning powers; it does not itself create county zoning where none exists.

    maximum one-time application-review fee: <= 250 USD (Usual building fees may also be required.) · expedited sanitation review: 15 days (Parcel must have existing public water and wastewater service with capacity.)

    “In jurisdictional areas where the board of county commissioners has established zoning regulations under this part, the regulations must allow a minimum of one accessory dwelling unit by right on a lot or parcel that contains a single-family dwelling.”
    One more reviewed finding on this topic
    • Allowed (with conditions) — Accessory dwelling units in Montana municipalities that exercise zoning powers under MCA Title 76, chapter 2, part 3.
      “A municipality shall adopt regulations under this chapter that allow a minimum of one accessory dwelling unit by right on a lot or parcel that contains a single-family dwelling.”
  • Well permitLimited

    New groundwater developments in Montana using 35 gallons per minute or less and no more than 10 acre-feet per year.

    • All water uses starting after June 30, 1973, require a water right either through a water-use permit or an exception to the permitting process.
    • The development may qualify for the exception; qualification is not automatic.
    • Completed groundwater uses that meet the permit exception receive a Groundwater Certificate rather than a water permit.
    • A permitted water right is required for a combined appropriation from the same source by two or more wells or developed springs exceeding 10 acre-feet, regardless of flow rate.
    • All lots in a multi-phase subdivision must share a combined water-use limit of 10 acre-feet per year to qualify for a permit exception.
    • Beginning January 1, 2026, a water user intending to develop water use through a permit exception must file a Notice of Intent with DNRC before using water from an exempt well.
    • DNRC reviews a correct and complete Notice of Intent within 10 business days; if eligible, it authorizes the Notice of Intent and gives the user five years to complete the project, put the water to use, and file a Notice of Completion.
    • If the proposed use is not eligible, the Notice of Intent is denied and the user is directed to the water-right permit process.
    • The Notice of Intent filing fee is $400.
    • An authorized Notice of Intent expires after five years, with an opportunity for one five-year extension.

    maximum flow rate: <= 35 gpm · maximum annual volume: <= 10 acre-feet per year · Notice of Intent fee: 400 USD (Beginning January 1, 2026) · Notice of Intent review period: 10 business days (For a correct and complete Notice of Intent) · authorized Notice of Intent term: 5 years (One five-year extension opportunity is available)

    “Permit Exceptions, a.k.a. Exempt Wells: Small groundwater developments that use 35 gpm or less and do not exceed 10 acre-feet per year are known as “exempt wells” and may qualify for an exception to the water permit process.”
    One more reviewed finding on this topic
    • Required — Surface-water uses and groundwater uses exceeding 35 gallons per minute or 10 acre-feet per year in Montana.
      “Water Permits: A water permit is required for all surface water use and groundwater uses over 35 gallons per minute (gpm) or 10 acre-feet per year.”
  • Agricultural exemptionAvailable

    Farm and ranch buildings outside cities certified to issue their own building permits, under the state building-permit program.

    • This is an exemption from the state building permit only.
    • Local zoning, floodplain, sanitation, subdivision, electrical, plumbing, and mechanical requirements may still apply.
    “for areas outside cities certified to issue their own permits, state law exempts: (a) farm and ranch buildings; (b) mining buildings on mining property; (c) petroleum refineries and pulp and paper mills (except office and shop buildings); (d) residential buildings containing less than five dwelling units (except when serving transient guests); and (e) private garages and private storage buildings used for the owner's own use (not part of a commercial enterprise or business) from the need to obtain a state building permit.”
  • 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”
  • 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;”
    One more reviewed finding on this topic
    • Limited — Dispersed and designated-campground temporary camping on legally accessible Montana state trust land administered by DNRC.
      “Dispersed camping is allowed on state trust land with the appropriate permit and with certain restrictions. Dispersed camping on state trust land is allowed with a Conservation License. Camping that is incidental to hunting or fishing is permitted through your conservation license, and no additional permitting is required. Group camping requires a special recreational use license. On leased or licensed land: 2 days On unleased/unlicensed land: 16 days within a 30-day period Within designated campground: 16 days within a 30-day period”
  • county zoning authorityGeneral

    Montana county boards of commissioners' authority to adopt zoning regulations, including in unincorporated portions of established jurisdictional areas.

    • The board of county commissioners must have adopted a growth policy pursuant to Title 76, chapter 1.
    • Zoning may be adopted for all or parts of the jurisdictional area in accordance with Title 76, chapter 2, part 2.
    • Within unincorporated portions of an established jurisdictional area, the board may establish zoning regulations by resolution or divide the county into zoning districts.
    • Zoning regulations may regulate the erection, construction, reconstruction, alteration, repair, location, or use of buildings or structures and the use of land.
    • An action challenging creation of a zoning district or adoption of zoning regulations must be commenced within 6 months after the board's order.
    • Regulations in one district may differ from those in other districts.
    • The statute also states that zoning regulations may not treat manufactured housing or factory-built housing units differently from other residential units, subject to the statutory presumption concerning placement.

    challenge period: 6 months (after the date of the board order creating the district or adopting the regulations)

    “For the purpose of promoting the public health, safety, morals, and general welfare, a board of county commissioners that has adopted a growth policy pursuant to chapter 1 is authorized to adopt zoning regulations for all or parts of the jurisdictional area in accordance with the provisions of this part.”
    One more reviewed finding on this topic
    • General — Montana county boards of commissioners adopting zoning regulations for all or parts of their jurisdictional areas, including unincorporated portions where the statutory prerequisites are met.
      “a board of county commissioners that has adopted a growth policy pursuant to chapter 1 is authorized to adopt zoning regulations”
  • county building authorityGeneral

    Montana counties may adopt and enforce building codes and require construction permits for residential construction in unincorporated county areas, subject to the statutory certification, geographic, code-content, and permit requirements.

    • A county may adopt a building code by ordinance or resolution, or authorize adoption by administrative action.
    • A county may adopt its building code on a countywide basis unless a city or town within the county has adopted a building code; the county may not enforce its county building code within that city or town.
    • The county code-enforcement program must be certified by the Montana Department of Labor and Industry.
    • The current adopted code, current fee list, and current enforcement plan must be filed with and approved by the Department.
    • Inspectors must satisfy the stated state-licensing or approved national-certification requirements.
    • Except for voluntary incentive-based energy-conservation standards, the county may not adopt or enforce a building code more stringent than the code adopted by the Department or required by state law.
    • The county may prohibit construction from commencing until the required permit is issued after compliance is shown.
    • The general construction-permit requirement applies to buildings subject to Title 50, chapter 60, parts 1 through 4.
    • State agency-owned buildings remain under state Department jurisdiction for plan review, permitting, and inspections.
    “The local legislative body of a county, city, or town may adopt a building code to apply to the county, city, or town by an ordinance or resolution, as appropriate: (a) adopting a building code; or (b) authorizing the adoption of a building code by administrative action.”
    One more reviewed finding on this topic
    • General — Montana counties' authority to adopt and enforce building codes and require building-code administration for construction in county areas, including unincorporated areas.
      “The local legislative body of a county, city, or town may adopt a building code to apply to the county, city, or town by an ordinance or resolution, as appropriate: (a) adopting a building code; or (b) authorizing the adoption of a building code by administrative action.”

Still unanswered

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

  • Minimum dwelling size — Minimum dwelling size in Yellowstone County.
  • Minimum lot size — Minimum lot size in Yellowstone County.
  • Setbacks — Residential setbacks in Yellowstone County.
  • Lot coverage — Lot coverage limits in Yellowstone County.
  • Building height — Building-height limits in Yellowstone County.
4 more unanswered
  • Camping on your land
  • Tiny homes
  • Off-grid sanitation
  • Mandatory utility hookup

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.

Water rights & wells in Yellowstone County

Whether a new home can legally get its own water here — the sub-state groundwater regime, from Montana’s water agency.

Actively managed

This basin is under active state management — new water use is scrutinized, though a domestic well is usually still allowed.

Household wellExempt up to a limit

Montana's exempt-well exception (85-2-306 MCA) was tightened after Upper Missouri Waterkeeper v. DNRC (2024), and from Jan 1, 2026 appropriators must file a Notice of Intent with DNRC before putting exempt groundwater to use.

Limit: 35 gpm or less AND ≤10 acre-ft/yr; a combined appropriation exceeding 10 acre-ft needs a permit regardless of flow rate

Montana DNRC — Water Rights Permit Exceptions (Exempt Wells) ↗

Prior-appropriation state (first in time, first in right). Groundwater rules change and basin boundaries follow the aquifer, not the county line — confirm current well and appropriation rules with the Montana state water agency before you buy or drill.Groundwater governance as of Jul 2026, cited to each administering agency.

Living off-grid in Yellowstone County, Montana

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

Yellowstone County scores 55/100 on the Bolthole Index, a solid county profile. Its strengths: a stronger property-autonomy legal backdrop and manageable long-term carry cost. Watch-outs: weak self-sufficiency basics: only 14.6″ of rain a year.

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

Yellowstone County does not require a county building permit for a home in unincorporated areas, and it enforces county zoning. Onsite septic is permitted by RiverStone Health, Environmental Health Services (Yellowstone County local health department). Owner-builders may act as their own contractor to build their home. 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.

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

Living in an RV on your own land in Yellowstone County is limited to specific cases: Statewide rule. RV, camper-trailer, and other trailer overnight use for general recreation on legally accessible Montana state trust land administered by DNRC. A Conservation License is required for dispersed camping on state trust land. RV or trailer camping must be within 50 feet of a customary access point; motorized vehicles must be parked within 50 feet of a customary access point, and the camper or trailer may not be set up farther away by driving beyond that point. Confirm with the county before relying on it.

How much does land cost in Yellowstone County, Montana?

Land in Yellowstone County runs about $1,216 per acre, based on the latest county data.

What is the water situation in Yellowstone County?

Yellowstone County gets about 14.6" of rain a year, with severe drought in roughly 12.3% of years. On water rights, Yellowstone County lies in the Lockwood Solvent Groundwater Plume Controlled Groundwater Area — ~331 acres east of Billings; contamination-driven CGWA where new wells require a permit..

How remote is Yellowstone County?

A typical private-land location has about 8,697 people within 15 miles and 274,951 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Yellowstone compares in Montana

Compare side-by-side →See all 56 Montana counties ranked →