Bolthole Index

Stillwater County, Montana

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

65Index Score / 100
#25 of 56 in Montana

Unincorporated Stillwater County, Montana has no certified local building-code program; Montana issues building permits for nonexempt projects, while private homes that do not serve transient guests are exempt12. County conditional-use permits cover new multifamily, work-camp, planned-unit, commercial and industrial development3. County zoning excludes Columbus’s extra-territorial jurisdiction; Columbus sets its own zoning and prohibits septic systems inside town limits456. Elsewhere, septic construction authorization goes through County Environmental Health after DEQ or county sanitation approval78.

At a glance

County conditional-use permit
Required for new multifamily, work-camp, planned-unit, commercial and industrial development3
Building-code program
No certified county program; Montana permits and inspects nonexempt projects129
Land-use rules
County development regulations apply outside excluded Columbus, state and federal jurisdictions4
Residential setbacks
No general residential setback; conditional-use projects have height-based, front, side and rear setbacks1011
Septic permit
County construction authorization follows DEQ or county sanitation approval; septic systems prohibited inside Columbus786
RV or tiny-home living
Not confirmed countywide; flood-hazard areas allow a narrow temporary-use exception12
Agricultural use
Qualifying agricultural uses are exempt from the county development permit13
Floodplain development
A separate permit is required in regulated flood-hazard areas14

Who to call

Zoning

Stillwater County Planning Office

Land-use planning, zoning, subdivision review and county development-permit questions

406-322-8050

431 Quarry Road, Columbus, MT 59019

Floodplain permits

Stillwater County Floodplain Administrator

Floodplain determinations and development permits in regulated flood-hazard areas

406-322-8064

cindyg@stillwatercountymt.gov

431 Quarry Road, Columbus, MT 59019

Septic permits

Stillwater County Environmental Health Department

Onsite wastewater permits and inspections

406-322-8055

431 Quarry Road, Columbus, MT 59019

Roads & driveways

Stillwater County Road & Bridge Department

County-road maintenance and encroachment-permit applications

406-322-5335

865 Highway 10 West, Columbus, MT 59019

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

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

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

Stillwater County does not operate a certified local building-code program, so Montana handles building permits and inspections for projects under state building-code jurisdiction19. Montana requires state building permits for nonexempt buildings; exemptions include farm and ranch buildings, private homes and apartments with four or fewer units that do not serve transient guests, and private storage buildings and garages2. Separately, Stillwater County requires a conditional-use permit before new multifamily, work-camp, commercial, industrial or planned-unit construction begins3. Qualifying agricultural uses do not require that county development permit, but septic permits, floodplain development permits, access requirements and applicable state building permits remain separate151617. Ask Planning to classify the use; for a state building permit, submit plans and the application to the Montana Building Codes Program1819.

Who issues building permits in Stillwater County, and how do you reach them?

Direct state building-permit and inspection questions to the Montana Building Codes Program because Stillwater County has no certified local building-code program19. Start county land-use and conditional-use-permit questions with the Stillwater County Planning Office at 431 Quarry Road, Columbus, MT 59019, or 406-322-805020. Planning routes submitted forms to Environmental Health, the Floodplain Administrator, GIS/Rural Addressing, and Road & Bridge when needed21. Stillwater County Environmental Health handles county septic construction authorization and inspections, but septic systems are prohibited inside Columbus town limits8226. Floodplain development permits go through the Floodplain Administrator, and county-road encroachment-permit applications go to Road & Bridge2324.

Does Stillwater County have zoning?

Stillwater County's development and zoning regulations govern unincorporated land outside the City of Columbus extra-territorial zoning jurisdiction and state and federal land25. Columbus sets its own zoning, including an extra-territorial area shown on its zoning map; County Planning administers county and Columbus subdivision regulations526. Septic systems are prohibited inside Columbus town limits6. Stillwater County sets no general setback for residential property, but development requiring a conditional-use permit must be set back at least half the structure’s height, with minimums of 10 feet at the front and 5 feet at the sides and rear1011. For a newly subdivided parcel with individual water and sewer, at least one acre of buildable land must lie outside the delineated floodway, and every lot needs at least 30 feet of frontage on its access street or road27. Those are subdivision standards, not a general minimum lot size for every existing parcel27. Countywide rules for RV living, tiny homes, minimum dwelling size and lot coverage could not be confirmed; ask Planning about the exact parcel and use.

How do septic permits work in Stillwater County?

Stillwater County septic construction requires DEQ or county sanitation approval first: properties under 20 acres require a DEQ Certificate of Subdivision Approval, and properties over 20 acres require county sanitary approval7. Ask Environmental Health which approval applies to a parcel of exactly 20 acres7. Obtain county construction authorization before installation; the published septic-system permit fee is $200828. The contractor must request inspection before 3 p.m. the preceding day, and the sanitarian issues the septic permit after a compliant inspection22. Inspection or licensed-installer verification is required before covering the system; confirm the accepted procedure with Environmental Health2930. Only 7.6% of county soils lack severe limitations for conventional drain fields, so obtain a site evaluation early31. Off-grid wastewater systems, including gray-water disposal, require authorized-consultant design and county approval; holding tanks, outhouses and porta-potties are prohibited3233. Septic systems are prohibited inside Columbus town limits6.

Can you live in an RV or tiny home in Stillwater County?

Stillwater County's general rules for residential or long-term RV occupancy and tiny-home occupancy could not be confirmed; ask Planning about the exact parcel, structure and duration. Within a regulated flood-hazard area, an RV may stay without a floodplain permit for fewer than 180 consecutive days only if it remains licensed and highway-ready, uses quick-disconnect utilities, has no permanent additions, and requires no structures, fill, grading or excavation12. That floodplain exception does not establish that residential RV use is allowed by zoning or other law12. A tiny home or RV still needs an approved wastewater solution: consultant-designed gray-water disposal needs county approval, while holding tanks, outhouses and porta-potties are prohibited3234. Countywide rules for minimum dwelling size, temporary camping, manufactured homes also could not be confirmed; put the exact proposal in writing to Planning.

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

  1. Ask Planning which jurisdiction controls the parcel and whether the proposed use needs a county conditional-use permit353.
  1. Ask the Floodplain Administrator whether the site is regulated; grading, fill, excavation and construction in a regulated flood-hazard area require a floodplain development permit14.
  1. Obtain DEQ or county sanitation approval, then county septic construction authorization through Environmental Health; schedule inspection before backfilling7830.
  1. Before using a qualifying exempt well, file the required Notice of Intent; uses over 35 gallons per minute or 10 acre-feet per year require a water permit36.
  1. Ask the Montana Building Codes Program which state building, plumbing and other trade permits and inspections apply29. A homeowner personally doing plumbing in a personal residence may be exempt from the plumbing permit if the home is neither speculative construction nor a rental37.
  1. Confirm legal and physical access; county conditional-use review requires legal and physical access and may require road-maintenance agreements or bonding, while a state-highway approach needs MDT approval3839.

What should you check before buying land in Stillwater County?

Make septic suitability, legal access, flood status and water rights purchase contingencies. Only 7.6% of Stillwater County soils are rated without severe limitations for conventional drain fields, so obtain a site evaluation before treating a homesite as buildable31. A qualifying exempt well requires a Notice of Intent before use, and groundwater use over 35 gallons per minute or 10 acre-feet per year requires a water permit36. Ask the Floodplain Administrator about the exact building area because grading, excavation, fill and construction in regulated flood-hazard areas require a floodplain development permit40. Confirm whether access meets a county road or state highway because county encroachment permits and state-highway approach permits have different authorities2439. Ask Planning about land-division review, including certificate-of-survey and exempt divisions; the published survey-review fee is $2004142. New lots with individual water and sewer also have buildable-area and road-frontage standards27.

Watch-outs

  • County and state approvals are separate: county conditional-use review covers specified development types, while Montana permits nonexempt buildings32.
  • Stillwater County requires authorized-consultant design and county approval for off-grid wastewater systems, including gray water; holding tanks, outhouses and porta-potties are prohibited3233.
  • Floodplain grading, excavation, fill and construction require a county floodplain development permit17.
  • The homeowner plumbing-permit exemption is narrow: the owner must do the work personally in a personal residence that is neither speculative construction nor a rental37.

Sources

  1. Stillwater County, MT Planning (2026 county census)
  2. Building Permit FAQ | Montana Department of Labor and Industry, quoted and re-checked
  3. Stillwater County Development and Zoning Regulations, quoted and re-checked
  4. Stillwater County Development and Zoning Regulations, quoted and re-checked
  5. Town of Columbus: Columbus Code § 17.12.030—Boundaries of districts and zoning map (Stillwater County), quoted and re-checked
  6. Town of Columbus: Columbus Code § 13.08.100—Septic systems not allowed (Stillwater County), quoted and re-checked
  7. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  8. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  9. Building Permits | Montana Building Codes Program, quoted and re-checked
  10. Planning | Stillwater County, MT, quoted and re-checked
  11. Stillwater County Development Regulations, quoted and re-checked
  12. Stillwater County Floodplain Hazard Management Regulations, quoted and re-checked
  13. Stillwater County Development and Zoning Regulations, quoted and re-checked
  14. stillwatercountymt.gov, quoted and re-checked
  15. Stillwater County Development Regulations, quoted and re-checked
  16. Stillwater County Wastewater Disposal Regulations, quoted and re-checked
  17. Planning | Stillwater County, MT, quoted and re-checked
  18. Stillwater County Development and Zoning Regulations, quoted and re-checked
  19. Building Permits (Montana statewide rule), quoted and re-checked
  20. Stillwater County Planning Office (stillwatercountymt.gov)
  21. Frequently Asked Questions - Stillwater County, quoted and re-checked
  22. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  23. Stillwater County Floodplain Administrator (stillwatercountymt.gov)
  24. Stillwater County Road & Bridge Department (stillwatercountymt.gov)
  25. Stillwater County Development Regulations, quoted and re-checked
  26. Planning | Stillwater County, MT, quoted and re-checked
  27. Stillwater County, Montana, Subdivision Regulations 2022 — Lot Standards, quoted and re-checked
  28. Planning, quoted and re-checked
  29. Stillwater County Wastewater Disposal Regulations, quoted and re-checked
  30. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  31. 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
  32. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  33. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  34. How to Obtain a Septic Permit in Stillwater County, quoted and re-checked
  35. Planning, quoted and re-checked
  36. Exempt Well Updates | Montana DNRC, quoted and re-checked
  37. Plumbing Permits, quoted and re-checked
  38. Stillwater County Development Regulations, quoted and re-checked
  39. Approach Manual for Landowners and Developers (Montana statewide rule), quoted and re-checked
  40. Developing in the Floodplain?, quoted and re-checked
  41. stillwatercountymt.gov, quoted and re-checked
  42. Planning | Stillwater County, MT, quoted and re-checked

Written October 11, 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

Unlike 5 of its 6 neighbors, Stillwater County requires a building permit only in limited cases.

RuleStillwater CountyCarbon CountySweet Grass CountyYellowstone CountyGolden Valley CountyWheatland CountyPark County
Building permitLimitedNot requiredLimitedNot requiredNot requiredNot requiredNot required
County zoningYesYesYesYesNot publishedNot publishedYes
Septic permitsCounty Env. Health Dept.County Env. Health Dept.County Env. HealthRiverStone HealthCounty SanitarianCounty Env. HealthCounty Env. Health Dept.

County locator

Stillwater County in Montana

65
County map
Stillwater County highlighted among the Montana counties · colored by Index score

How Stillwater County scores

Seclusion78100% ev.
Self-Sufficiency38100% ev.
Admin Boringness5590% ev.
Durability44100% ev.
Property Autonomy83100% ev.
Carry Cost76100% 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 →

$505kTypical home
0.6%Property tax
$1,747Land / acre
18.4"Annual rain
11.6% of yrsSevere drought
4.9 / yr (+4.4)Mid-century 100°F days
19.3 daysMid-century dry spell
1.22" (+5%)Mid-century 1-day rain
1.26×Wildfire change factor
100%Forward climate coverage
$2,192Home insurance / yr
1.9% / yrInsurance growth
0.32%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
200,085People within 2 hr
4,402Radius comparison (15 mi)
5.1People / sq mi
18.2%Federal land
68.2%Land at 15% slope or less
7.6%Soils rated "not limited" for septic (strict USDA rating)
70,101 acWorkable land screen
18.2%Wooded land
14.5 tonsBiomass / forest ac
43.8°FAvg temp

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Cities and towns in Stillwater 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.

Answers from the rulebook for Stillwater County

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

Stillwater County rules

  • Building permitLimited

    County development permitting for new multi-family, work camps, commercial, industrial, and planned unit development in unincorporated Stillwater County.

    • A conditional use permit is required for all new multi-family, work camps, commercial, industrial development, or planned unit developments.
    • Construction shall not begin before the conditional use permit is issued.
    • State building permits may separately apply to non-exempt projects.
    “A conditional use permit must be issued under these Regulations for all new multi-family, work camps, commercial, industrial development, or planned unit developments as defined herein. Construction shall not begin prior to issuance of the conditional use permit.”
  • County-wide zoningPresent (with conditions)

    Land-use changes and development in unincorporated Stillwater County.

    • The regulations except the City of Columbus extra-territorial zoning jurisdiction and State and Federal lands.
    • Where future County regulations or state or federal law impose additional standards, the most restrictive standard applies.
    • Private agreements are not nullified; where they are less restrictive than the regulations, the regulations apply.
    “The area included within the jurisdiction of these Regulations and governed by them shall be the unincorporated areas of Stillwater County, Montana, excepting the City of Columbus extra-territorial zoning jurisdiction, as well as State and Federal lands.”
    One more reviewed finding on this topic
    • Present (with conditions) — County Development and Zoning Regulations in unincorporated Stillwater County.
      “The area included within the jurisdiction of these Regulations and governed by them shall be the unincorporated areas of Stillwater County, Montana, excepting the City of Columbus extra-territorial zoning jurisdiction, and State and Federal lands.”
  • Local zoningVaries (with conditions)

    Aggregate local zoning across unincorporated Stillwater County and incorporated/local jurisdictions.

    • The county administers county regulations in unincorporated areas, while the City of Columbus and other local jurisdictions may administer separate zoning rules.
    • The County Planning Office states that it administers Stillwater County and Town of Columbus subdivision regulations and advises the Columbus Town Council on planning and zoning issues.
    “Columbus Town Council on planning and zoning issues”
  • Zoning districtsPartial

    Published zoning and development district materials administered or linked by Stillwater County, including Columbus materials.

    • The county Planning page links both the Zoning and Development Regulation and the Columbus Zoning Districts Web Map; the materials distinguish county and Columbus jurisdictional controls.
    “Zoning and Development Regulation Columbus Zoning Districts Web Map”
  • Minimum lot sizeSpecified

    Lots created through subdivision review under the Stillwater County Subdivision Regulations, subject to applicable City of Columbus or other local zoning rules.

    • The one-acre requirement applies to each subdivided parcel with an individual water and sewer system and requires the acre of buildable land to be outside the floodplain portion of a delineated 100-year floodway.
    • The floodway is determined using official City of Columbus and/or Stillwater County Flood Hazard Maps contained in the Stillwater County Floodplain Regulations and approval by the County Floodplain Administrator.
    • All lots must have at least 30 feet of frontage on the street or road providing access.
    • Each lot must also contain a satisfactory building site and conform to current DEQ regulations, adopted zoning regulations, and the Subdivision Regulations.
    • The county Development Regulations apply to unincorporated areas, except the City of Columbus extra-territorial zoning jurisdiction, and state and federal lands.

    minimum buildable land outside delineated 100-year floodway for subdivided parcel with individual water and sewer system: >= 1 acre · minimum lot frontage: >= 30 feet

    “Each subdivided parcel with individual water and sewer system shall contain at least one acre of buildable land”
  • SetbacksSpecified

    New multi-family, planned unit, commercial, and industrial development requiring a County conditional use permit.

    • A conditional use permit must issue before construction begins for the listed development types.
    • No building or structure may be built within rights-of-way or easements.
    • The County development regulations exclude the City of Columbus extra-territorial zoning jurisdiction and State and Federal lands.

    structure-height setback: one half the height of the proposed structure · front property line or right-of-way setback: >= 10 feet · side and rear property line setback: >= 5 feet

    “Setbacks: all development shall be set back a minimum of one half the height of the proposed structure, and at least 10 (ten) feet from the front property line or right-of-way and 5 (five) feet from all side and rear property lines. No building or structure shall be built within rights-of-way or easements.”
    2 more reviewed findings on this topic
    • Specified — Conditional-use development in unincorporated Stillwater County.
      “There is a minimum 10-foot setback for a Conditional Use Permit (PDF) for all new multi-family, planned unit developments, commercial or industrial development.”
    • None — Residential properties in Stillwater County.
      “There are no setback regulations in Stillwater County for residential properties however, it is always in the property owner’s best interest to provide a setback, even if only minimal, from the property line to any structure.”
  • Living in an RVTemporary only

    Recreational vehicle use within Stillwater County's Regulated Flood Hazard Area.

    • The vehicle must be on the site for fewer than 180 consecutive days.
    • The vehicle must be fully licensed and ready for highway use.
    • A recreational vehicle is ready for highway use if it is on its wheels or jacking system with wheels intact.
    • The vehicle may be attached to the site only by quick disconnect type utilities and security devices.
    • The vehicle may have no permanently attached additions.
    • The use is allowed without a floodplain permit only if it is not prohibited by any other regulation or statute, does not require structures, does not require a No-Rise if in the floodway, and does not require fill, grading, excavation, or storage of materials or equipment.
    • The regulations apply only to flood hazard areas specifically adopted as Regulated Flood Hazard Areas.
    • Alteration or substantial improvement of an existing artificial obstruction or nonconforming use requires a Floodplain Permit.

    maximum site duration: < 180 consecutive days

    “The following open space uses shall be allowed without a permit in the Regulated Flood Hazard Area, provided that such uses are not prohibited by any other regulation or statute, do not require structures, do not require a No-Rise if in the floodway, and do not require fill, grading, excavation or storage of materials or equipment: [...] 4. Recreational vehicle use provided that the vehicle is on the site for fewer than 180 consecutive days and the vehicle is fully licensed and ready for highway use. A recreational vehicle is ready for highway use if it is on its wheels or jacking system with wheels intact, is attached to the site only by quick disconnect type utilities and security devices, and has no permanently attached additions; (44 CFR 60.3(c)(14))”
  • Who permits septicMixed (with conditions)

    On-site wastewater approvals and septic permitting in Stillwater County.

    • An approval statement may be issued by either Montana DEQ or Stillwater County.
    • Properties less than 20 acres require a Certificate of Subdivision Approval from MTDEQ.
    • Properties greater than 20 acres require sanitary approval issued by Stillwater County.

    acreage threshold: < 20 acres (Certificate of Subdivision Approval from MTDEQ required) · acreage threshold: > 20 acres (Stillwater County sanitary approval required)

    “In order to get a construction authorization and subsequent permit for a septic system in Stillwater County you must first have an approval statement issued by either the Montana Department of Environmental Quality (MTDEQ) or by Stillwater County.”
    2 more reviewed findings on this topic
  • Septic permitRequired

    Construction and operation of septic systems in Stillwater County.

    • Required approval statements and all other county and state permits must be obtained first.
    • Construction must not begin without a valid construction authorization form.
    • Applications are processed in order received; processing is stated as 7-14 days, with up to 30 days before authorization to begin construction.

    processing time: 7-14 days (Up to 30 days before construction authorization)

    “In order to get a septic permit in Stillwater County, there are a few things you must have first.”
    2 more reviewed findings on this topic
    • Required — On-site wastewater systems in Stillwater County.
      “When a property has an appropriate approval statement as well as all other required county and state permits, a Stillwater County Septic Application can be submitted.”
    • Required — Installation, alteration, repair, extension, or connection to wastewater treatment or disposal systems in Stillwater County.
      “unless the Department has issued an Installation Permit.”
  • Septic inspectionRequired

    County-approved septic systems in Stillwater County.

    • The contractor must call before 3 p.m. the day before readiness for inspection.
    • The sanitarian issues the county septic permit after a compliant inspection.
    “inspected for compliance before backfilling”
    2 more reviewed findings on this topic
    • Required — Septic systems constructed in Stillwater County.
      “The contractor can then begin construction and must call before 3pm the day prior to being ready for an inspection to request an inspection and get it scheduled on the sanitarian calendar. Upon completion of a compliant septic system inspection, the sanitarian will issue a Stillwater County septic permit.”
    • Required — County-approved wastewater treatment systems in Stillwater County.
      “required prior to covering the completed wastewater treatment system.”
  • Off-grid sanitationProhibited

    Holding tanks, outhouses, porta-potties, and unapproved gray-water systems in Stillwater County.

    • The prohibition is stated in the County septic-permitting process and applies under current regulations.
    • Only systems designed by an authorized consultant and approved by Stillwater County are allowed.
    “Holding tanks, outhouses, porta-potties, etc. are not allowed”
    3 more reviewed findings on this topic
    • Prohibited — Holding tanks, outhouses, porta-potties, and unapproved gray-water disposal systems in Stillwater County.
      “Holding tanks, outhouses, porta-potties, etc. are not allowed”
    • Limited — Off-grid wastewater and gray-water disposal in Stillwater County.
      “Please know that only systems (including gray water disposal) that are designed by an authorized consultant and approved by Stillwater County are allowed. Holding tanks, outhouses, porta-potties, etc. are not allowed under current regulations.”
    • Prohibited — Holding tanks, outhouses, porta-potties, and similar off-grid sanitation methods in Stillwater County.
      “Holding tanks, outhouses, porta-potties, etc. are not allowed under current regulations.”
  • Agricultural exemptionAvailable

    Agricultural uses in unincorporated Stillwater County.

    • The regulations define agricultural uses as production of crops or livestock and associated facilities and activities.
    • Commercial agriculture and commercial feed operations are excluded from the definition.
    • Other laws and permits may still apply.
    “Agricultural uses are allowed without the requirement of obtaining a development permit.”
    One more reviewed finding on this topic
    • Available — Agricultural uses under the Stillwater County Development Regulations.
      “Agricultural Uses – Agricultural uses are allowed without the requirement of obtaining a development permit.”
  • Subdividing landRegulated (with conditions)

    Subdivision and exempt-subdivision review in Stillwater County.

    • The County Planning Office administers the Stillwater County 2022 Subdivision Regulations.
    • Certificate-of-survey and other exempt subdivisions generally receive staff review.
    • The county FAQ states a $200 review fee for surveys submitted.

    survey review fee: 200 USD (for surveys submitted as described in the county FAQ)

    “Please refer to the Stillwater County 2022 Subdivision Regulations (PDF).”
    2 more reviewed findings on this topic
    • Regulated (with conditions) — Subdivision and land division in Stillwater County, with separate City of Columbus rules where applicable.
      “The Montana Subdivision and Platting Act requires all local governments to adopt subdivision regulations that are consistent with the State’s regulations.”
    • Regulated (with conditions) — Subdivision and exempt-subdivision review administered by the Stillwater County Planning Office and, where applicable, the Town of Columbus.
      “Stillwater County and Town of Columbus Subdivision Regulations”
  • Driveway accessRequired

    Development requiring county conditional-use review in Stillwater County.

    • Legal and physical access must be provided.
    • The County may require road-maintenance agreements and bonding requirements.
    “legal and physical access shall be provided to the tract of land where the development is proposed.”
    One more reviewed finding on this topic
    • Required — Conditional-use development in unincorporated Stillwater County.
      “Access: legal and physical access shall be provided to the tract of land where the development is proposed. Measures may be taken to ensure County roads are kept to an acceptable level of service, including, but not limited to, road maintenance agreements and bonding requirements.”
  • Building in a floodplainRequired

    Development within identified regulated flood-hazard areas in Stillwater County.

    • Grading, excavation, fill placement, bank stabilization, construction, and alterations within regulated flood-hazard areas require a floodplain development permit.
    • Structures damaged or improved more than 50% of market value must comply with regulations and be elevated 2 feet above designated floodplain elevation.

    substantial improvement/damage threshold: > 50 percent of market value (Structure must be built according to regulations and elevated 2 feet above designated floodplain elevation.) · elevation requirement: 2 feet (Above designated floodplain elevation.)

    “Activities such as grading, excavation, placement of fill, bank stabilization work, construction or alterations to a property within the Regulated Flood Hazard Areas require a Floodplain Development Permit.”
    2 more reviewed findings on this topic
    • Required — Grading, excavation, fill, bank stabilization, construction, or alterations within regulated flood-hazard areas.
      “Activities such as grading, excavation, placement of fill, bank stabilization work, construction or alterations to a property within the Regulated Flood Hazard Areas require a Floodplain Development Permit.”
    • Required — Development or activity within a Regulated Flood Hazard Area in Stillwater County.
      “require a Floodplain Development Permit.”
  • Permit feesPublished

    County development and septic permitting fees.

    • The Planning page links a Development Regulations Fee Schedule.
    • The septic process separately links a fee schedule; the reviewed septic fee schedule states a $200 septic system permit fee.

    septic system permit fee: 200 USD

    “STILLWATER COUNTY: SEPTIC SYSTEM PERMIT FEE $200”
  • Permit processPartial

    County development-permit process in Stillwater County.

    • New multi-family, planned unit development, commercial, and industrial development requires a conditional-use permit.
    • The Planning Office routes submissions to the County Sanitarian, Floodplain Administrator, GIS/Rural Addressing, and Road and Bridge Department as needed.
    • The County FAQ directs other building questions to the State Building Code Bureau.
    “route the submitted form(s) to the internal permitting departments”
    One more reviewed finding on this topic
    • Published — Stillwater County coordinated development and conditional-use permit processes.
      “A Conditional Use Permit (PDF) is required for all new multi-family, planned unit developments, and commercial or industrial development. The Planning Office will then route the submitted form(s) to the internal permitting departments for comment and instructions to follow up if necessary with the County Sanitarian, Floodplain Administrator in Environmental Health, GIS/ Rural Addressing, and Road and Bridge Department.”

Montana rules that apply here

  • Owner-builder exemptionConditional

    A homeowner performing plumbing installation personally in a residence within Montana state plumbing jurisdiction, including applicable areas of Stillwater County.

    • The homeowner must perform the plumbing installation personally.
    • The residence must be for the owner's personal use.
    • The residence must not be built on speculation of resale.
    • The residence must not be intended as a rental property.
    • Certified local governments may enforce the plumbing code within their jurisdictional area; other areas fall under state jurisdiction.
    “Homeowners do not need to obtain a plumbing permit provided he/she is doing the plumbing installation themselves and the residence is for the owner's personal use and not built on speculation of resale or intended as a rental property.”
    One more reviewed finding on this topic
    • Available — An owner working on the owner's property, or an owner contracting for work performed by a registered construction contractor, under Montana's construction-contractor licensing chapter.
      “(13) to an owner working on the owner's property, whether occupied by the owner or not, but this exemption does not apply to an owner”
  • 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.”
    2 more reviewed findings on this topic
    • Adopted (with conditions) — Residential and commercial buildings across Montana, including Stillwater County where state jurisdiction applies.
      “In addition, the program is responsible for adopting a uniform state building code, which is enforced statewide for residential and commercial buildings across Montana.”
    • 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

    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.”
    One more reviewed finding on this topic
    • Required — State building-code projects requiring a state building permit.
      “It is the responsibility of the permit hold to notify the inspector when work is ready for inspection and to provide access for required 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.”
  • 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.”
    2 more reviewed findings on this topic
    • Limited — Groundwater use through Montana exempt-well permit exceptions.
      “Small groundwater developments that use 35 gpm or less and do not exceed 10 acre-feet per year are known as “exempt wells””
    • 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.”
  • 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 Stillwater County.
  • Lot coverage — Lot coverage in Stillwater County.
  • Building height — General building-height limits in Stillwater County.
  • Camping on your land — Temporary camping outside an approved campground or work camp in Stillwater County.
  • Tiny homes — Tiny-home occupancy in Stillwater County.
1 more unanswered
  • 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 Stillwater 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) ↗
  • Horse Creek Controlled Groundwater Arealocalized of county

    Inside the CGWA a completed well may serve domestic/stock use at a maximum 35 gpm not to exceed 1 acre-ft/yr (versus the statewide 10 acre-ft exemption); larger uses need a permit.

    Montana DNRC — Water Rights Permit Exceptions ↗

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 Stillwater County, Montana

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

Stillwater County scores 65/100 on the Bolthole Index, a strong county profile. Its strengths: a stronger property-autonomy legal backdrop and deep seclusion — about 4,402 people within 15 miles. Watch-outs: thin water margin (18.4″/yr rainfall).

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

Stillwater County requires a building permit only in limited cases (such as floodplains or specific zones), and it enforces county zoning. Onsite septic is permitted by Stillwater County Environmental 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 Stillwater County?

Living in an RV on your own land in Stillwater 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 Stillwater County, Montana?

Land in Stillwater County runs about $1,747 per acre, based on the latest county data.

What is the water situation in Stillwater County?

Stillwater County gets about 18.4" of rain a year, with severe drought in roughly 11.6% of years. On water rights, Stillwater County lies in the Horse Creek Controlled Groundwater Area — Inside the CGWA a completed well may serve domestic/stock use at a maximum 35 gpm not to exceed 1 acre-ft/yr (versus the statewide 10 acre-ft exemption); larger uses need a permit..

How remote is Stillwater County?

A typical private-land location has about 4,402 people within 15 miles and 408,847 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Stillwater compares in Montana

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