Bolthole Index

Sanders County, Montana

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

74Index Score / 100
#6 of 56 in Montana

Unincorporated Sanders County, Montana has no adopted county zoning, and an owner-occupied home with fewer than five dwelling units generally does not need a state building permit unless it serves transient guests.12 County septic permits and well permits come from Sanders County Environmental Health, and driveway approval, floodplain review and rules for buildings rented or leased can also apply.3456

At a glance

Building permit
Most owner-occupied homes are exempt; rental or transient-guest projects may require review26
Zoning
No adopted county zoning regulations in unincorporated Sanders County1
Septic permit
Required through Sanders County Environmental Health73
Well permit
Required before constructing a well8
RV living
No county zoning barrier, but sanitation rules and a waste-disposal plan may apply910
Tiny home
No county zoning restriction in unincorporated areas; sanitation and site rules still apply911
Owner-installed septic
Allowed for a qualifying standard-gravity system after the homeowner passes the installer exam12
Driveway access
County or state encroachment paperwork applies, depending on the road13

Who to call

Septic permits

Sanders County Environmental Health

Well and wastewater-system permits and inspections, plus licensing of wastewater site evaluators and installers.

406-827-6961

1111 Main Street W, Thompson Falls, MT 59873

Also useful

Sanders County Land Services

Subdivision, Buildings for Lease or Rent, floodplain, airport-affected-area, noxious-weed and road-encroachment matters.

406-827-6965

P.O. Box 519, Thompson Falls, MT 59873

Roads & driveways

Sanders County Road Department

Driveway encroachment forms for access from county roads and Montana state highways.

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 Sanders County, Montana?

An owner-occupied residence with fewer than five dwelling units in state jurisdiction is exempt from Montana's building permit unless it serves transient guests2. Farm and ranch buildings and private garages or storage buildings used by the owner outside a business are also exempt from the state permit2, and the state exemption does not remove county septic, well, floodplain or subdivision requirements.14 Montana has nevertheless adopted a uniform statewide building code, and the State Building Codes Bureau handles areas outside certified local programs, including Sanders County15. Covered construction, additions, alterations and repairs need the state permit before work starts and are subject to state inspections216. In unincorporated Sanders County, buildings created for lease or rent have a separate county review path; some require sanitation review and a recorded certificate, while other rental buildings on one tract require governing-body approval6. Vacation and tourist homes are also licensed and inspected through Environmental Health17.

Who handles building and land permits in Sanders County?

Sanders County Land Services is the first call for subdivision, Buildings for Lease or Rent, floodplain, airport-affected-area and road-encroachment matters18. For a project covered by Montana's building-permit rules, the State Building Codes Bureau issues permits and performs required inspections because Sanders County is not listed as a certified local building-code program1516. Sanders County Environmental Health handles well and wastewater permits and inspections319. Environmental Health applications require the applicable information and fees, while the exact fees are set or changed by the county board rather than stated in the regulations2021. The Road Department supplies the appropriate encroachment paperwork for a driveway from a county road or Montana state highway1322.

Does Sanders County have zoning?

Unincorporated Sanders County has no adopted county zoning regulations1. That means county zoning does not impose a minimum dwelling size, minimum lot size, general setback, lot-coverage limit or building-height limit there2324252627. It does not mean every parcel is unrestricted: subdivision, floodplain, airport, wastewater, well and private-covenant limits can still control a site15. Buildings for lease or rent have their own standards, including a ten-foot property-line setback unless the governing body requires more and a fifty-foot height limit2829. Mobile-home parks under those rules also have space-specific coverage limits30. Incorporated Thompson Falls, Plains and Hot Springs are outside the county's Buildings for Lease or Rent rules and may have their own local requirements6.

How do septic and well permits work in Sanders County?

Sanders County requires a permit before installing, modifying, repairing, replacing or increasing use of a wastewater system unless a listed exception applies7. Environmental Health must inspect a permitted system before it is covered, and final approval is required to keep the permit valid31. A homeowner may install a standard-gravity system on the homeowner's own parcel after scoring at least ninety percent on the installer exam, but that route excludes ETA beds, sand mounds and advanced-treatment systems12. Only 4.5% of Sanders County soils lack severe limits for a conventional drain field, so make wastewater feasibility an early purchase contingency32. A new well also needs a county permit before construction8. Structures generating wastewater must use the applicable public connection, compliant treatment system or approved toilet option, and a portable chemical toilet cannot be a permanent wastewater system for a structure3334.

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

County zoning does not bar RV, tiny-home or manufactured-home occupancy in unincorporated Sanders County because the county has no zoning ordinance9. Sanitation rules still apply: camping in one location for thirty days or more outside a licensed campground or RV park may require a compliant waste-disposal plan10. The permit exception for de minimis camping wastewater does not cover wastewater from an RV or another plumbed fixture35. An occupied tiny home must also have an approved wastewater system or another approved toilet facility, and a structure with piped water must meet the county's connection or treatment-system alternatives1133. Rental use changes the answer: buildings created for lease or rent may need county review, and vacation or tourist homes are licensed and inspected617. Ask Land Services about floodplain, airport and rental review, and ask Environmental Health to approve the sanitation plan before moving a dwelling onto the parcel1819. A tiny home used as housing falls under the county's rental-building review if it is offered for lease or rent in unincorporated Sanders County; incorporated Thompson Falls, Plains and Hot Springs are outside that county regulation.36

How do you build a home in Sanders County, Montana, step by step?

  1. Ask Land Services whether the parcel triggers subdivision, floodplain, airport-affected-area or Buildings for Lease or Rent review18.
  1. Determine whether the project is exempt from Montana's state building permit or needs state plan review, permits and inspections216.
  1. Apply to Environmental Health for the well and wastewater approvals; county applications require the applicable information and fees2087.
  1. Use a licensed installer, or qualify to install your own standard-gravity septic system by passing the homeowner exam12.
  1. Complete the county or state driveway-encroachment paperwork that matches the road, including the required site plan for county-road access3722.
  1. Arrange the required septic inspection before covering the system and obtain final approval31.

What should you check before buying land in Sanders County?

Start with wastewater feasibility because only 4.5% of Sanders County soils lack severe limits for a conventional drain field32. Review terrain and clearing needs because only 23.6% of the county is at a slope of 15% or less and 75.3% is wooded3839. Confirm legal and physical access; a new county-road driveway requires encroachment paperwork, a site plan and county approval, while state-highway access uses the state process40. Ask Land Services whether floodplain, airport or subdivision rules affect the parcel, since the absence of zoning does not remove those reviews118. Updated county subdivision regulations took effect October 1, 2026 and replaced the regulations adopted in 202041. More than half of Sanders County—52.4%—is federal land, so verify boundaries and recorded access instead of assuming adjoining open ground belongs to the parcel42.

Watch-outs

  • A building that is exempt from Montana's state permit is not exempt from county septic, well, floodplain, access or rental review27854.
  • Camping in one place for thirty days or more outside a licensed campground or RV park may require a waste-disposal plan, and RV wastewater is not within the de minimis camping exception1035.
  • Only 4.5% of Sanders County soils lack severe limits for a conventional septic drain field, so obtain a site evaluation before committing to a building site32.

Sources

  1. Byrns Minor Subdivision Staff Report, quoted and re-checked
  2. Building Permits, quoted and re-checked
  3. Sanders County Wastewater Treatment Regulations, quoted and re-checked
  4. Land Services, quoted and re-checked
  5. Land Services, quoted and re-checked
  6. Sanders County Buildings for Lease or Rent Regulations, quoted and re-checked
  7. Sanders County Wastewater Treatment Regulations, quoted and re-checked
  8. Sanders County Well Regulations, quoted and re-checked
  9. Montana law on county zoning and building authority
  10. Sanders County Wastewater Regulations, quoted and re-checked
  11. Sanders County Wastewater Treatment Regulations, quoted and re-checked
  12. Sanders County Wastewater Regulations, quoted and re-checked
  13. Road Department | Sanders County, MT, quoted and re-checked
  14. Building Permits — Exemptions, quoted and re-checked
  15. Montana Building Codes Program, quoted and re-checked
  16. Building Permits, quoted and re-checked
  17. Environmental Health | Sanders County, MT, quoted and re-checked
  18. Sanders County Land Services (co.sanders.mt.us)
  19. Sanders County Environmental Health (co.sanders.mt.us)
  20. Administrative Regulations Section 3, quoted and re-checked
  21. Administrative Regulations Section 3, quoted and re-checked
  22. Sanders County Road Department (co.sanders.mt.us)
  23. Byrns Minor Subdivision Staff Report, quoted and re-checked
  24. Byrns Minor Subdivision Staff Report, quoted and re-checked
  25. Byrns Minor Subdivision Staff Report, quoted and re-checked
  26. Byrns Minor Subdivision Staff Report, quoted and re-checked
  27. Byrns Minor Subdivision Staff Report, quoted and re-checked
  28. Sanders County Buildings for Lease or Rent Regulations, quoted and re-checked
  29. Sanders County Buildings for Lease or Rent Regulations, quoted and re-checked
  30. Sanders County Buildings for Lease or Rent Regulations, quoted and re-checked
  31. Sanders County Wastewater Treatment Regulations, quoted and re-checked
  32. 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
  33. Sanders County Wastewater Treatment Regulations, quoted and re-checked
  34. Sanders County Wastewater Regulations, quoted and re-checked
  35. Sanders County Wastewater Regulations, quoted and re-checked
  36. SANDERS COUNTY Buildings for Lease or Rent Regulations, quoted and re-checked
  37. Road Department, quoted and re-checked
  38. Share of land at 15% slope or less: Bolthole Index county data
  39. Wooded share of land: Bolthole Index county data
  40. Road Department | Sanders County, MT, quoted and re-checked
  41. Land Services | Sanders County, MT, quoted and re-checked
  42. Federal land share: Bolthole Index county data

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

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

RuleSanders CountyMineral CountyLake CountyLincoln CountyFlathead CountyMissoula CountyPowell County
Building permitLimitedNot requiredLimitedNot requiredNot requiredRequiredRequired
County zoningNoNoYesYesNoYesYes
Septic permitsCounty Env. HealthCounty Env. Health & PlanningCounty Board of HealthCounty Health Dept.Flathead City-County Health Dept.Missoula City-County Health Dept.Tri-County Env. Health

County locator

Sanders County in Montana

74
County map
Sanders County highlighted among the Montana counties · colored by Index score

How Sanders County scores

Seclusion84100% ev.
Self-Sufficiency45100% ev.
Admin Boringness6990% ev.
Durability48100% 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 →

$463kTypical home
0.5%Property tax
$1,180Land / acre
31.9"Annual rain
12.6% of yrsSevere drought
1.4 / yr (+1.3)Mid-century 100°F days
20.7 daysMid-century dry spell
1.33" (+4.6%)Mid-century 1-day rain
1.35×Wildfire change factor
100%Forward climate coverage
$1,566Home insurance / yr
2.2% / yrInsurance growth
1%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
4,010Radius comparison (15 mi)
5People / sq mi
52.4%Federal land
23.6%Land at 15% slope or less
4.5%Soils rated "not limited" for septic (strict USDA rating)
72,627 acWorkable land screen
75.3%Wooded land
39.4 tonsBiomass / forest ac
43.2°FAvg temp

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Cities and towns in Sanders 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.

Town of Hot Springs · Town of Plains · Thompson Falls

Answers from the rulebook for Sanders County

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

Sanders County rules

  • Building permitLimited

    Buildings for lease or rent subject to the county's Buildings for Lease or Rent Regulations; incorporated Thompson Falls, Plains, and Hot Springs are excluded.

    • The regulations concern buildings created for lease or rent.
    • The first three or fewer nonexempt buildings may require sanitation review and recording of a certificate of approval; all other buildings for lease or rent on one tract require governing-body review and approval.
    • This is not evidence of a general residential building-permit requirement.
    “All other buildings for lease or rent on a single tract of record require review and approval by the governing body, pursuant to the provisions of Section 6.”
  • Owner-builder exemptionConditional

    Homeowner installation of an on-site wastewater treatment system.

    • The homeowner must pass the installer exam with a score of at least 90%.
    • The system must be a standard gravity system; ETA beds, sand mounds, advanced treatment, and similar systems are excluded.
    • The system must be located on the homeowner's parcel.
    • A builder constructing structures for sale, rent, or lease rather than personal residence is not a homeowner.

    installer exam score: >= 90 percent (Homeowner installation)

    “A homeowner may install an on‐site wastewater treatment system under the following conditions: (a) The homeowner passes the installer exam with a score of at least 90%; (b) the wastewater treatment system is a standard gravity system (no ETA beds, sand mounds, advanced treatment, or similar systems); and, (c) the system is located on the parcel owned by the homeowner.”
  • InspectionsLimited

    County review of applications for buildings created for lease or rent.

    • Inspection is authorized during the review process.
    • All site visits may be coordinated in advance and access occurs only after coordination.
    • Failure to provide requested access may delay processing or approval.
    “Submission of a signed application constitutes authorization for representatives of Sanders County and its authorized agents to enter the property for routine monitoring and inspection during the review process.”
  • County-wide zoningAbsent

    County zoning in unincorporated Sanders County.

    • The cited statement is limited to unincorporated areas; incorporated municipalities may have separate rules.
    • Subdivision, floodplain, airport-affected-area, wastewater, and other non-zoning regulations may still apply.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Zoning districts · by state lawNot published

    Unincorporated Sanders County: no county rule sets this, because Sanders County's own reviewed answer confirms it has no county-wide zoning ordinance.

    • Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
    • The cited statement is limited to unincorporated areas; incorporated municipalities may have separate rules.
    • Subdivision, floodplain, airport-affected-area, wastewater, and other non-zoning regulations may still apply.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Minimum dwelling sizeNone

    County zoning minimum-dwelling-size standards in unincorporated Sanders County.

    • The absence is limited to adopted zoning regulations; non-zoning building, health, wastewater, subdivision, or private-covenant requirements may still apply.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Minimum lot sizeNone

    County zoning minimum-lot-size standards in unincorporated Sanders County.

    • Subdivision regulations can impose separate lot standards and must be reviewed for subdivisions.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • SetbacksSpecified

    Buildings for lease or rent subject to county review.

    • The governing body may specifically require a greater setback.

    property-line setback: >= 10 feet (Or as specifically required by the governing body)

    “Buildings, including all above-grade attachments, shall have setbacks of 10 feet or more from the property lines, or as specifically required by the governing body;”
    One more reviewed finding on this topic
    • None — County zoning setback standards in unincorporated Sanders County.
      “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Lot coverageSpecified

    Mobile-home parks subject to county Buildings for Lease or Rent Regulations.

    • The limit is expressed per mobile-home space, not countywide parcel coverage.

    mobile home pad coverage: <= 0.3333333333 space area · total mobile home and roofed accessory coverage: <= 0.6666666667 space area

    “A mobile home pad may not occupy more than one-third (1/3) of the area of its space. The total area occupied by a mobile home and its roofed accessory buildings and structures may not exceed two-thirds (2/3) of the area of a space;”
    One more reviewed finding on this topic
    • None — County zoning lot-coverage standards in unincorporated Sanders County.
      “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Building heightNone

    County zoning building-height standards in unincorporated Sanders County.

    • Airport-affected-area rules may impose separate structure-height controls.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
    One more reviewed finding on this topic
  • Living in an RVLimited

    Camping or RV placement for thirty or more days outside a licensed campground or recreational vehicle park, as addressed by Sanders County wastewater rules.

    • A waste-disposal plan may be required when a tent, recreational vehicle, camper, or other temporary structure is placed for camping in one area for thirty or more days outside a licensed campground or recreational vehicle park.
    • The rule is a sanitation requirement and does not establish a general countywide land-use occupancy permission.

    camping duration: >= 30 days (outside a licensed campground or recreational vehicle park)

    “Camping may require the submittal of a waste disposal plan meeting the requirements of these regulations when a tent, recreational vehicle, camper, or other temporary structure is placed for the purpose of camping in one area for thirty (30) or more days outside of a licensed campground or recreational vehicle park.”
  • Camping on your landLimited

    Temporary camping outside licensed campgrounds or recreational vehicle parks.

    • Camping for thirty or more days in one area may require a waste-disposal plan.
    • De minimis wastewater generated from camping is listed as not requiring a permit, but that exception does not include wastewater from RVs or any other plumbed fixture.

    camping duration: >= 30 days (outside a licensed campground or recreational vehicle park)

    “Disposal of de minimis wastewater generated from camping. This does not include wastewater from RVs or any other plumbed fixture.”
  • Tiny homesLimited

    A tiny home used as a building or unit for permanent or temporary housing, including a unit or space offered for lease or rent, in the unincorporated areas of Sanders County.

    • The regulation applies to all unincorporated areas of Sanders County, excluding the incorporated city of Thompson Falls and the towns of Plains and Hot Springs.
    • The regulation defines a building as a structure or unit of a structure with a roof supported by columns or walls for permanent or temporary housing, and includes multiple spaces for lease or rent on which recreational vehicles or mobile homes will be placed; applicability to a particular tiny home depends on its facts and use.
    • A building created for lease or rent and not served by water or wastewater is exempt when it is one of three or fewer pre-September 1, 2013 buildings on the tract, qualifying lodging subject to the lodging facility use tax (except recreational camping vehicles or mobile home parks), for farming or agricultural purposes, not served by water or wastewater and not leased or rented, or a mini-storage facility with 130 or fewer units.
    • A building created for lease or rent and served by water and wastewater is exempt from all provisions other than sanitation-review subsection 5.D when it is one of three or fewer pre-September 1, 2013 buildings, qualifying lodging subject to the lodging facility use tax (except recreational camping vehicles or mobile home parks), for farming or agricultural purposes, an apartment building with 10 or fewer units, or covered by a notarized recorded declaration that it will not be leased or rented; the declaration runs with the land, binds successors, and may be revoked only by written approval of the landowner and governing body.
    • The first three or fewer non-exempt buildings for lease or rent on a tract require sanitation review and approval by the applicable state or local reviewing authority when required by law, and any approval and conditions must be recorded with the Sanders County Clerk and Recorder. All other buildings for lease or rent on a single tract require review and approval by the Sanders County governing body.
    • An application must be submitted to the administrator with all applicable review fees. The administrator determines completeness within 10 working days; a complete application is approved, conditionally approved, or denied by the Board of County Commissioners within 60 working days, subject to written mutual extension.
    • The governing-body review is conducted at a noticed public meeting with newspaper and mailed notice at least 15 days before the meeting. The notice must include the property description, proposed number and type of uses, and a description of any requested variances.
    • Approval requires findings concerning compliance and impact minimization, adequate water/wastewater/solid-waste facilities, adequate access, adequate emergency medical/fire/law-enforcement services, applicable floodplain compliance, and compliance with applicable state, federal, tribal, licensing, and permitting requirements.
    • For projects subject to Section 6 review, buildings generally must be set back 10 feet or more from property lines, or as specifically required by the governing body, and buildings generally may not exceed 50 feet in height.
    • The 10-foot setback and 50-foot height standards are not absolute: the governing body may grant a variance when land characteristics make strict compliance an undue hardship and the variance is not essential to public welfare and does not nullify the regulations' intent.
    • A variance request must be submitted with the lease-or-rent application with a written statement and supporting evidence; it is reviewed at the noticed public meeting, decided as a separate action before the underlying application, and must satisfy the stated public-health, undue-hardship, public-cost, and zoning-conformance criteria.
    • The regulations do not abrogate prior building permits, subdivision approvals, certificates of occupancy, variances, or other lawful permits issued before October 22, 2025, and do not abrogate other applicable regulations, including private covenants, airport-affected-area regulations, or floodplain regulations.

    effective date: 2025-10-22 · review fee: all fees established for review USD · pre-September 1, 2013 lease-or-rent building exemption threshold: <= 3 buildings per tract (Only where the other listed exemption conditions are met.) · mini-storage exemption threshold: <= 130 units per tract · apartment exemption threshold: <= 10 dwelling units · general building setback: >= 10 feet (The regulation states 'or as specifically required by the governing body'; variance procedure applies.) · building height: <= 50 feet (Variance procedure applies.) · application completeness determination: 10 working days · governing-body decision: 60 working days (May be extended by written mutual agreement.) · public-meeting notice: >= 15 days (Newspaper and mailed notice.)

    “These regulations apply to all lands within the unincorporated areas of Sanders County, excluding the incorporated city of Thompson Falls and towns of Plains and Hot Springs. [...] Building – As defined in Section 76-8-101(1), MCA, a structure or a unit* of a structure with a roof supported by columns or walls for the permanent or temporary housing or enclosure of persons or property or for the operation of a business. [...] Lease or rent – The act of a landowner providing for or otherwise allowing another party to occupy a building or a portion of a building in exchange for financial or other consideration.”
  • Manufactured homes · by state lawUnrestricted

    Unincorporated Sanders County: no county rule sets this, because Sanders County's own reviewed answer confirms it has no county-wide zoning ordinance.

    • Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
    • The cited statement is limited to unincorporated areas; incorporated municipalities may have separate rules.
    • Subdivision, floodplain, airport-affected-area, wastewater, and other non-zoning regulations may still apply.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Accessory dwellings · by state lawUnrestricted

    Unincorporated Sanders County: no county rule sets this, because Sanders County's own reviewed answer confirms it has no county-wide zoning ordinance.

    • Septic, floodplain, subdivision and health rules still apply; cities and towns set their own rules inside their limits.
    • The cited statement is limited to unincorporated areas; incorporated municipalities may have separate rules.
    • Subdivision, floodplain, airport-affected-area, wastewater, and other non-zoning regulations may still apply.
    “There are no adopted zoning regulations within the unincorporated areas of Sanders County.”
  • Who permits septicCounty (with conditions)

    Onsite wastewater and septic regulation in Sanders County.

    • County rules must be no less stringent than applicable state standards.
    • The regulations adopt certain Montana DEQ standards by reference, applying the more stringent rule when discrepancies exist.
    “Permit and inspect installation of wells and wastewater systems”
  • Septic permitRequired

    Installation, modification, repair, replacement, or increased use of wastewater treatment and disposal systems in Sanders County.

    • No permit is required for listed maintenance activities, investigative activities, swimming-pool or spa surface application, de minimis camping wastewater excluding RVs and other plumbed fixtures, certain dry-structure gray water, specified sumps, and qualifying floor drains.
    • Parcels must be recorded with the County Clerk and Recorder before a permit may be issued.
    • The Department shall issue a permit within thirty days after required fees, a complete and accurate application, and other necessary compliance information are submitted, subject to the regulation's additional conditions.

    permit issuance period: <= 30 days (after submission of required fees, a complete and accurate application, and other necessary information demonstrating compliance)

    “No person may install, modify, repair, replace, or increase use of a wastewater treatment and disposal system within Sanders County without first obtaining a permit from the Department, except for activities and systems described in (A)(2) and (A)(3).”
    One more reviewed finding on this topic
    • Required — Installation, modification, repair, replacement, or increased use of wastewater treatment and disposal systems in Sanders County.
      “No person may install, modify, repair, replace, or increase use of a wastewater treatment and disposal system within Sanders County without first obtaining a permit from the Department, except for activities and systems described in (A)(2) and (A)(3).”
  • Septic inspectionRequired

    Permitted wastewater treatment and disposal systems in Sanders County.

    • Inspection is required before covering unless the Department grants specific permission to backfill part of the system.
    • The Department must be notified at least two business days before final inspection.
    • Certified installers may self-inspect only with Department permission when Department personnel cannot inspect within two business days.
    • Final approval is required for the permit to remain valid.

    advance inspection notice: >= 2 business days (Notice before the system is ready for final inspection)

    “Wastewater treatment and disposal systems require an inspection prior to covering the system unless specific permission has been granted by the Department to backfill a portion of the system for a justified reason.”
  • Off-grid sanitationLimited

    Off-grid sanitation and approved toilet facilities for occupied structures in Sanders County.

    • An approved wastewater treatment system or other approved toilet facility is required.
    • Piped-water structures must satisfy the connection or approved-system alternatives in the regulation.
    • Specific portable-toilet and gray-water exceptions have separate conditions.
    “Structures designed and constructed for occupancy by people must maintain a wastewater treatment system or other approved toilet facilities.”
    One more reviewed finding on this topic
    • Limited — Off-grid and alternative wastewater disposal in Sanders County.
      “Portable chemical toilets may not be used as a permanent wastewater system for structures. Portable chemical toilets are not subject to permitting requirements, but must meet horizontal setback requirements of a sealed component.”
  • Well permitRequired

    Construction of wells in Sanders County.

    • Applications must include owner/property information, an approved lot layout or site plan, intended use, well diameter, the Board-established fee, and any required authorization for an isolation zone crossing neighboring property.
    • The permit expires if the well is not installed, inspected, and approved within one year; one one-year extension may be granted if stated conditions are met.
    • Starting construction before a valid permit triggers a fee three times the application fee, effective 90 days after the regulation's effective date.

    permit validity: 1 year (One extension of one year may be granted if conditions are met) · unpermitted-construction fee: 3 times the permit application fee (Applies when construction starts before a valid permit)

    “A person may not construct a well within Sanders County without first obtaining a permit from the Department.”
  • Mandatory utility hookupConditional

    Structures generating wastewater in Sanders County.

    • Unless excluded, a structure generating wastewater must connect to a public wastewater system under the applicable Montana administrative rule.
    • Structures served by piped water must connect to public wastewater, use a compliant wastewater treatment system, or have an approved toilet facility within 200 feet, as applicable.

    approved toilet facility distance: <= 200 feet (Existing wastewater treatment system or approved toilet facilities)

    “Unless excluded, a person owning real property, with a structure that generates wastewater must connect to a public wastewater treatment system in accordance with ARM 17.36.328 (1) or ARM 17.36.914 (6), whichever is applicable to the specific parcel.”
  • Subdividing landRegulated (with conditions)

    Subdivision and land-development submittals in Sanders County.

    • The county page states that updated subdivision regulations take effect October 1, 2026 and replace regulations adopted in 2020.
    • Subdivision review includes applicable floodplain, health, road, and other regulatory requirements.
    • Exempt divisions must comply with the Montana Subdivision and Platting Act.

    new subdivision regulations effective date: 2026-10-01 (replace regulations adopted in 2020)

    “The Sanders County Board of County Commissioners has adopted updated Sanders County Subdivision Regulations. The new regulations will take effect on October 1, 2026, replacing the regulations adopted in 2020.”
    One more reviewed finding on this topic
    • Regulated (with conditions) — Subdivision review and regulation in Sanders County.
      “The new regulations will take effect on October 1, 2026, replacing the regulations adopted in 2020.”
  • Driveway accessRequired

    Driveways accessed from a Sanders County road in the county jurisdiction.

    • A driveway encroachment must be completed whenever a driveway is accessed from a county road.
    • The driveway encroachment application requests permission to encroach upon County right of way and requires an attached site plan showing the relationship of the drive approach to the county roadway and mailbox placement.
    • The site plan must show physical features including hills, curves, drainage ditches, and possible sight-distance obstructions so county staff can determine suitability.
    • The landowner accepts responsibility for upkeep and maintenance of the approach, including repair or replacement of any present or future culvert.
    • The application may be denied if the property already has an existing means of access that does not require a new encroachment onto a County Road.
    • The completed work is subject to inspection and approval by the Sanders County Road Foreman.
    • The form is marked Revised 07/29/2025; this is not treated as an effective date.
    • For driveways accessing Montana state highways, the county page identifies a separate State of Montana encroachment form and states that the Montana Department of Transportation maintains Montana highways.
    “Driveway Encroachments must be completed whenever a driveway is accessed from a county road or State Highway to ensure public safety and prevent unnecessary degradation of county- and state-maintained roads and highways.”
    4 more reviewed findings on this topic
    • Required — Driveway access from a Sanders County road or a Montana state highway.
      “Driveway Encroachments must be completed whenever a driveway is accessed from a county road or State Highway to ensure public safety and prevent unnecessary degradation of county- and state-maintained roads and highways.”
    • Required — Driveways accessing county roads in Sanders County, including residential, commercial, and field approaches.
      “Driveway Encroachments must be completed whenever a driveway is accessed from a county road or State Highway to ensure public safety and prevent unnecessary degradation of county- and state-maintained roads and highways.”
    • Required — Driveway and subdivision road approaches onto county roads in subdivisions governed by the Sanders County Subdivision Regulations.
      “All driveway and subdivision road approaches onto county roads shall be permitted through the County and designed to prevent stormwater from draining on the surface of the county road.”
    • Limited — Driveway and road access in county-reviewed subdivisions and county road encroachment matters.
      “Administer the Sanders County Subdivision Regulations, Buildings For Lease or Rent Regulations, Floodplain Regulations, Airport Affected Area Regulations, Subdivision Noxious Weed Management Plan, and Road Encroachment Permits”
  • Building in a floodplainLimited

    Development in regulated floodplain areas of Sanders County.

    • Land Services administers county floodplain regulations.
    • Parcel-specific floodplain location and permit requirements were not determined from the reviewed sources.
    “Administer the Sanders County Subdivision Regulations, Buildings For Lease or Rent Regulations, Floodplain Regulations, Airport Affected Area Regulations, Subdivision Noxious Weed Management Plan, and Road Encroachment Permits”
    One more reviewed finding on this topic
  • Short-term rentalsLimited

    Vacation or tourist homes and related short-term lodging operations regulated through Sanders County Environmental Health.

    • The county Environmental Health page states that vacation/tourist homes are licensed and inspected.
    • This source does not establish the full land-use or tax treatment of every short-term rental.
    “License and inspect: Food Service Establishments; Food Manufacturers; Mobile Food Carts; Public Accommodations; Trailer Parks and Campgrounds; Pools and Spas; Vacation/Tourist Homes”
    One more reviewed finding on this topic
    • Limited — Vacation/tourist homes and related short-term lodging facilities regulated by Sanders County Environmental Health.
      “License and inspect: Food Service Establishments; Food Manufacturers; Mobile Food Carts; Public Accommodations; Trailer Parks and Campgrounds; Pools and Spas; Vacation/Tourist Homes”
  • Permit feesVariable (with conditions)

    County environmental-health permit, inspection, variance, and related service fees.

    • Fees are established or changed by the Board; the cited regulations do not provide the numeric fee schedule.
    • Wastewater applications and field work requiring a fee require all fees to be paid; application fees are non-refundable.
    • Well applications require the appropriate Board-established fee.
    “The Board may adopt fees that are fair and reasonable for permit applications, Department services, tests, or certifications established by this Code. Fees may be adopted or changed at any regularly scheduled meeting of the County Commissioners providing that the action is scheduled on the agenda and public comment is allowed.”
  • Permit processPublished (with conditions)

    County wastewater and well permit processes.

    • Wastewater applications are available from Environmental Health and require applicable information and fees.
    • Well applications must be made by the property owner or authorized representative on Department forms and include the stated site-plan, use, diameter, fee, and authorization information.
    • Wastewater permits are subject to expiration, denial, appeal, variance, and emergency-permit rules.
    “Applications for permits are available at the Department located at 1111 Main Street in Thompson Falls. Applicants may obtain a permit from the Department upon compliance by the applicant with the application requirements and provisions of the applicable regulation and payment of fees.”
    One more reviewed finding on this topic
    • Partial — County land-development and subdivision submittal processes in Sanders County.
      “For questions about the subdivision regulations or subdivision review process, please contact the Sanders County Land Services Department.”

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.”
    2 more reviewed findings on this topic
    • Adopted — Residential and commercial building-code administration in Sanders County, including areas outside certified local building-code jurisdictions
      “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.”
  • 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.”
  • Agricultural exemptionAvailable (with conditions)

    State building-permit exemptions for farm and ranch buildings in Montana, including the state-jurisdiction portion of Sanders County.

    • The exemption is stated for the State's jurisdiction and does not establish exemption from county, municipal, subdivision, wastewater, floodplain, or other applicable requirements.
    • Mining, petroleum, certain residential, and private-garage/storage exemptions are separate exemptions listed on the same page.
    “In the State's jurisdiction, state law exempts the following from the need to obtain state building permits: 1. farm and ranch buildings”
    One more reviewed finding on this topic
    • Available (with conditions) — State building-permit exemptions for farm and ranch buildings in Montana.
      “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.”
  • 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.

  • Local zoning — Aggregate local zoning within Sanders County, including incorporated municipalities and any other local jurisdictions.

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 Sanders County

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

Closed to new supply

New water supply here generally requires a permit, an offset, or buying an existing right — a household well is not automatic.

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 Sanders County, Montana

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

Sanders County scores 74/100 on the Bolthole Index, a strong county profile. Its strengths: sparse surroundings — about 4,010 people within 15 miles and a stronger property-autonomy legal backdrop.

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

Sanders County requires a building permit only in limited cases (such as floodplains or specific zones), and it has no county-wide zoning. Onsite septic is permitted by Sanders County Environmental Health. 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 Sanders County?

Living in an RV on your own land in Sanders 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. A tiny home is limited to specific cases. Confirm with the county before relying on it.

How much does land cost in Sanders County, Montana?

Land in Sanders County runs about $1,180 per acre, based on the latest county data.

What is the water situation in Sanders County?

Sanders County gets about 31.9" of rain a year, with severe drought in roughly 12.6% of years. On water rights, Sanders County lies in the BNSF Paradise Railyard Controlled Groundwater Area — Contamination-driven CGWA near Paradise; no wells for any purpose except monitoring may be installed..

How remote is Sanders County?

A typical private-land location has about 4,010 people within 15 miles and 730,040 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Sanders compares in Montana

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