Bolthole Index

Sweet Grass County, Montana

Building permits, zoning and septic rules in Sweet Grass County, Montana

66Index Score / 100
#23 of 56 in Montana

A single-family home in unincorporated Sweet Grass County, Montana generally does not need a state building permit unless a local jurisdiction requires one1. Big Timber requires a municipal land-use permit for covered construction, while county Planning administers county zoning districts and floodplain permits; Sweet Grass County Environmental Health handles septic permits throughout the county2345.

At a glance

Building permit
A single-family home generally needs no state building permit, but local zoning approval may apply1
Zoning
Varies by parcel; Big Timber is zoned, while county-administered districts may apply elsewhere36
Septic permit
Required through Sweet Grass County Environmental Health75
RV living
Countywide private-land occupancy rule not confirmed; ask City-County Planning about the parcel8
Tiny home
No countywide occupancy rule confirmed; Big Timber district minimums may apply910
Owner-builder
A qualifying owner may avoid contractor registration and may personally do plumbing for a personal-use home without a state plumbing permit1112
Floodplain
Development in a mapped flood-hazard area must be reviewed13
County-road access
Right-of-way construction requires an encroachment permit before work starts14

Who to call

Building permits

Montana Building Codes Program

State building-permit questions and applications for non-exempt projects; separate state electrical, plumbing and mechanical permits may apply

(406) 841-2056

buildingcodes@mt.gov

301 South Park Ave., Floors 4 and 5, Helena, MT 59620

Online permits →

Zoning

Sweet Grass County City-County Planning Office

Zoning, land-use permits, subdivision review, rural addressing and floodplain administration

(406) 932-5470

pcdringman@sgcountymt.gov

515 Hooper Street, Big Timber, MT 59011

Septic permits

Sweet Grass County Environmental Health Department

Sweet Grass County septic regulations, applications and installer information

406-366-0807

mspry@sgcountymt.gov

115 West 5th Avenue, Big Timber, MT 59011

Roads & driveways

Sweet Grass County Road & Bridge Department

Encroachment permits for construction work in county roads, streets, alleys and thoroughfares

(406) 932-5140

sgroads@sgcountymt.gov

291 Centennial Drive, Big Timber, MT 59011

Contact details are copied from each office’s official page and were checked against it on October 12, 2026.

Off-grid gear

Going off-grid in Sweet Grass 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 Sweet Grass County, Montana?

A single-family residence in Sweet Grass County generally does not need a state building permit unless it sits inside a local-government jurisdiction that requires one by ordinance or resolution1. State law also exempts residential buildings with fewer than five dwelling units unless they serve transient guests, along with specified farm and ranch buildings and owner-use private garages and storage buildings15. Big Timber is different: erecting, moving, adding to, or structurally altering a building in its zoning jurisdiction requires a land-use permit and compliance with the zoning district unless the ordinance provides an exemption; internal remodeling does not require that land-use permit216. Sweet Grass County Environmental Health still issues septic permits for addresses inside and outside Big Timber5. Separate state electrical, plumbing, or mechanical permits may apply even when no state building permit is required17. Ask City-County Planning to identify the parcel's zoning jurisdiction before relying on an exemption8.

Who issues building permits in Sweet Grass County?

For local land-use approval in Sweet Grass County, City-County Planning at 515 Hooper Street in Big Timber, (406) 932-5470 is the first local call for zoning approval8. Planning administers land-use permits in county-administered zoning areas, but the steps and governing body vary by parcel and application18. Montana's Building Codes Program handles covered state building permits and questions about state electrical, plumbing, or mechanical permits at (406) 841-2056 or buildingcodes@mt.gov1920. A covered state project requires plans and an application; the state plan-review fee is 35% of the building-permit fee2122. Sweet Grass County Environmental Health issues septic permits, Planning handles floodplain permits, and Road & Bridge handles county-right-of-way encroachment permits23824.

Does Sweet Grass County have zoning?

Zoning in unincorporated Sweet Grass County varies by parcel; City-County Planning administers city-county zoning and citizen-initiated districts3. Big Timber's published districts and dimensional standards are municipal rules, not countywide standards for rural land25. Big Timber's R-S district requires a 1-acre lot, R-1 requires 8,400 square feet, and R-2 and R-3 require 6,300 square feet for a single-family lot; additional-unit and apartment rules differ26. Maximum principal and accessory building coverage is 15% in R-S, 30% in R-1, 40% in R-2, and 50% in R-327. Big Timber's minimum dwelling areas are 1,000 square feet in R-S, 700 in R-1 and R-2, and 500 in R-310. In Big Timber's R-3 district, a principal building needs an 8-foot side yard and a front yard of 20 feet with front-yard parking or 15 feet without it28. Ask Planning for the parcel's district and recorded subdivision conditions before designing a home829. County Environmental Health handles septic permits inside and outside Big Timber5.

How do septic permits work in Sweet Grass County?

Sweet Grass County requires onsite wastewater approval for a new system, a repair or replacement, an upgrade or expansion, and a connection to an existing system7. Environmental Health provides the county septic regulations, permit application, and licensed-installer information23. A permit is not issued until the required documentation has been received and approved, and the County Sanitarian or authorized health officials may inspect or investigate an onsite system for compliance730. Montana DEQ separately reviews sanitation for covered subdivisions, but a Certificate of Subdivision Approval does not replace the local drainfield permit3132. Site conditions deserve early attention: only about 9.5% of Sweet Grass County soils are rated without severe limits for a conventional septic drain field, so obtain a site evaluation before fixing a house location or purchase budget33.

Can you live in an RV or tiny home in Sweet Grass County?

We could not confirm a general Sweet Grass County rule for living long-term in an RV on private land, temporary camping on private land, or tiny-home occupancy. The answer depends first on parcel location because Big Timber and county-administered zoning districts can have different land-use rules334. A tiny home in Big Timber must meet the applicable district standard; residential minimum floor areas range from 500 to 1,000 square feet10. Ask the Planning Office to confirm the parcel's district and allowed residential use before moving an RV or tiny home onto the property8. Sweet Grass County Environmental Health still handles septic approval: new systems and connections to existing systems require county approval723.

Building a home in Sweet Grass County: the steps, in order

  1. Ask City-County Planning to identify the parcel's zoning jurisdiction and whether zoning approval or subdivision review is required829.
  1. Ask the Montana Building Codes Program whether the project needs a state building permit and which electrical, plumbing, or mechanical permits apply151720.
  1. Apply to Sweet Grass County Environmental Health for a septic permit before installing, replacing, expanding, or connecting to an onsite system723.
  1. Apply through Planning for floodplain review before development in a designated flood-hazard area; covered work includes new construction, additions, excavation, fill, roads, and manufactured-home placement or replacement358. The county's mapped-floodplain review fee is $1504.
  1. Apply to Road & Bridge for an encroachment permit before construction in a county right-of-way; the fee is $75, plus a Clerk and Recorder filing fee of $7 per page1436. The county encroachment application requires a dimensioned map or drawing and a weed-control plan, followed by a public meeting for review and vote; allow up to two weeks for approval or denial37. For access to a state highway, apply to the Montana Department of Transportation for an approach permit or right-of-way agreement38.

What should you check before buying land in Sweet Grass County?

Start with wastewater feasibility because only about 9.5% of Sweet Grass County soils are rated without severe limits for a conventional drain field33. Ask Environmental Health about the site evaluation and septic-permit process before treating a proposed homesite as buildable237. For a new well, Montana requires either a water-use permit or qualification for the groundwater permit exception3940. Next, have Planning identify zoning, recorded subdivision constraints, and mapped floodplain status813. Confirm access because county right-of-way work requires an encroachment permit, while a state-highway approach follows the state process1438. About 63.5% of county land has a slope of 15% or less41. The effective property-tax rate is about 0.5%, the median annual property-tax bill is about $1,452, and the typical home-insurance premium is about $2,077 per year424344.

Watch-outs

  • A small home may be exempt from the state structural building permit while still needing local land-use approval and separate electrical, plumbing, or mechanical permits151745.
  • Only about 9.5% of Sweet Grass County soils are rated without severe limits for a conventional drain field, so settle septic feasibility before committing to the homesite33.
  • Private-land RV living, temporary camping, and tiny-home occupancy could not be confirmed; ask City-County Planning before relying on any of them8.
  • Montana's contractor-registration exemption does not waive building permits, zoning approval, septic permits, or trade permits, although a homeowner who personally installs plumbing in a personal-use residence may qualify for the state plumbing-permit exemption1112.

Sources

  1. bsd.dli.mt.gov, quoted and re-checked
  2. Big Timber: Big Timber Zoning Ordinance, Chapter 23 (Sweet Grass County), quoted and re-checked
  3. City of Big Timber Zoning, quoted and re-checked
  4. Floodplain | Sweet Grass County Montana, quoted and re-checked
  5. Sweet Grass County Forms/Permits (2026 county census)
  6. sgcountymt.gov, quoted and re-checked
  7. Onsite Wastewater Treatment System Permit Application, quoted and re-checked
  8. Sweet Grass County City-County Planning Office (sgcountymt.gov)
  9. Planning, quoted and re-checked
  10. City of Big Timber Title 11 Zoning Regulations, quoted and re-checked
  11. Montana Code Annotated, Title 37, Chapter 45, Construction Contractors (Montana statewide rule), quoted and re-checked
  12. Plumbing Permits | Montana Building Codes Program, quoted and re-checked
  13. Floodplain, quoted and re-checked
  14. Encroachment, quoted and re-checked
  15. Building Permits (Montana statewide rule), quoted and re-checked
  16. City of Big Timber Zoning, quoted and re-checked
  17. Building Permits (Montana statewide rule), quoted and re-checked
  18. Planning, quoted and re-checked
  19. Montana Building Codes Program, quoted and re-checked
  20. Montana Building Codes Program (bsd.dli.mt.gov)
  21. bsd.dli.mt.gov, quoted and re-checked
  22. bsd.dli.mt.gov, quoted and re-checked
  23. Sweet Grass County Environmental Health Department (sgcountymt.gov)
  24. Sweet Grass County Road & Bridge Department (sgcountymt.gov)
  25. City of Big Timber Zoning, quoted and re-checked
  26. City of Big Timber Title 11 Zoning Regulations, quoted and re-checked
  27. City of Big Timber Title 11 Zoning Regulations, quoted and re-checked
  28. City of Big Timber Zoning Ordinance, quoted and re-checked
  29. Planning, quoted and re-checked
  30. Onsite Wastewater Treatment System Permit Application, quoted and re-checked
  31. Engineering Infrastructure & Subdivisions (Montana statewide rule), quoted and re-checked
  32. Engineering Infrastructure & Subdivisions (Montana statewide rule), quoted and re-checked
  33. 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
  34. Planning | Sweet Grass County Montana, quoted and re-checked
  35. Stream Permitting, quoted and re-checked
  36. Floodplain, quoted and re-checked
  37. Encroachment, quoted and re-checked
  38. Approach Manual for Landowners and Developers (Montana statewide rule), quoted and re-checked
  39. Exempt Well Updates and Information (Montana statewide rule), quoted and re-checked
  40. Exempt Well Updates and Information (Montana statewide rule), quoted and re-checked
  41. Share of land at 15% slope or less: Bolthole Index county data
  42. Effective property tax rate: Bolthole Index county data
  43. Median property tax bill: Bolthole Index county data
  44. Typical home insurance premium: Bolthole Index county data
  45. bsd.dli.mt.gov (2026 county census)

Written October 12, 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 4 of its 6 neighbors, Sweet Grass County requires a building permit only in limited cases.

RuleSweet Grass CountyPark CountyStillwater CountyCarbon CountyWheatland CountyGolden Valley CountyGallatin County
Building permitLimitedNot requiredLimitedNot requiredNot requiredNot requiredLimited
County zoningYesYesYesYesNot publishedNot publishedYes
Septic permitsCounty Env. HealthCounty Env. Health Dept.County Env. Health Dept.County Env. Health Dept.County Env. HealthCounty SanitarianGallatin City-County Health Dept.

County locator

Sweet Grass County in Montana

66
County map
Sweet Grass County highlighted among the Montana counties · colored by Index score

How Sweet Grass County scores

Seclusion88100% ev.
Self-Sufficiency37100% ev.
Admin Boringness5690% ev.
Durability43100% ev.
Property Autonomy83100% ev.
Carry Cost7696% 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 →

$495kTypical home
0.5%Property tax
$1,499Land / acre
19.5"Annual rain
9.9% of yrsSevere drought
1.8 / yr (+1.7)Mid-century 100°F days
18.2 daysMid-century dry spell
1.23" (+5.8%)Mid-century 1-day rain
1.28×Wildfire change factor
100%Forward climate coverage
$2,077Home insurance / yr
0.6% / yrInsurance growth
0.38%Nonrenewal rate
single ZIP shrunk to state medianInsurance basis
312,278People within 2 hr
2,350Radius comparison (15 mi)
2People / sq mi
24.9%Federal land
63.5%Land at 15% slope or less
9.5%Soils rated "not limited" for septic (strict USDA rating)
93,386 acWorkable land screen
28%Wooded land
21.1 tonsBiomass / forest ac
43°FAvg temp

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Cities and towns in Sweet Grass 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 Sweet Grass County

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

Sweet Grass County rules

  • Building permitLimited

    Residential construction in Sweet Grass County, especially projects within the city-county zoning jurisdiction.

    • The state FAQ says a single-family residence does not require a building permit unless it is inside a local government jurisdiction that requires one by ordinance or resolution.
    • County land-use permits may apply within the city-county zoning jurisdiction.
    “A building permit is not required for a single family residence, unless you live inside a local government's jurisdiction, which requires the permit by ordinance or resolution.”
  • Local zoningVaries (with conditions)

    Aggregate local zoning across Sweet Grass County, including municipal zoning and county-administered city-county or citizen-initiated zoning areas.

    • The conclusion aggregates different local zoning authorities and areas; the county does not administer every municipal ordinance.
    • The City of Big Timber is comprehensively zoned according to the official county planning page.
    • County planning materials identify city-county zoning and citizen-initiated zoning districts, but do not establish uniform zoning coverage for all rural parcels.
    “All of the land in the City of Big Timber is zoned and subject to land development regulations.”
    One more reviewed finding on this topic
    • Varies (with conditions) — Aggregate of local zoning in Sweet Grass County, including county/city-county zoning and Big Timber municipal zoning.
      “All of the land in the City of Big Timber is zoned”
  • Zoning districtsPartial

    Published zoning-district information for the City of Big Timber and county-administered city-county zoning areas.

    • The county planning page describes city-county zoning and citizen-initiated zoning districts; the opened zoning page specifically identifies the City of Big Timber zoning ordinance and district requirements.
    • No complete countywide parcel-by-parcel district map was established from the opened pages.
    “The Planning Office is responsible for administering and enforcing the City of Big Timber Zoning Ordinance. The Zoning Regulations outline the requirements associated with each district and define the designated zoning districts.”
  • Septic permitRequired

    New, repair/replacement, upgrade/expansion, and connect-to-existing onsite wastewater systems.

    • The official application lists these permit categories: new, repair/replacement, upgrade/expansion, and connect to existing.
    • Systems must be designed and constructed under the cited Montana administrative rules, DEQ Circular DEQ 4, subdivision rules, and Sweet Grass County onsite wastewater regulations.
    “A permit will not be issued until all necessary documentation has been received and approved by this office”
  • Septic inspectionLimited

    Inspection and investigation of onsite wastewater systems by the County Sanitarian or authorized health officials.

    • The authorization is for inspection and investigation to determine compliance with Park County and Montana regulations as stated on the form; the form does not establish that every system receives the same inspection schedule.
    “the County Sanitarian and/or members of the Park County Board of Health”
  • Subdividing landRegulated (with conditions)

    Subdivision and related land divisions in Sweet Grass County, including applicable Big Timber-area subdivision review.

    • The Planning Department reviews proposed subdivisions, certain exemptions, certificates of survey, boundary relocations, and annexation.
    • Subdivision regulations, health-department regulations, and zoning regulations apply to each lot.
    • Lots must contain a satisfactory building site and conform to applicable regulations.
    • The subdivision process includes pre-application, preliminary-plat, final-plat, planning-board, public-hearing, and governing-body coordination as applicable.
    “This Department administers subdivision regulations, subdivision exemptions and surveys”
  • Driveway accessLimited

    Construction work in a county road, street, alley, or thoroughfare, including access-related encroachment work.

    • An encroachment permit is required before starting construction work of any nature in the county right-of-way.
    • A bond may be required; the application requires a map or drawing with dimensions and a weed-control plan.
    “construction work of any nature in any county road”
  • Building in a floodplainRequired

    Development on lands within mapped 100-year floodplains in Sweet Grass County.

    • The regulations apply only to lands shown on maps or other documents as within a mapped 100-year floodplain.
    • The floodplain ordinance was stated to be effective May 18, 2015.
    • The page states the review fee was increased to $150.

    review fee: 150 USD

    “Development within the designated flood hazard areas must be reviewed to determine exemptions from or compliance with floodplain regulations or need for a floodplain permit.”
    2 more reviewed findings on this topic
    • Required — Development in mapped 100-year floodplain areas within Sweet Grass County.
      “Development within the designated flood hazard areas must be reviewed”
    • Required — Development in designated Special Flood Hazard Areas and regulated floodplains in Sweet Grass County.
      “Any development including, but not limited to, placement of fill, roads, bridges, culverts, transmission lines, irrigation facilities, storage of equipment or materials, and excavation; new construction/development, placement, or replacement of manufactured homes; and new construction, additions, or substantial improvements to residential and commercial buildings.”
  • Permit feesPublished (with conditions)

    Published fees for identified Sweet Grass County permits, including floodplain and county-road encroachment permits.

    • The floodplain page states the review fee was increased to $150 under the ordinance effective May 18, 2015.
    • The county encroachment page lists an encroachment permit fee of $75 and a Clerk and Recorder filing fee of $7 per page.

    floodplain review fee: 150 USD · encroachment permit fee: 75 USD · Clerk and Recorder filing fee: per 7 USD (per page)

    “The new Floodplain Ordinance have been adopted and are effective May 18th, 2015. With the new ordinance the review fee has been increased to $150.”
  • Permit processPartial

    Planning and land-use permit processes in Sweet Grass County.

    • The county planning department administers land-use permits within the city-county zoning area and reviews activities subject to local review, applicable plans, and state law.
    • Specific application steps and requirements vary by permit and governing body.
    “The City-County Planning Department is responsible for land use planning activities that are subject to local review, applicable plans and state law, as it is enforced through local planning departments.”
    One more reviewed finding on this topic
    • Published (with conditions) — County encroachment permits and identified planning/floodplain review processes.
      “A public meeting will be posted on the commissioners agenda for review and vote.”
  • County-wide zoningPresent

    The City-County Planning Department administers zoning regulations and land use permits within the city-county zoning jurisdiction (centered on Big Timber), though much rural land is not comprehensively zoned.

    Sweet Grass County Planning ↗Scouted from the county site, not yet independently re-checked

Montana rules that apply here

  • Owner-builder exemptionConditional

    Owner-performed plumbing installation in a residence within Montana state plumbing jurisdiction.

    • 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 or intended as a rental property.
    • Certified local governments may enforce plumbing code within their jurisdictional areas, so local requirements may apply instead of the state rule.
    “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”
    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 — State building code applicable to residential and commercial buildings in areas under the Montana Building Codes Program, including non-certified Sweet Grass County areas.
      “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.”
  • 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.”
  • Living in an RVLimited

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

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

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

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

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

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

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

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

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

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

    Montana statewide sanitation and septic regulation, including subdivision sanitation review and drainfield permitting.

    • Montana DEQ administers subdivision sanitation review for covered divisions of land and related facilities.
    • The drainfield permit is administered by the local health department even when a Certificate of Subdivision Approval exists.
    “The DEQ Subdivision Program reviews divisions of land comprising less than 20 acres [...] This review is limited to sanitation facilities, including the water supply, sewage disposal, solid waste disposal, and storm drainage systems. [...] Yes, even thought you have a COSA, a drainfield permit is still required by the local health department.”
  • Well permitLimited

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

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

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

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

Inside cities and towns in Sweet Grass County

Municipal rules found while researching the county. They apply inside that city or town, not to unincorporated land.

  • Building permitLimited

    Buildings, structures, and land uses within the City of Big Timber zoning jurisdiction.

    • Internal remodeling projects do not require a Land Use Permit.
    • Buildings or structures that are erected, moved, added to, or structurally altered must be properly permitted unless exempted by the ordinance.
    • A land-use change requires a valid Land Use Permit.
    • The permit authorizes only the use, arrangement, and construction shown in approved plans.
    • The ordinance states that permits expire if work has not commenced within 180 days, or if work is suspended or abandoned for 120 days.

    land use permit fee: 10 USD

    “A permit is required when a building, structure or land will be used or occupied, and no building, structure or part thereof shall be erected, constructed, reconstructed, moved or structurally altered unless it is in conformance with all of the regulations for the district in which it is located. An internal remodeling project does not require a Land Use Permit.”
  • Zoning districtsPublished

    Published Big Timber zoning districts and their bulk requirements.

    • The ordinance's Table 4.1 covers R-S, R-1, R-2, R-3, HB, ICC, CBD, M-I, and PLI districts.
    • The standards are municipality-specific and should not be treated as countywide standards.
    “For the purpose of this title, the City of Big Timber and portions of its extra-territory are hereby divided and classified into the following:”
    One more reviewed finding on this topic
    • Published (with conditions) — Zoning districts within the City of Big Timber.
      “The Zoning Regulations outline the requirements associated with each district”
  • Minimum dwelling sizeSpecified

    Dwelling units in Big Timber zoning districts.

    • Requirements vary by district.
    • R-1 and R-2 require 700 square feet per dwelling unit.
    • R-3 requires 500 square feet per dwelling unit.
    • The ordinance table lists R-S at 1,000 square feet.

    R-S minimum floor area: 1000 square feet · R-1 minimum floor area: 700 square feet · R-2 minimum floor area: 700 square feet · R-3 minimum floor area: 500 square feet

    “R-S 1 ac. 125’ 15% 1,000 s.f. 25’ 20’ behind principal bldg. 8’ 28’ [...] R-1 Low density 8,400 s.f. 60’ 30% 700 s.f. [...] R-2 Medium density [...] 40% 700 s.f. [...] R-3 High density [...] 50% 500 s.f.”
  • Minimum lot sizeSpecified

    Lots in Big Timber zoning districts.

    • Requirements vary by district.
    • R-S requires 1 acre.
    • R-1 requires 8,400 square feet.
    • R-2 and R-3 require 6,300 square feet for single-family lots, with additional-unit and apartment rules as stated in Table 4.1.

    R-S minimum lot area: 1 acre · R-1 minimum lot area: 8400 square feet · R-2 minimum single-family lot area: 6300 square feet · R-3 minimum single-family lot area: 6300 square feet

    “R-S 1 ac. [...] R-1 Low density 8,400 s.f. [...] R-2 Medium density 6,300 s.f. for single-family. [...] R-3 High density 6,300 s.f. for single-family.”
  • SetbacksSpecified

    Residential development in the R-3 Residential High Density District of the City of Big Timber.

    • The ordinance applies within the City of Big Timber zoning jurisdiction.
    • A corner lot must also comply with Chapter 14 setbacks.
    • The ordinance identifies front-yard alternatives depending on whether front-yard parking is provided.
    • Accessory structures have separate dimensional limits stated in the yard provisions.

    front yard with front-yard parking: 20 feet · front yard without front-yard parking: 15 feet · rear yard behind principal structure: 20 feet · rear yard behind garage opening toward alley: 10 feet · rear yard behind garage opening toward street or side yard: 2 feet · rear yard behind storage shed not greater than 144 square feet: 2 feet · side yard next to principal structures: 8 feet · side yard next to storage sheds not greater than 144 square feet: 5 feet · side yard next to garage opening toward street: 10 feet

    “11-8-6: YARDS: Every lot shall have the following yards: (Ord. 454, 6-19-2000) Front yard 20 feet with front yard parking 15 feet without front yard parking Rear yard 20 feet behind principal structure 10 feet behind garage that opens toward alley 2 feet behind garage that opens toward street or side yard 2 feet behind storage shed not greater than 144 sq. feet Side yard 8 feet next principal structures 5 feet next to storage sheds not greater than 144 sq. feet 10 feet next to garage that opens toward street Corner lot See Chapter 14 of this title for setbacks.”
  • Lot coverageSpecified

    Principal and accessory building coverage in Big Timber zoning districts.

    • Maximum coverage varies by district.
    • R-S has 15% maximum coverage, R-1 has 30%, R-2 has 40%, and R-3 has 50%.

    R-S maximum lot coverage: 15 percent · R-1 maximum lot coverage: 30 percent · R-2 maximum lot coverage: 40 percent · R-3 maximum lot coverage: 50 percent

    “R-S 1 ac. 125’ 15% [...] R-1 Low density 8,400 s.f. 60’ 30% [...] R-2 Medium density [...] 40% [...] R-3 High density [...] 50%”

Still unanswered

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

  • Building height — Building-height requirements in Sweet Grass County.
  • Camping on your land — Temporary camping on private land in Sweet Grass County.
  • Tiny homes — Tiny-home occupancy in Sweet Grass County.
  • Off-grid sanitation — Off-grid sanitation systems in Sweet Grass County.
  • Mandatory utility hookup — Water or sewer connection requirements for development in Sweet Grass County.
1 more unanswered
  • Agricultural exemption

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

Water rights & wells in Sweet Grass County

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

Over-appropriated / declining

The aquifer here is over-appropriated and declining. A domestic well is usually still permit-exempt, but long-term supply is a genuine risk.

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) ↗
  • Yellowstone Compact Controlled Groundwater Areapartial of county

    NPS-Montana Compact CGWA covering drainages north/west of Yellowstone to protect the park's geothermal/water resources; new groundwater appropriations of any size require a DNRC permit (the 35-gpm exempt-well basis is suspended).

    Montana DNRC — Basin Closures and Controlled Ground Water Areas ↗

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 Sweet Grass County, Montana

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

Sweet Grass County scores 66/100 on the Bolthole Index, a strong county profile. Its strengths: deep seclusion — about 2,350 people within 15 miles and a stronger property-autonomy legal backdrop. Watch-outs: thin water margin (19.5″/yr rainfall).

Do you need a building permit in Sweet Grass County, Montana?

Sweet Grass 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 Sweet Grass 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 Sweet Grass County?

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

Land in Sweet Grass County runs about $1,499 per acre, based on the latest county data.

What is the water situation in Sweet Grass County?

Sweet Grass County gets about 19.5" of rain a year, with severe drought in roughly 9.9% of years. On water rights, Sweet Grass County lies in the Yellowstone Compact Controlled Groundwater Area — NPS-Montana Compact CGWA covering drainages north/west of Yellowstone to protect the park's geothermal/water resources; new groundwater appropriations of any size require a DNRC permit (the 35-gpm exempt-well basis is suspended)..

How remote is Sweet Grass County?

A typical private-land location has about 2,350 people within 15 miles and 461,355 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Sweet Grass compares in Montana

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