Bolthole Index

Gallatin County, Montana

Building permits, zoning and septic in the Town of West Yellowstone, Montana

The Town of West Yellowstone, Montana requires building permits for new buildings, moving structures, additions and structural alterations, and valid permits for land-use changes.1 West Yellowstone sets its own zoning; ask the town clerk for the parcel’s current district.2 In Gallatin County, local wastewater-system permits come through the Gallatin City-County Health Department; confirm sewer service with the town before planning private septic.34

At a glance

Building permits
Required for covered construction and land-use changes inside town limits1
Zoning
Town zoning districts; current map maintained by the town clerk2
Septic
County health department handles local wastewater permitting; ask town about sewer service34
Lot size
R-2: 5,000 square feet and 60 feet wide, with public open-space exceptions5
Accessory dwellings
Allowed on a single-unit dwelling lot, subject to size, district and utility requirements6
Public water
Connection generally required before occupancy; optional beyond 300 feet from a main, with existing-lot exceptions7

Who to call

Building permits

Town of West Yellowstone Public Services — Building Inspector and Code Enforcement

Town building and zoning application questions and building inspections

+1 406 646 7795

[email protected]

440 Yellowstone Avenue

Also useful

Town of West Yellowstone Public Services — Water and Wastewater

Municipal water and sewer service, utility taps, and excavation permits in the town public right of way

+ (406) 646 7609

[email protected]

440 Yellowstone Avenue

Septic permits

Gallatin City-County Health Department (Environmental Health)

Wastewater-system permits, registration, plan review, and inspections in Gallatin County

406.582.3120

[email protected]

400 E. Babcock Street Bozeman, MT 59715

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 Town of West Yellowstone means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in the Town of West Yellowstone, MT?

Inside West Yellowstone town limits, a building or other structure cannot be erected, moved, added to or structurally altered without valid permits; changing land use also requires valid permits.1 West Yellowstone adopts the current Montana Department of Labor and Industry building, mechanical, plumbing, electrical and related codes by reference through administrative action.8 The town’s building-code enforcement includes residential buildings, farm or ranch buildings and private owner-use garages or storage structures.8 Ask the town building office which applications your project needs before construction begins.9

Who is the Town of West Yellowstone building department?

The Town of West Yellowstone Public Services Department lists a Building Inspector and Code Enforcement role and provides building and zoning application forms on its Public Services page.9 Contact the building office through the listed email or call the town offices at +1 406 646 7795 for application questions.9 Building inspections are conducted by the building official or other qualified, authorized personnel, with other departmental inspections coordinated by the building official.10 West Yellowstone’s town council sets the fee schedule by resolution and posts it in town offices; fees must be paid before the building permit or related approval is issued.11

Does the Town of West Yellowstone have zoning, lot sizes and setbacks?

West Yellowstone has town zoning districts, and the official zoning map maintained by the town clerk is the final authority for current zoning status.2 In the town’s R-2 residential single-unit medium-density district, lots generally need at least 5,000 square feet and 60 feet of width; public parks, playgrounds and open-space lots have an exception.5 R-2 minimum yards are 20 feet in front, 20 feet in back and 8 feet on each side, with additional corner-lot and accessory-building rules.12 Buildings may occupy no more than 45% of an R-2 lot.13 Short-term rentals are prohibited in R-2, so do not buy an R-2 house assuming vacation-rental income is available.14

How do septic permits work inside the Town of West Yellowstone?

Gallatin City-County Health Department administers local wastewater-system permitting in Gallatin County, and a local wastewater treatment system permit is required before installation.315 Site evaluations must be performed by a county-registered site evaluator or Montana-registered professional engineer, and a county-registered installer must be on site during installation.16 For a West Yellowstone parcel, ask town Public Services about municipal sewer availability and connection requirements before commissioning a private-system design; direct private wastewater-system questions to Environmental Health.417 West Yellowstone accessory dwelling applications specifically require municipal water and sewer will-serve letters.6

Can you live in an RV or tiny home in the Town of West Yellowstone?

We could not confirm a complete rule for living in an RV on private land, tiny-home occupancy or a minimum dwelling floor area inside West Yellowstone; ask the town building office about your proposed use and parcel before buying.9 West Yellowstone does allow an accessory dwelling unit by right on a lot containing a single-unit dwelling, subject to district standards and application requirements.6 Attached or detached accessory units are limited to 75% of the principal dwelling’s gross floor area or 1,000 square feet, whichever is less.6 In residential districts, accessory dwelling units cannot be short-term rentals or timeshares.6

Building a home in the Town of West Yellowstone: what are the steps?

  1. Ask the town clerk to confirm the parcel’s current zoning district, then design around the district’s use and dimensional requirements.2
  2. Confirm water and sewer service with town Public Services; West Yellowstone generally requires public-water connection before dwelling occupancy, subject to distance and existing-lot exceptions.47
  3. Submit the town building and applicable land-use applications and pay required fees before starting covered work.111
  4. Arrange town building inspections and obtain an excavation permit before utility taps or driveway construction in the town public right of way.104

What should you check before buying in the Town of West Yellowstone?

For a West Yellowstone building site, confirm physical and legal access: new or moved buildings need a lot adjacent to a public street or access to an approved private street, alley, parkway or interior park, with safe servicing and fire access.18 Ask Public Services about utility taps and public-way work, because the excavation permit requires written proof of insurance and bonding.4 Public-water connection is optional when the parcel is not within 300 feet of a water main; connection costs otherwise fall on the owner, and existing improved lots have a specific exception.7 For land outside town limits, use the Gallatin County guide for the county’s zoning and land-use approval requirements.19

Watch-outs

  • Starting a covered West Yellowstone project before applying for the necessary building or land-use permit triggers double the application fee.11
  • We could not confirm an owner-builder permit exemption inside West Yellowstone; ask the town building office before relying on an exemption.9
  • West Yellowstone’s accessory dwelling approval requires municipal water and sewer will-serve letters, so resolve utility service before committing to an accessory unit.6

Sources

  1. Chapter 17.08 Administrative Regulations and Processes (Town of West Yellowstone), quoted and re-checked
  2. Chapter 17.06 Establishment of Districts (Town of West Yellowstone), quoted and re-checked
  3. Wastewater (Septic) Treatment - Healthy Gallatin, quoted and re-checked
  4. Town of West Yellowstone Public Services — Water and Wastewater (westyellowstone.gov)
  5. Chapter 17.12 R-2 Residential – Single-Unit – Medium Density (Town of West Yellowstone), quoted and re-checked
  6. Chapter 17.30 Accessory Dwelling Unit Structures (Town of West Yellowstone), quoted and re-checked
  7. Article I: General Provisions – Fees (Town of West Yellowstone), quoted and re-checked
  8. Title 15 Buildings and Construction (Town of West Yellowstone), quoted and re-checked
  9. Town of West Yellowstone Public Services — Building Inspector and Code Enforcement (westyellowstone.gov)
  10. Title 15 Buildings and Construction (Town of West Yellowstone), quoted and re-checked
  11. ecode360.com (Town of West Yellowstone), quoted and re-checked
  12. Chapter 17.12 R-2 Residential – Single-Unit – Medium Density (Town of West Yellowstone), quoted and re-checked
  13. Chapter 17.12 R-2 Residential – Single-Unit – Medium Density (Town of West Yellowstone), quoted and re-checked
  14. Chapter 17.12 R-2 Residential – Single-Unit – Medium Density (Town of West Yellowstone), quoted and re-checked
  15. Wastewater (Septic) Treatment - Healthy Gallatin, quoted and re-checked
  16. Septic (Wastewater Treatment), quoted and re-checked
  17. Gallatin City-County Health Department (Environmental Health) (healthygallatin.org)
  18. Chapter 17.08 Administrative Regulations and Processes (Town of West Yellowstone), quoted and re-checked
  19. Zoning Regulations, quoted and re-checked

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.

Answers from the rulebook for Town of West Yellowstone

Town of West Yellowstone’s own rules

  • Building permitRequired

    Erection, movement, addition, structural alteration, or land-use change inside West Yellowstone town limits.

    • A valid permit is required before the covered work or land-use change.
    • Building permits must comply with applicable building codes.
    • The application may require information about the building, land, occupants, housing or rental units, and lot conditions.
    “No building or other structure shall be erected, moved, added to, or structurally altered and no land use shall be changed without valid permits as described in this chapter.”
  • Building code adoptedAdopted

    Buildings within the town building-code enforcement area.

    • Current Montana Department of Labor and Industry building, mechanical, plumbing, electrical and related codes are adopted by reference through administrative action.
    • The codes apply to buildings within the town building-code enforcement area, including residential buildings containing fewer than five dwelling units, farm or ranch buildings, and private garages or storage structures used only by the owner.
    “The current editions of the building, mechanical and related codes and all accompanying appendices, amendments and modifications adopted by the Bureau of Building and Measurement Standards, Montana Department of Labor and Industry (or its successor), as set out in the Administrative Rules of Montana, as amended from time to time by the Department of Labor and Industry, shall be adopted by reference through administrative action of the operations manager, as authorized by Section 50-60-301(1)(b), MCA, excluding any exceptions noted in Title 50, Chapter 60 or any regulations not applicable to local government jurisdictions.”
  • InspectionsRequired

    Building construction inside West Yellowstone town limits.

    • Inspections are conducted by the building official or other qualified and authorized personnel.
    • Other departmental inspections must be coordinated by the building official.
    • Fire-code inspections may be assigned to the building official or a designated fire inspector.
    “Inspections shall be conducted by the building official or other appropriately qualified and authorized personnel.”
  • Zoning districtsPublished

    Land inside West Yellowstone town limits.

    • The official zoning map is maintained by the town clerk and is the final authority for current zoning status.
    • The code lists residential, business, manufacturing, entertainment, public-land, downtown-overlay, and transitional districts.
    “The town is divided into zones, or districts, as shown on the official zoning maps which, together with all explanatory matter thereon, are adopted by reference and declared to be a part of this chapter.”
  • Minimum lot sizeSpecified

    R-2 residential single-unit medium-density district inside West Yellowstone town limits.

    • The exception is for a public park, playground, or open-space lot, for which no minimum lot size requirement applies.

    minimum lot area: >= 5000 square feet (Public park, playground, or open space.) · minimum lot width: >= 60 feet (Public park, playground, or open space.)

    “Lot area for any use in this district shall be not less than five thousand square feet and no lot width shall be less than sixty feet, unless the lot is to be used for a public park, playground, or open space where there is no minimum lot size requirement.”
  • SetbacksSpecified

    R-2 residential single-unit medium-density district inside West Yellowstone town limits.

    • Accessory buildings generally may not be placed in required yards.
    • A residential garage may be placed within 10 feet of the rear property line if it conforms to the applicable definition.
    • An accessory building may not be within 10 feet of the principal building unless the town grants a variance.
    • Corner lots have additional front-yard rules.

    front yard: >= 20 feet · rear yard: >= 20 feet · each side yard: >= 8 feet

    “Every lot in the R-2 district shall have the following minimum yards: Front yard, twenty feet. Rear yard, twenty feet. Side yards, eight feet each side.”
  • Lot coverageSpecified

    R-2 residential single-unit medium-density district inside West Yellowstone town limits.

    • The limit applies to buildings occupying the lot.

    maximum building lot coverage: <= 45 percent

    “No more than forty-five percent of the lot area shall be occupied by buildings.”
  • Accessory dwellingsAllowed (with conditions)

    Accessory dwelling units on lots containing a single-unit dwelling inside West Yellowstone town limits.

    • At least one accessory dwelling unit is allowed by right.
    • An attached, detached, or internal unit may not exceed 75% of the principal dwelling's gross floor area or 1,000 square feet, whichever is less, when attached or detached.
    • In residential districts, an accessory dwelling unit may not be used as a short-term rental or timeshare.
    • A municipal water-system will-serve letter and municipal sewer-system will-serve letter are required.
    • Applicable fees, building plans, elevations, and scaled site plans are required.
    • Dimensional requirements follow the district where the unit is placed.

    maximum detached or attached ADU size: 75% of principal dwelling gross floor area or 1,000 square feet, whichever is less

    “A minimum of one accessory dwelling unit is allowed by right on a lot or parcel that contains a single-unit dwelling per the definition in this chapter.”
  • Mandatory utility hookupWater (with conditions)

    Improved parcels and premises inside West Yellowstone town limits.

    • Connection to the public water system is required before occupation for a dwelling or commercial building.
    • If the parcel is not within 300 feet of a water main, connection is optional.
    • The owner bears connection costs and must obtain a water-system permit.
    • The ordinance does not require mandatory connection of improved lots existing when the ordinance was adopted unless a subscription agreement was signed and filed with the town clerk.

    maximum distance for optional water connection: <= 300 feet (If a parcel is not within 300 feet of a water main, connection is optional.)

    “Every parcel of land or premises within the boundaries of the town that is to be improved by any person or persons shall be connected to the public water system. The owner or person in charge of such land shall make or cause to be made such connection before such land is occupied for a dwelling or commercial building.”
  • Driveway accessRequired

    Every building erected or moved inside West Yellowstone town limits.

    • The lot must be adjacent to a public street or have physical and legal access to an approved private street, alley, parkway, or interior park.
    • Access must provide safe and convenient servicing, fire protection, required parking, and loading.
    • The town will not maintain private-property access or access from private streets, alleys, parkways, or interior parks.
    “Every building hereafter erected or moved shall be on a lot adjacent to a public street, or with physical and legal access to an approved private street, alley, parkway, or interior park, and all structures shall be so located on lots as to provide safe, convenient access for servicing, fire protection, required off-street parking per Chapter 17.37, and off-street loading per Chapter 17.38.”
  • Short-term rentalsProhibited

    Short-term rentals in the R-2 residential single-unit medium-density district.

    • This claim is limited to the R-2 district; the research did not establish the rule for every other district.
    “The following uses are prohibited in the R-2 district: Heavy manufacturing. Industrial uses. Outdoor merchandise. Short-term rentals. Salvage yards. Timeshares.”
  • Permit feesPublished (with conditions)

    Building, land-use, zoning, subdivision, appeal, conditional-use, and variance permits inside West Yellowstone town limits.

    • The town council sets fees by resolution.
    • The schedule is posted in town offices.
    • Fees must be paid before the permit or related action is issued.
    • A permit application made after use or construction begins requires double the application fee.
    “The town council shall establish a schedule of fees, charges, and expenses and a collection procedure for building permits, land use and zoning permits, subdivisions, appeals, and other matters pertaining to this title. The schedule of fees shall be set by resolution of the town council and shall be posted in the town offices.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Town of West Yellowstone or Gallatin County directly.

  • Owner-builder exemption — Owner-builders inside West Yellowstone town limits.
  • Minimum dwelling size — Residential dwellings inside West Yellowstone town limits.
  • Building height — Buildings inside West Yellowstone town limits.
  • Living in an RV — RV occupancy on private land inside West Yellowstone town limits.
  • Camping on your land — Temporary camping inside West Yellowstone town limits.
10 more unanswered
  • Tiny homes
  • Manufactured homes
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Agricultural exemption
  • Subdividing land
  • Building in a floodplain

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.

Unanswered questions are usually a sign that Town of West Yellowstone publishes no rule on the point, not that none exists. Gallatin County’s page lists the county offices to call.

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