Bolthole Index

Stillwater County, Montana

Building permits, zoning and land rules in Town of Columbus, Montana

Town of Columbus, Montana directs building and zoning questions to Public Works before a project starts; we could not confirm a general town building-permit requirement.1 Columbus has its own zoning, and septic systems are prohibited inside town limits.23 RV living or sleeping cannot exceed 30 consecutive days.4 For a home in Stillwater County’s town of Columbus, confirm the zoning district and sewer-service arrangements with Public Works before buying.231

At a glance

Building permits
General town requirement unconfirmed; ask Public Works before starting1
Zoning
Town zoning applies; use the official zoning map2
Septic systems
Prohibited inside town limits3
RV living
Living or sleeping occupancy cannot exceed 30 consecutive days4
Minimum home size
R-2: 700 square feet; AO: 1,000 square feet per dwelling56
Wells
Advance approval and well permit from the director of public works7
Manufactured homes
Use permit or conditional use permit before installation, except in an approved and licensed park8

Who to call

Zoning

Columbus Public Works

Town building and zoning questions, public works and roads; well and water-service application forms

406-322-5313 ext. 300

[email protected]

1258 1st Ave South Columbus, MT 59019

Septic permits

Stillwater County Environmental Health Department

County onsite wastewater questions and historical septic records; town septic prohibition still applies

406-322-8055

431 Quarry Road

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

Off-grid gear

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

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Do you need a building permit in Town of Columbus, MT?

Columbus Public Works asks owners to contact the department about building and zoning inside town limits before starting a project.1 We could not confirm Columbus’s general building-permit requirement, building-inspection procedure or certificate-of-occupancy rule; ask Public Works which approvals apply to your proposed home.1

Columbus zoning permits have a separate timing rule: a permit expires if work has not commenced within 120 days, or if work is suspended or abandoned for 120 days, subject to the section’s stated exceptions.9 Ask Public Works to identify the required zoning approval and construction approvals separately before scheduling work.19

Who handles building and zoning questions in Town of Columbus?

Columbus Public Works is the town’s starting point for building and zoning questions, and the department also answers questions about roads inside town limits.1 Contact Columbus Public Works at 406-322-5313 ext. 300 or [email protected].1

The town’s Public Works page provides principal-use, accessory-use, conditional-use, excavation, well and water-service permit forms.1 Ask Public Works which forms fit the site and proposed use; the availability of these specific forms does not resolve the unconfirmed general building-permit requirement.1 A manufactured home intended as a residence needs a zoning-officer use permit or conditional use permit before installation, except within a previously approved and licensed manufactured-home park.8

Does Town of Columbus have zoning, lot-size rules and setbacks?

Columbus has its own zoning districts, with boundaries shown on the official zoning map.2 Match the parcel to its district before choosing a house footprint: Columbus’s dimensional standards differ by district.56

In Columbus’s R-2 district, each single-family dwelling needs at least 700 square feet of floor area, and principal plus accessory buildings may occupy no more than 40% of the lot.510 R-2 minimum yards are 20 feet in front, 20 feet behind a principal structure, 10 feet behind an accessory use and 8 feet on each side.11

In Columbus’s AO district, each dwelling needs at least 1,000 square feet; building coverage is capped at 10%, with yards of 35 feet in front and 25 feet at the rear and on each side.61213 In RE, soil and groundwater conditions determine lot area, but the lot cannot be smaller than 1 acre or narrower than 150 feet.14

How do septic and well approvals work inside Town of Columbus?

Columbus prohibits septic systems within town limits, so a county septic application is not a substitute for resolving the town’s sewer-service requirements.3 Public Works provides a water-service permit form; ask the department to confirm water and sewer availability and connection requirements for the address.1 We could not confirm a mandatory utility-connection standard for every new home in Columbus.1

Stillwater County Environmental Health handles onsite wastewater matters and can help locate historical septic records, which are generally filed under the original owner’s name.15 Columbus’s prohibition still governs a proposed septic system inside town limits.3

Installing a well in Columbus requires advance approval and a permit from the director of public works, followed by notice of completion.7 Separately, Montana groundwater use at no more than 35 gallons per minute and 10 acre-feet annually may qualify for a state water-permit exception; beginning in 2026, a Notice of Intent must be filed with DNRC before using water through that exception.16

Can you live in an RV or tiny home in Town of Columbus?

Columbus makes living or sleeping in campers, camping trailers, motor homes and recreational vehicles unlawful for more than 30 consecutive days.4 A plan to stay in an RV throughout a longer home build therefore needs a different accommodation arrangement; owning the lot does not remove the occupancy limit.4 Columbus’s separate travel-trailer-park and campground rule permits recreational shelter arrangements only on a temporary basis.17

We could not confirm a tiny-home-specific occupancy rule for Columbus; ask Public Works how the proposed structure and use would be classified.1 A small permanent house must account for district minimum floor area: R-2 requires 700 square feet per single-family dwelling, while AO requires 1,000 square feet per dwelling.56 Montana municipal zoning law also requires an accessory dwelling unit by right on a lot containing a single-family dwelling, subject to applicable codes and health and safety rules; ask Public Works how Columbus implements that requirement.18

What steps should you take before building in Town of Columbus?

Start with the parcel’s location and zoning district: Columbus’s official zoning map includes the town and its extraterritorial area.2 For land outside the town’s zoning jurisdiction, consult the Stillwater County guide; the county development regulations apply to unincorporated land but exclude Columbus’s extraterritorial zoning jurisdiction.19

Next, take the proposed use and site layout to Columbus Public Works and ask which zoning, excavation, water-service and construction approvals are needed.1 Resolve sewer service before relying on a septic design, because Columbus prohibits septic systems inside town limits.3 Obtain the director of public works’ advance approval and well permit if installing a well, and address DNRC water-right requirements separately.716 Finally, plan the construction schedule around the zoning permit’s 120-day commencement and suspension limits, with Public Works confirming any applicable exception.91

Watch-outs

  • Stillwater County’s residential setback answer does not apply inside Columbus’s town zoning districts; Columbus R-2 and AO have their own yard requirements.111320
  • Columbus’s outside-storage provision also names manufactured homes in its 30-consecutive-day living or sleeping restriction; ask Public Works how that provision interacts with an approved permanent manufactured-home residence.481
  • We could not confirm Columbus’s general building-permit requirement or inspection process; obtain a project-specific answer from Public Works before construction.1

Sources

  1. Columbus Public Works (townofcolumbus.com)
  2. Columbus Code § 17.12.030—Boundaries of districts and zoning map (Town of Columbus), quoted and re-checked
  3. Columbus Code § 13.08.100—Septic systems not allowed (Town of Columbus), quoted and re-checked
  4. Columbus Code § 17.96.090—Outside storage requirements (Town of Columbus), quoted and re-checked
  5. Columbus Code § 17.28.040—R-2 lot coverage and floor area (Town of Columbus), quoted and re-checked
  6. Columbus Code § 17.20.040—AO lot coverage and floor area (Town of Columbus), quoted and re-checked
  7. Columbus Code § 15.08.030—Permit required for installation (Town of Columbus), quoted and re-checked
  8. Columbus Code § 17.108.020—Permits (Town of Columbus), quoted and re-checked
  9. Columbus Code § 17.116.040—Expiration of permits (Town of Columbus), quoted and re-checked
  10. Columbus Code § 17.28.040—R-2 lot coverage and floor area (Town of Columbus), quoted and re-checked
  11. Columbus Code § 17.28.050—R-2 yards (Town of Columbus), quoted and re-checked
  12. Columbus Code § 17.20.040—AO lot coverage and floor area (Town of Columbus), quoted and re-checked
  13. Columbus Code § 17.20.050—AO yards (Town of Columbus), quoted and re-checked
  14. Columbus Code § 17.36.030—RE lot area and width (Town of Columbus), quoted and re-checked
  15. Stillwater County Environmental Health Department (stillwatercountymt.gov)
  16. Exempt Well Updates and Information (Montana statewide rule), quoted and re-checked
  17. Columbus Code § 17.112.020—Permitted uses (Town of Columbus), quoted and re-checked
  18. 76-2-345. Accessory dwelling units -- regulations -- restrictions, MCA (Montana statewide rule), quoted and re-checked
  19. Stillwater County Development Regulations, quoted and re-checked
  20. Planning | Stillwater County, MT, quoted and re-checked

Written October 11, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Town of Columbus

Town of Columbus’s own rules

  • Local zoningPresent (with conditions)

    Land inside Columbus town limits.

    • District locations and boundaries are established through the official zoning map.
    “The location and boundaries of districts established in the city and its extraterritorial area are shown on the official zoning map of the city.”
  • Living in an RVLimited

    Living or sleeping occupancy of RVs, campers, camping trailers, motor homes, and manufactured homes inside Columbus town limits.

    • Occupancy for living or sleeping purposes may not exceed 30 consecutive days.

    maximum consecutive occupancy: <= 30 days

    “Campers, camping trailers, motor homes, recreational vehicles, snowmobiles and boats may be parked and stored in rear, side or front yards; however, it is unlawful to occupy any such campers, camping trailers, motor homes, manufactured homes or recreational vehicles, for living or sleeping purposes for more than thirty (30) consecutive days.”
  • Camping on your landLimited

    Camping in travel trailer parks and campgrounds inside Columbus town limits.

    • The temporary-use rule applies to travel trailer parks and campgrounds.
    “Travel trailer parks and campgrounds may be used for recreational vehicles, travel trailers, equivalent facilities in or on automotive vehicles, tents or other short term recreational shelter arrangements on a temporary basis only.”
  • Manufactured homesLimited

    Manufactured homes used as residences inside Columbus town limits.

    • Owner or installer must obtain a city zoning-officer use permit or conditional use permit before installation on a lot, except in a previously approved and licensed manufactured-home park.
    “The owner or the installer of a manufactured home to be used as a residence must obtain a use permit or conditional use permit from the city of Columbus zoning officer before the manufactured home is installed on any lot, except within previously approved and licensed manufactured home (mobile home) park.”
  • Septic permitLimited

    New septic systems inside Columbus city limits.

    • Septic systems are prohibited within city limits.
    “Septic systems shall not be allowed within the city limits.”
  • Off-grid sanitationLimited

    Off-grid septic sanitation inside Columbus city limits.

    • This determination concerns septic systems; the code directly prohibits them within city limits.
    “Septic systems shall not be allowed within the city limits.”
  • Well permitRequired

    Installation of water wells inside Columbus town limits.

    • Approval and permit must be obtained in advance from the director of public works; notice of completion is required.
    “All persons who desire to install a water well after the effective date of this chapter shall obtain approval of their proposed installation and a permit therefore in advance from the director of public works and shall give notice of completion of the installation.”
  • Permit processPartial

    Zoning permits issued by the Columbus zoning officer.

    • Permit expires if work has not commenced within 120 days, or is suspended or abandoned for 120 days; recommencement requires a new permit subject to stated exceptions in the section.

    commencement or suspension period: 120 days

    “Every permit issued by the zoning officer under the provisions of this title shall expire by limitation and become null and void. If the building or work authorized by such permit has not commenced within one hundred twenty (120) days from the date of such permit, or if the building or work authorized by such permit is suspended or abandoned at any time after the work is commenced for a period of one hundred twenty (120) days, the permit shall expire.”

Rules another office applies inside Town of Columbus

Town of Columbus does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum dwelling sizeSpecified

    AO Agricultural/Open Space Zone inside Columbus town limits.

    • Applies to each dwelling unit in the AO district.

    minimum floor area: >= 1000 square feet

    “No more than ten percent of the lot area shall be covered by the principal and accessory buildings. Each dwelling unit shall have a minimum floor area of one thousand (1,000) square feet.”
    One more reviewed finding on this topic
    • Specified — R-2 Residential, Single-Family District (5,500 square feet) inside Columbus town limits.
      “Not more than forty (40) percent of the lot area shall be occupied by the principal and accessory buildings. Each single-family dwelling shall have a minimum of seven hundred (700) square feet of floor area.”
  • Minimum lot sizeSpecified

    RE Residential Estates District inside Columbus town limits.

    • Lot area is determined by soil, groundwater, and other urban-development limitations; it may not be less than one acre.

    minimum lot area: >= 1 acre · minimum lot width: >= 150 feet

    “Lot area for this district shall be determined by existing soil conditions, groundwater conditions and other limitations for urban development. Under no circumstances shall the lot area be less than one acre with a lot width not less than one hundred fifty (150) feet.”
  • SetbacksSpecified

    R-2 Residential, Single-Family District (5,500 square feet) inside Columbus town limits.

    • Accessory-use rear-yard setback differs from a principal structure.

    front yard: >= 20 feet · rear yard principal structure: >= 20 feet · rear yard accessory use: >= 10 feet · side yard each side: >= 8 feet

    “Every lot shall have the following minimum yards. Front yard 20 feet Rear yard, principal structure 20 feet Rear yard, accessory use 10 feet Side yard 8 feet each side”
    One more reviewed finding on this topic
    • Specified — AO Agricultural/Open Space Zone inside Columbus town limits.
      “Every lot shall have the following minimum yards: Front yard 35 feet Rear yard 25 feet Side yard 25 feet each side”
  • Lot coverageSpecified

    AO Agricultural/Open Space Zone inside Columbus town limits.

    • Limit includes principal and accessory buildings.

    maximum lot coverage: <= 10 percent

    “No more than ten percent of the lot area shall be covered by the principal and accessory buildings. Each dwelling unit shall have a minimum floor area of one thousand (1,000) square feet.”
    One more reviewed finding on this topic
    • Specified — R-2 Residential, Single-Family District (5,500 square feet) inside Columbus town limits.
      “Not more than forty (40) percent of the lot area shall be occupied by the principal and accessory buildings. Each single-family dwelling shall have a minimum of seven hundred (700) square feet of floor area.”

Still unanswered

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

  • Building permit — General building construction inside Columbus town limits.
  • Owner-builder exemption — Owner-built construction inside Columbus town limits.
  • Building code adopted — Building construction inside Columbus town limits.
  • Inspections — Building construction inside Columbus town limits.
  • Certificate of occupancy — Buildings inside Columbus town limits.
8 more unanswered
  • Building height
  • Tiny homes
  • Accessory dwellings
  • Septic inspection
  • Mandatory utility hookup
  • Agricultural exemption
  • Subdividing land
  • Short-term rentals

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 Columbus publishes no rule on the point, not that none exists. Stillwater County’s page lists the county offices to call.

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