Bolthole Index

Musselshell County, Montana

Building permits, zoning and land rules in Roundup, Montana

Roundup, Montana requires city building permits for fences, additions and new construction; apply at the City Office.1 Roundup has its own zoning, so the rural rules for surrounding Musselshell County are not the city’s rules.2 Additional septic installations are prohibited inside Roundup city limits, making sewer availability a central question before buying a building lot.3

At a glance

City building permits
Required for fences, additions and new construction; no city permit for a new roof1
Zoning
City zoning districts apply inside Roundup2
Septic
Additional septic installations prohibited inside city limits3
RV living
Living or sleeping in stored vehicles on residentially zoned property for more than 7 consecutive days is unlawful4
Minimum home size
700 square feet in R-1; 700 square feet of living quarters in R-256
Single-family lot size
R-1 and R-2 require 5,600 square feet and 40-foot lot width78

Who to call

Building permits

City of Roundup Building & Zoning / Compliance Office

City building permit applications, zoning and code compliance

(406)323-2804

34 3rd Ave West Roundup, MT

Septic permits

Environmental Health and Junk Vehicle Recycling Program Office

County-listed sanitation contact for questions about existing septic systems and subdivision sanitation review

535-7466

[email protected]

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 Roundup means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Roundup, MT?

Roundup requires a city building permit when building or replacing a fence, building an addition, or undertaking new construction.1 Roundup does not require a city permit for a new roof, but the City Office directs applicants to call for the complete list of building permit requirements.1 Obtain the city application at the City Office rather than treating a state exemption as permission to start work.9 Montana’s state building-permit exemptions are separate from local requirements and apply only within the state’s building-code jurisdiction.10

Who issues building permits and zoning approval in Roundup?

The City Office is Roundup’s application counter for city building permits, and the municipal Building & Zoning / Compliance Office lists its contact at 34 3rd Ave West Roundup, MT, with phone (406)323-2804.11 Ask that office for the application requirements, city building permit fee, and the inspection schedule for the proposed work.9 Roundup’s conditional-use application process can require City Council approval where zoning lists a conditional-use option.11 We could not confirm a city-specific certificate-of-occupancy requirement or owner-builder exemption; ask the City Office before relying on either.9

Does Roundup have zoning, minimum lot sizes and setbacks?

Roundup divides land into zoning districts on an official zoning map; identify the parcel’s district before choosing a house design.2 In Roundup’s R-1 Residential Single district, lots must contain at least 5,600 square feet and be at least 40 feet wide.7 Roundup’s R-2 Residential General district uses those same minimums for single-family lots, with different area provisions for multifamily development.8 Principal and accessory buildings together may occupy no more than 60% of lot area in either district.1213 Ask Roundup’s Building & Zoning Office for the setbacks applicable to the parcel and proposed building.11

How do septic permits and sewer connections work inside Roundup?

Roundup prohibits additional cesspools, septic tanks, cisterns and privy vaults inside its corporate limits.3 A county drainfield permit therefore cannot be treated as a route around Roundup’s prohibition on a new septic installation.314 Roundup requires sewer connection for residential or mercantile property abutting a city sewer where sewage collects in privy vaults, cesspools or otherwise; connections are supervised by the director of public works.15 Ask the city about sewer service for a proposed home, and use the county-listed Environmental Health office for existing-system and sanitation-review questions; that office directs callers to a contract sanitarian.1516

Can you live in an RV or tiny home on land in Roundup?

On residentially zoned property in Roundup, occupying stored campers, motor homes or recreational vehicles for living or sleeping for more than 7 consecutive days is unlawful; rear-yard storage is allowed, but front-yard storage is not.4 That limit makes an RV unsuitable as an assumed long-term home while building in Roundup.4 Roundup’s R-1 district requires at least 700 square feet per dwelling, while R-2 requires at least 700 square feet in living quarters.56 We could not confirm a separate tiny-home occupancy rule; ask the city how the proposed unit is classified.11 Montana’s municipal ADU law requires an accessory dwelling by right on a lot containing a single-family home, subject to applicable building and health requirements.17

What are the steps before building a home in Roundup?

  1. Ask Roundup’s Building & Zoning Office to identify the parcel’s zoning district and confirm the proposed use.211
  2. Resolve sewer availability with the city before planning wastewater disposal, because Roundup prohibits additional septic installations.315
  3. Obtain the city building permit application and complete list of requirements from the City Office.9
  4. Confirm any separate state building-code requirements applicable to the project before construction.10
  5. Check whether the site requires floodplain development approval with the local floodplain administrator.18

For a parcel outside city limits, use the Musselshell County guide: the state private-home building-permit exemption is conditional and does not erase Roundup’s city requirements.191

What should you check before buying land in Roundup?

For a Roundup lot, verify the zoning district, building footprint and sewer connection prospects before committing to a design.2121315 New development in a designated Special Flood Hazard Area requires consultation with the local floodplain administrator about floodplain development approval.18 If a private well is part of the plan, ask the city whether the proposed arrangement is acceptable and DNRC about water rights: Montana’s small-groundwater permit exception is conditional, and beginning in 2026 it requires a Notice of Intent before water use.1120 Musselshell County’s effective property tax rate is 0.6%; that county-level figure is context rather than a quote for a particular Roundup parcel.21

Watch-outs

  • Roundup’s building permit requirement applies to replacement fences as well as new fences.1
  • Roundup’s RV storage allowance does not allow living or sleeping in the stored vehicle for more than 7 consecutive days on residentially zoned property.4
  • Ask Roundup’s City Office about building inspections and occupancy approval before scheduling a move-in; we could not confirm the city-specific requirements.9

Sources

  1. Building and Codes - City of Roundup (Roundup), quoted and re-checked
  2. Roundup Growth Policy (Roundup), quoted and re-checked
  3. Code of Ordinances, Section 26-71 (Roundup), quoted and re-checked
  4. library.municode.com (Roundup), quoted and re-checked
  5. library.municode.com (Roundup), quoted and re-checked
  6. library.municode.com (Roundup), quoted and re-checked
  7. library.municode.com (Roundup), quoted and re-checked
  8. Code of Ordinances, Section 28-141 (Roundup), quoted and re-checked
  9. Building and Codes - City of Roundup (Roundup), quoted and re-checked
  10. Building Permits (Montana statewide rule), quoted and re-checked
  11. City of Roundup Building & Zoning / Compliance Office (roundupmontana.net)
  12. Code of Ordinances, Section 28-107 (Roundup), quoted and re-checked
  13. Code of Ordinances, Section 28-142 (Roundup), quoted and re-checked
  14. Engineering Infrastructure & Subdivisions (Montana statewide rule), quoted and re-checked
  15. Code of Ordinances, Section 26-66 (Roundup), quoted and re-checked
  16. Environmental Health and Junk Vehicle Recycling Program Office (musselshellcounty.gov)
  17. 76-2-345. Accessory dwelling units -- regulations -- restrictions, MCA (Montana statewide rule), quoted and re-checked
  18. Stream Permitting (Montana statewide rule), quoted and re-checked
  19. bsd.dli.mt.gov, quoted and re-checked
  20. Exempt Well Updates and Information (Montana statewide rule), quoted and re-checked
  21. Effective property tax rate: Bolthole Index county data

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 Roundup

Roundup’s own rules

  • Building permitRequired

    Fences, additions, and new construction inside Roundup city limits.

    • Permit must be obtained at the City Office.
    • The City does not require a permit for a new roof.
    • The city page says to call the office for the complete list of permit requirements.
    “Permits are required when building or replacing a fence, building an addition, and new construction. Please call the office for a complete list of permit requirements.”
  • Local zoningPresent

    Land inside Roundup city limits; Roundup administers its own zoning ordinance.

    • The Growth Policy states that the ordinance was last updated in 2021.
    “The city is hereby divided into zones, or districts, as shown on the official zoning map which, together with all explanatory matter thereon, is hereby adopted, referenced and declared to be a part of this chapter.”
  • Zoning districtsPublished

    The official zoning districts inside Roundup city limits.

    • The code lists R-1, R-2, HB, CBD, LI, HI, FP, and DHD.
    • The Growth Policy separately describes the Park district as P; the code section cited here lists FP and DHD.
    “For the purpose of this chapter, the city is hereby divided and classified into the following: (1) R-1 Residential Single. (2) R-2 Residential General. (3) HB Highway Business. (4) CBD Central Business District. (5) LI Light Industrial. (6) HI Heavy Industrial. (7) FP Floodplain. (8) DHD Downtown Historic District.”
  • Minimum dwelling sizeSpecified

    Dwelling units in the R-1 Residential Single district.

    • Each dwelling unit must have at least 700 square feet of floor area.

    minimum dwelling floor area: >= 700 square feet

    “Each dwelling unit shall have a minimum of 700 square feet of floor area.”
    One more reviewed finding on this topic
    • Specified — Dwelling units in the R-2 Residential General district.
      “Each dwelling unit shall have a minimum of 700 square feet of floor area in its living quarters.”
  • Minimum lot sizeSpecified

    Lots in the R-1 Residential Single district.

    • Lot width must be at least 40 feet.

    minimum lot area: >= 5600 square feet · minimum lot width: >= 40 feet

    “Lot area for any use in this district shall be no less than 5,600 square feet, and lot width shall be not less than 40 feet.”
    One more reviewed finding on this topic
    • Specified — Single-family lots in the R-2 Residential General district.
      “Minimum lot area for single-family units shall be 5,600 square feet, and a minimum lot width of 40 feet.”
  • Lot coverageSpecified

    Principal and accessory buildings in the R-1 Residential Single district.

    • Coverage includes principal and accessory buildings.

    maximum lot coverage: <= 60 percent

    “Not more than 60 percent of the lot area shall be occupied by the principal and accessory buildings.”
    One more reviewed finding on this topic
    • Specified — Principal and accessory buildings in the R-2 Residential General district.
      “Not more than 60 percent of the lot area shall be occupied by the principal and accessory buildings.”
  • Living in an RVLimited

    Living or sleeping in campers, motor homes, manufactured homes, or recreational vehicles on residentially zoned property inside Roundup city limits.

    • Such vehicles may be parked and stored in rear yards.
    • Storage is not allowed in front yards.
    • Occupancy for living or sleeping more than seven consecutive days is unlawful.
    • Recreation vehicle parks are separately limited to temporary use.

    maximum occupancy duration: <= 7 consecutive days (The cited ordinance states that more than seven consecutive days is unlawful.)

    “Campers, camping trailers, motor homes, manufactured homes (not exceeding eight feet in width and 27 feet in length), recreation vehicles, snowmobiles, and boats may be parked and stored in rear yards without fencing; however, it shall be unlawful to occupy such vehicles for living or sleeping purposes for more than seven consecutive days.”
  • Manufactured homesLimited

    Manufactured homes in the R-2 Residential General district inside Roundup city limits.

    • Class A manufactured homes are listed as permitted in R-2.
    • Class B manufactured homes are permitted only in manufactured home parks.
    • The research did not locate the full manufactured-home park standards.
    “Manufactured homes, Class A (Manufactured homes, Class B shall only be permitted in manufactured home parks).”
  • Accessory dwellingsAllowed

    Accessory apartments and efficiency units in the R-2 Residential General district inside Roundup city limits.

    “Accessory apartments and efficiency units.”
  • Septic permitLimited

    Additional onsite septic installations inside Roundup city limits.

    • The ordinance also states that a person owning, controlling, or managing property with a septic tank installed after November 19, 1974 is guilty of a misdemeanor.
    • Existing systems and external state requirements were not resolved.
    “No additional cesspools, septic tanks, cisterns, or privy vaults shall be installed in the corporate limits of the city.”
  • Off-grid sanitationProhibited

    New off-grid sewage systems using cesspools, septic tanks, cisterns, or privy vaults inside Roundup city limits.

    • The ordinance prohibits additional systems; it also requires connection for qualifying property abutting a city sewer.
    “No additional cesspools, septic tanks, cisterns, or privy vaults shall be installed in the corporate limits of the city.”
  • Mandatory utility hookupSewer (with conditions)

    Residence or mercantile real estate inside Roundup city limits that abuts a city sewer.

    • Connection is required where the property abuts a city sewer and sewage is allowed to collect in open privy vaults, cesspools, or otherwise.
    • Connections are supervised by the director of public works.
    • The ordinance does not establish a general city-water connection requirement in the cited provisions.
    “It is hereby declared to be the duty of every person owning or managing any real estate in the city abutting on any sewer in the city, to and used for residence or mercantile purposes, where sewage is allowed to collect in open privy vaults, cesspools, or otherwise, to connect the property with the city sewer.”
  • Subdividing landRegulated (with conditions)

    Subdivision activity inside Roundup city limits.

    • The city’s adopted subdivision regulations were originally developed in 2007 for use by Musselshell County.
    • The Growth Policy states that the city recently completed an update to comply with legislative changes.
    “The City’s adopted subdivision regulations were originally developed in 2007 for use by Musselshell County.”
  • Permit processPartial

    City building and zoning permits inside Roundup city limits.

    • Visit the City Office to obtain a permit.
    • The city page directs applicants to call for the complete list of requirements.
    • Conditional-use applications are submitted through the city and may require City Council approval.
    “To obtain a permit visit the City Office Permits are required when building or replacing a fence, building an addition, and new construction. Please call the office for a complete list of permit requirements.”

Rules another office applies inside Roundup

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

  • Permit feesVariable (with conditions)

    State-administered building permits for projects inside Roundup city limits when state jurisdiction applies.

    • The fee is calculated by the bureau under International Building Code Section 109.2 as modified by ARM 24.301.138.
    • A plan review fee is additional and is 35 percent of the building permit fee.
    • Certified local governments may establish their own permit fees.

    plan review fee: 35 percent of building permit fee

    “The fee for a building permit will be calculated by the bureau. Fees are calculated as established in the International Building Code Section 109.2, Schedule of Permit Fees, as modified for use by the department in ARM 24.301.138.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Roundup or Musselshell County directly.

  • Owner-builder exemption — Owner-builder exemptions inside Roundup city limits.
  • Inspections — Building inspections inside Roundup city limits.
  • Certificate of occupancy — Certificates of occupancy inside Roundup city limits.
  • Building height — Building height inside Roundup city limits.
  • Tiny homes — Tiny-home occupancy inside Roundup city limits.
4 more unanswered
  • Septic inspection
  • Well permit
  • Agricultural exemption
  • Driveway access

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

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