Building permits, zoning and land rules in Big Timber, Montana

At a glance

Building approval

Municipal land-use permit required for covered construction; ordinance exemptions apply¹

Zoning

All city land is zoned; City-County Planning administers the city ordinance²

R-S lot size

Minimum 1 acre and 125 feet wide in the R-S Rural Suburban District⁵

R-S home size

Minimum 1,000 square feet of floor area, excluding basement area, in R-S⁶

Septic

County Environmental Health is the onsite-wastewater contact; confirm city sewer requirements first³⁴

RV or tiny-home living

We could not confirm a complete city occupancy rule; ask the Zoning Officer about the proposed use²

Wells

State permit exception is conditional; qualifying users must submit a Notice of Intent before water use beginning in 2026⁷

Who to call

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

Do you need a building permit in Big Timber, MT?

Big Timber requires a municipal land-use permit for buildings or structures erected, moved, added to or structurally altered, with exemptions specified in the ordinance.¹ An internal remodeling project does not require a land-use permit, according to the city zoning office.²

The municipal land-use permit and a state building permit are separate approvals: Montana exempts certain residential construction from state building permits within state jurisdiction, while Big Timber still requires its own land-use approval for covered work.⁸¹ Ask the Zoning Officer which city exemption, if any, covers your project, and ask the Montana Building Codes Program about separate electrical, plumbing or mechanical permits.²⁹

Who handles Big Timber building and zoning applications?

The Big Timber City-County Planning Office administers and enforces the City of Big Timber Zoning Ordinance.² For a municipal land-use application, contact the Zoning Officer at (406) 932-5470 or [email protected]; completed applications are mailed or delivered to the office at 515 Hooper Street.²

The shared office is the city zoning counter as well as a county planning office, so describe the property as inside Big Timber city limits when requesting approval.² For state building-permit questions, call the Montana Building Codes Program at (406) 841-2056.¹⁰ Big Timber construction requiring a land-use permit is inspected by the Zoning Officer before an occupancy permit is issued.¹¹

Does Big Timber have zoning, minimum lot sizes and setbacks?

All land in Big Timber is zoned and subject to land-development regulations; the Planning Office administers district requirements.² Ask the Zoning Officer to identify the parcel’s district before using a dimensional standard to judge whether a home fits.²

In Big Timber’s R-S Rural Suburban District, the minimum lot area is 1 acre and minimum lot width is 125 feet.⁵ R-S dwellings require at least 1,000 square feet of floor area, excluding basement area from the minimum.⁶ The R-S standards include a 25-foot front yard and an 8-foot side yard; ask the office to check the full yard provisions against your site plan.¹²² R-S lot coverage is capped at 15%, and maximum building height is 28 feet.¹³¹⁴

How do septic permits work inside Big Timber?

Montana requires a local health-department drainfield permit even when a property already has a Certificate of Subdivision Approval.¹⁵ Sweet Grass County Environmental Health publishes septic regulations and a septic-permit application; call or text 406-366-0807 for an appointment.³

We could not confirm the complete rule for using onsite wastewater instead of municipal sewer on a Big Timber parcel; ask City Hall about sewer connection requirements and Environmental Health about onsite-system eligibility before commissioning a design.⁴³ County wastewater applications cover new systems, repairs or replacements, upgrades or expansions, and connections to existing systems.¹⁶ A city land-use permit therefore should not be treated as drainfield approval.¹¹⁵

Can you live in an RV or tiny home in Big Timber?

We could not confirm a complete Big Timber rule for residential RV occupancy, temporary camping on private land or tiny-home occupancy; ask the City-County Zoning Officer about the exact parcel and proposed living arrangement.² Include whether the dwelling has wheels, whether occupancy is temporary during construction, and how wastewater will be handled when asking for a determination.²³

A small permanent dwelling in Big Timber’s R-S district must meet the 1,000-square-foot minimum floor area, excluding basement area.⁶ That district-specific minimum does not supply an answer for an RV or for a parcel in another zoning district; have the Zoning Officer confirm the applicable district requirements before buying a unit.⁶²

What are the steps to building a home in Big Timber?

1. Start with the City-County Planning Office: confirm the parcel’s zoning district and which municipal land-use approval covers the proposed home.²¹
2. Next, ask City Hall about water and sewer connections and Environmental Health about any proposed onsite wastewater system.⁴³
3. Have the Floodplain Administrator check the location; new development in a designated Special Flood Hazard Area requires floodplain approval.¹⁷¹⁸
4. Submit the city land-use application to Planning and settle any separate state trade-permit requirements before starting the relevant work.²⁹
5. Arrange the Zoning Officer’s construction inspection and occupancy permit before occupancy.¹¹

If proposing a well, Montana’s exception is limited to 35 gallons per minute and 10 acre-feet per year, with a Notice of Intent required before water use beginning in 2026.⁷ For land outside city limits, use the Sweet Grass County guide to distinguish rural building requirements from Big Timber’s municipal land-use approval.¹⁹¹

Watch-outs

• Big Timber’s municipal land-use permit is still required for covered construction even when a Montana state building-permit exemption applies.¹⁸
• We could not confirm a Big Timber owner-builder exemption from municipal land-use approval; ask the Zoning Officer before relying on an exemption.²
• Confirm municipal sewer requirements with City Hall before assuming that a Big Timber lot can use septic or off-grid sanitation.⁴³

Sources

1. Big Timber Zoning Ordinance, Chapter 23 (Big Timber), quoted and re-checked
2. Big Timber City-County Planning Office (sgcountymt.gov)
3. Sweet Grass County Environmental Health Department (sgcountymt.gov)
4. Big Timber City Hall (cityofbigtimber.com)
5. City of Big Timber Zoning Ordinance (Big Timber), quoted and re-checked
6. City of Big Timber Zoning Ordinance (Big Timber), quoted and re-checked
7. Groundwater permit exceptions (Big Timber), quoted and re-checked
8. Building Permits (Montana statewide rule), quoted and re-checked
9. Building Permits (Montana statewide rule), quoted and re-checked
10. Montana Building Codes Program (bsd.dli.mt.gov)
11. Big Timber Zoning Ordinance, occupancy permit (Big Timber), quoted and re-checked
12. City of Big Timber Zoning Ordinance (Big Timber), quoted and re-checked
13. City of Big Timber Zoning Ordinance (Big Timber), quoted and re-checked
14. City of Big Timber Zoning Ordinance (Big Timber), quoted and re-checked
15. Engineering Infrastructure & Subdivisions (Montana statewide rule), quoted and re-checked
16. Onsite Wastewater Treatment System Permit Application, quoted and re-checked
17. City-County Planning Office — Floodplain Administrator (sgcountymt.gov)
18. Stream Permitting (Montana statewide rule), quoted and re-checked
19. bsd.dli.mt.gov, 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.