Building permits, zoning and septic in the Town of Big Sandy, Montana

At a glance

Building permits

Dwelling code adopted; ask Town Hall to confirm the building-permit requirement and issuing office¹²

Zoning and setbacks

We could not confirm town zoning, lot-size rules or setbacks; ask Town Hall²

Public sewer

Connection required under the town’s availability rule: sewer within 500 feet of the property line, connection within 30 days after official notice³

Private wastewater

Where qualifying public sewer is unavailable, a private system must comply with the town’s wastewater rules⁵

RV and tiny-home living

We could not confirm town occupancy rules; ask Town Hall before planning either use²

Well water rights

Montana’s small-groundwater exception may apply at no more than 35 gpm and 10 acre-feet per year; a Notice of Intent is required before use⁶

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 the Town of Big Sandy, MT?

Big Sandy’s town code adopts the CABO dwelling code, including amendments and later changes made by the state Building Codes Bureau or its successor.¹ That adoption does not give us a confirmed answer about the town’s building-permit application, inspections or certificate of occupancy. Ask the Town Office which office reviews your proposed home and which building and trade permits the project requires.²

Montana’s state building-permit program excludes projects within certified local-government jurisdiction, and state exemptions apply to some residential buildings within state jurisdiction. Establish the jurisdiction before relying on an exemption for a Big Sandy project.⁷

Who should you call about Big Sandy building permits and utility connections?

Start with the Big Sandy Town Office at 406-378-2350 or [email protected]; the office address is 115 Johannes Ave Big Sandy, MT 59520.² Ask for the building-permit authority for your address, the applicable application forms and any required inspections before work starts.²

For utility-service questions, the town lists a Public Works Director contact at [email protected].⁸ Big Sandy publishes a fee-schedule link, but we could not confirm the amounts or effective date; request the current schedule and connection charges from the Town Office before budgeting.⁹²

Does the Town of Big Sandy have zoning, and can you live in an RV or tiny home?

We could not confirm Big Sandy’s zoning districts, minimum lot or dwelling size, setbacks, building height or lot coverage. Ask the Town Office for the rules that apply to the specific address and proposed use.² We also could not confirm permission for RV living, temporary camping, tiny-home occupancy, manufactured homes or an accessory dwelling inside town limits. Request an answer for the intended occupancy before buying or moving a structure onto the lot.²

Chouteau County’s development regulations govern unincorporated land, so those rules do not establish the answer inside Big Sandy. For land outside town limits, see the Chouteau County guide.¹⁰

How do sewer connections and septic permits work inside Big Sandy?

Big Sandy requires an owner to connect qualifying occupied or used property to public sewer at the owner’s expense when the sewer lies in an abutting street, alley or right-of-way and within 500 feet of the property line; connection is due within 30 days after official notice.³ Where public sewer is unavailable under that rule, the building sewer must connect to a private wastewater system that complies with the town’s private-wastewater provisions.⁵

Ask Public Works about sewer availability before designing septic.⁸ The Chouteau County Sanitarian handles county septic review, but we could not confirm the complete town-specific private-wastewater approval process; ask both the Sanitarian and Town Office about the address.⁴² Montana DEQ sanitation approval, called a COSA, does not replace a required local drainfield permit.¹¹

What are the steps to build a home in the Town of Big Sandy?

First, ask the Town Office to confirm that the parcel is inside Big Sandy and identify the building-permit authority, land-use requirements and occupancy approvals for your proposed home.² Next, discuss public water and sewer availability with Public Works, then request current utility fees from the Town Office.⁸⁹

Resolve wastewater before committing to the house layout: qualifying public sewer triggers the town’s connection requirement, while private wastewater must comply with the town’s separate provisions.³⁵ If private wastewater is proposed, consult the County Sanitarian about local review and whether Montana DEQ approval also applies.⁴ Finally, ask the Town Office to identify the building and trade applications and inspections needed for the project.²

What should you check before buying a Big Sandy lot for an off-grid home?

Big Sandy’s sewer requirement can limit an off-grid wastewater plan even when the proposed home uses independent power: determine whether the town’s public-sewer availability conditions apply to the lot.³ Do not assume a private wastewater system is allowed without meeting the town’s private-disposal provisions.⁵

For a proposed well, Montana’s groundwater permit exception may apply to uses of 35 gpm or less and no more than 10 acre-feet per year; eligibility is conditional, and a Notice of Intent must be filed with DNRC before using the water.⁶ Montana DEQ reviews divisions creating parcels smaller than 20 acres and certain parks regardless of parcel size for sanitation facilities.¹² Ask about existing sanitation approval before dividing land.¹² New or modified approaches onto a Montana state highway require an approach permit or right-of-way agreement through MDT.¹³

Watch-outs

• Big Sandy’s sewer connection rule may apply even if you intend to supply your own power or water.³
• We could not confirm town RV or tiny-home occupancy rules, building inspection requirements or owner-builder exemptions; ask the Town Office before committing to the project.²
• Montana requires floodplain approval for covered new development within a designated Special Flood Hazard Area; ask Town Hall to identify the local floodplain administrator for the Big Sandy parcel.¹⁴²

Sources

1. § 150.15 Adoption of Code (Town of Big Sandy), quoted and re-checked
2. Town of Big Sandy Town Office (townofbigsandy.com)
3. § 52.002 Public Sewer Use Required (Town of Big Sandy), quoted and re-checked
4. Chouteau County Growth Policy 2017, quoted and re-checked
5. § 52.002 Public Sewer Use Required (Town of Big Sandy), quoted and re-checked
6. Exempt Well Updates and Information (Montana statewide rule), quoted and re-checked
7. Building Permits (Montana statewide rule), quoted and re-checked
8. Town of Big Sandy Public Works (townofbigsandy.com)
9. Forms, Code & Regulations (Town of Big Sandy), quoted and re-checked
10. Chouteau County Development Regulations, quoted and re-checked
11. Engineering Infrastructure & Subdivisions — COSA FAQs, quoted and re-checked
12. Engineering Infrastructure & Subdivisions (Town of Big Sandy), quoted and re-checked
13. Approach Manual for Landowners and Developers (Montana statewide rule), quoted and re-checked
14. Stream Permitting (Montana statewide rule), 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.