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Plumbing Permit in Unincorporated Yellowstone County, Montana

Plumbing work in unincorporated Yellowstone County is permitted directly by the Montana Building Codes Bureau under Title 50, Chapter 60, Section 505, MCA and ARM 24.301.301/24.301.361, since the county is not a certified local plumbing-code jurisdiction. A per-fixture fee schedule applies. Homeowners performing their own plumbing on their own owner-occupied, non-rental residence are exempt from needing a permit.

Verified 2026-07-02 · Source

When you need this permit

  • Any installation, removal, alteration, or repair of plumbing/drainage systems by a business, trade, or contractor requires a state plumbing permit
  • Exemption: homeowners doing their own plumbing installation on a residence for their own personal use (not built on speculation of resale and not intended as a rental) do not need a permit
  • Farms, ranches, mines, mills, smelters, railroads, and public utilities are exempt from state plumbing permit requirements
  • 2021 Uniform Plumbing Code fixture table (ARM 24.301.351) governs minimum required fixtures

Required documents

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Fee schedule

Each plumbing fixture or trapMontana Building Codes Bureau, Application for Plumbing Permit (ARM 24.301.301/24.301.361, Rev. 11/25) — covers bath tub, lavatory, shower, water closet, kitchen sink, dishwasher, etc.
$10 per fixture
Each new water heater or replacementSame source, verbatim fee line item
$25
Each connection of building water supply to water service/public utility or private wellSame source
$20
Each connection of building drain to sewer system/public or septicSame source
$20
Gray water system (commercial or residential)Same source
$60
Repair or alteration of drainage or vent pipingSame source
$30
Alteration or repair of water piping and/or treatmentSame source
$30
Each storm drain and storm drainageSame source
$30
Each lawn sprinkler, fire protection system, meter, or backflow deviceSame source
$30
Each hose bibb, vacuum breaker, and/or backflow deviceSame source
$6
Each industrial water pre-treatment equipment (incl. drainage/vent)Same source
$30
Medical gas piping systems (per type)Same source; additional $10 per outlet over 20 total outlets
$100

Review timeline

Plan reviewTypical estimate — confirm current times with the Unincorporated Yellowstone County building department
~1–5 business days

How long did your Plumbing Permit permit actually take in Unincorporated Yellowstone County?

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Inspection process

    See the full Unincorporated Yellowstone County inspection guide — scheduling & re-inspection fees →

    Tips

    • Homeowners performing their own plumbing work on their own owner-occupied residence (not a rental, not built for resale) do not need a state plumbing permit at all — but hired plumbers must always hold a Montana Master Plumber license and pull the permit. Owner-builder
    • The fee is calculated per fixture/trap installed, not a flat project fee — a full new-construction bathroom (tub, lavatory, water closet) plus a kitchen sink and water heater would be billed line by line at $10 per fixture plus the specific line items (e.g., $25 for the water heater).
    • Montana adopted the 2021 Uniform Plumbing Code effective June 11, 2022; the minimum fixture table is at ARM 24.301.351.
    • Applications must include the 17-digit geocode, parcel number, and legal description (section/township/range) for the property.

    Frequently asked questions

    Yes, if a licensed plumber performs the work — the fee is $25 per the Montana Building Codes Bureau plumbing permit fee schedule. If you personally own and occupy the residence (not a rental, not built for resale) and are doing the work yourself, no state plumbing permit is required.

    In Unincorporated Yellowstone County, the published Each plumbing fixture or trap is: $10 per fixture. Additional published fees: Each new water heater or replacement — $25; Each connection of building water supply to water service/public utility or private well — $20; Each connection of building drain to sewer system/public or septic — $20; Gray water system (commercial or residential) — $60; Repair or alteration of drainage or vent piping — $30; Alteration or repair of water piping and/or treatment — $30; Each storm drain and storm drainage — $30; Each lawn sprinkler, fire protection system, meter, or backflow device — $30; Each hose bibb, vacuum breaker, and/or backflow device — $6; Each industrial water pre-treatment equipment (incl. drainage/vent) — $30; Medical gas piping systems (per type) — $100. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

    Plan review for a plumbing permit in Unincorporated Yellowstone County typically runs 1–5 business days. This is an estimate, not a published figure — confirm current review times with Montana Department of Labor & Industry — Building Codes Bureau (Business Standards Division, Building and Commercial Measurements Bureau) at (406) 841-2056.

    You'll need: Application for Plumbing Permit (BCP-1). See the required-documents checklist on this page for details on each.

    Apply through Montana Department of Labor & Industry — Building Codes Bureau (Business Standards Division, Building and Commercial Measurements Bureau) at 301 South Park Ave, Floors 4-5, Helena, MT 59620 (mailing: Building Codes Bureau, PO Box 200517, Helena, MT 59620-0517). Phone: (406) 841-2056, email: buildingcodes@mt.gov. Office hours: Mon–Fri, state business hours; online permitting available 24/7 via https://aca-prod.accela.com/bcb/. Official information: https://bsd.dli.mt.gov/building-codes-permits/.

    Unincorporated Yellowstone County, Montana has adopted: 2021 International Building Code (IBC) — adopted statewide by ARM Title 24, Chapter 301; effective June 11, 2022; 2021 International Residential Code (IRC) — ARM Title 24, Chapter 301; effective June 11, 2022; 2021 International Existing Building Code (IEBC) — ARM Title 24, Chapter 301; effective June 11, 2022; ICC A117.1-2017 (Accessibility) — ARM Title 24, Chapter 301; effective June 11, 2022; 2021 Uniform Plumbing Code (UPC) — ARM Title 24, Chapter 301; effective June 11, 2022 (fixture table at ARM 24.301.351); 2021 International Mechanical Code (IMC) — ARM Title 24, Chapter 301; effective June 11, 2022; 2021 International Fuel Gas Code (IFGC) — ARM Title 24, Chapter 301; effective June 11, 2022; 2020 National Electrical Code (NEC) — ARM Title 24, Chapter 301; effective June 11, 2022 (NEC Technical Advisory NEC_TIA-23-3_210.8 issued August 12, 2022); 2021 International Energy Conservation Code (IECC) — ARM Title 24, Chapter 301; effective June 11, 2022; 2021 International Swimming Pool and Spa Code (ISPSC) — ARM Title 24, Chapter 301; effective June 11, 2022; 2021 Wildland Urban Interface Code (WUIC) — ARM Title 24, Chapter 301; effective June 11, 2022; NOTE: All codes listed are statewide codes administered directly by the Montana Building Codes Bureau for areas (like unincorporated Yellowstone County) that are NOT within a certified local-government building code jurisdiction..

    The Montana Building Codes Bureau (state DLI), not Yellowstone County, since the county has not established a certified local plumbing-code enforcement program.

    Sources & verification

    Verified against official sources. Last reviewed 2026-07-02.

    Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Unincorporated Yellowstone County building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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