Plumbing Permit in Unincorporated Yellowstone County, Montana
VerifiedPlumbing 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
- Required
Application for Plumbing Permit (BCP-1)
Signed by the Master Plumber performing the work (license number required) unless the owner-occupant exemption applies; filed with the Building Codes Bureau, PO Box 200517, Helena, MT 59620-0517, or online at aca-prod.accela.com/bcb
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Each plumbing fixture or trap | $10 per fixture | Montana 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. |
| Each new water heater or replacement | $25 | Same source, verbatim fee line item |
| Each connection of building water supply to water service/public utility or private well | $20 | Same source |
| Each connection of building drain to sewer system/public or septic | $20 | Same source |
| Gray water system (commercial or residential) | $60 | Same source |
| Repair or alteration of drainage or vent piping | $30 | Same source |
| Alteration or repair of water piping and/or treatment | $30 | Same source |
| Each storm drain and storm drainage | $30 | Same source |
| Each lawn sprinkler, fire protection system, meter, or backflow device | $30 | Same source |
| Each hose bibb, vacuum breaker, and/or backflow device | $6 | Same source |
| Each industrial water pre-treatment equipment (incl. drainage/vent) | $30 | Same source |
| Medical gas piping systems (per type) | $100 | Same source; additional $10 per outlet over 20 total outlets |
Review timeline
~1–5 business days
Typical estimate — confirm current times with the Unincorporated Yellowstone County building department
Inspection process
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.
- 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
- Do I need a plumbing permit to replace a water heater in unincorporated Yellowstone County?
- 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.
- Who issues plumbing permits in unincorporated Yellowstone County?
- 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.
- Montana Department of Labor & Industry — Building Codes Bureau (Business Standards Division, Building and Commercial Measurements Bureau) — official building department
- Montana Building Codes Bureau — Plumbing Permits (jurisdiction, exemptions)
- Montana Building Codes Bureau — Application for Plumbing Permit (ARM 24.301.301/24.301.361, Rev. 11/25) — verbatim fee schedule
- ARM 24.301.351 — Minimum Required Plumbing Fixtures (fixture table)
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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