Mobile Car Wash Permit Requirements in Missoula, MT

1. EIN (Employer Identification Number)

   Required if you have employees or operate as an LLC or corporation. Free from the IRS, obtained instantly online.

   Official government source

   Free·Immediate (online application)

   Free

   Immediate (online application)

2. EPA Stormwater Compliance — Clean Water Act Section 402

   Mobile car wash operations that discharge wash water are subject to the federal Clean Water Act. The EPA's National Pollutant Discharge Elimination System (NPDES) prohibits discharge of polluted wash water to storm drains or waterways without a permit. Most mobile operators achieve compliance by using containment systems and disposing of water via sanitary sewer. Larger operations (e.g., fleet washing facilities) may require an NPDES permit.

   Official government source

   Free (containment equipment: $200–$1,500)·Before first wash

   Free (containment equipment: $200–$1,500)

   Before first wash

1. Montana Business Registration

   Mobile car wash and auto detailing businesses structured as an LLC, corporation, or partnership must register with the Montana Secretary of State (online via sosmt.gov). Sole proprietors operating under a business name file an assumed business name registration with the Secretary of State. An LLC is recommended to protect personal assets for mobile operations working on customers' property.

   Official government source

   $35 LLC Articles of Organization (online); $20 assumed business name·1–7 business days

   $35 LLC Articles of Organization (online); $20 assumed business name

   1–7 business days

2. Montana Environmental / Stormwater Compliance

   Mobile car wash operations generate wastewater containing detergents, surfactants, oils, and road grime. Montana environmental regulations — consistent with federal Clean Water Act requirements — prohibit discharge of this wash water to storm drains, street gutters, or waterways. Operators must use a wastewater containment mat and recovery system (wet/dry vacuum or pump), or must ensure wash water flows to a sanitary sewer inlet. Operators using hazardous cleaning solvents or degreasers may require a state permit. Contact the Montana Department of Environmental Quality for compliance guidance.

   Official government source

   Free–$200 (registration or permit fee, if required)·1–4 weeks (if permit required; otherwise immediate with self-compliance)

   Free–$200 (registration or permit fee, if required)

   1–4 weeks (if permit required; otherwise immediate with self-compliance)

1. Missoula General Business License

   All mobile car wash and auto detailing businesses operating in Missoula must obtain a general business license from the city. Mobile operations that travel to customers throughout the city are covered by a single city license. The application requires your business entity information, contact details, and a description of services. Renewed annually.

   Official government source

   $60 per FTE for a commercial location (minimum $240) or $40/FTE home-based (minimum $160); renewal $27/FTE (minimum $108) — CY2026 fee schedule·1–2 weeks

   $60 per FTE for a commercial location (minimum $240) or $40/FTE home-based (minimum $160); renewal $27/FTE (minimum $108) — CY2026 fee schedule

   1–2 weeks

2. Missoula Stormwater / Wastewater Discharge Compliance

   Missoula prohibits the discharge of mobile car wash wastewater into storm drains, gutters, or waterways. Wash water contains detergents, oils, and road grime that are harmful to local waterways. Operators must: (1) use a portable containment berm or mat to capture runoff, (2) vacuum up wash water with a wet/dry vac or pump, and (3) dispose of collected water at an approved sanitary sewer access point or licensed disposal facility. The city's Public Works or Stormwater division may conduct inspections. Violations may result in fines.

   Official government source

   $0 — no registration or inspection fee is published; the obligation is compliance with the city's stormwater ordinance: capture wash water and dispose to the sanitary sewer·1–3 weeks (self-certify compliance before operating)

   $0 — no registration or inspection fee is published; the obligation is compliance with the city's stormwater ordinance: capture wash water and dispose to the sanitary sewer

   1–3 weeks (self-certify compliance before operating)

3. Chemical handling: OSHA hazard communication and proper disposal (no county registration)

   Missoula County has no chemical-use registration for detailing businesses. Businesses using cleaning chemicals must follow OSHA hazard-communication requirements (Safety Data Sheets available to employees) and dispose of solvents and degreasers properly — never to storm drains; Missoula Public Health offers household/business chemical disposal guidance.

   Official government source

   $0 — no registration exists·1–2 weeks

   $0 — no registration exists

   1–2 weeks

4. Missoula Home-Based General Business License (zoning home-occupation standards apply)

   A mobile car wash operator based at a Missoula residence licenses as a home-based General Business License ($40/FTE, minimum $160 new; renewal $27/FTE, minimum $108) and must comply with zoning home-occupation standards (limits on outside storage, traffic, and signage). There is no separate home-occupation permit fee.

   Official government source

   $40 per FTE (minimum $160) new; renewal $27/FTE (minimum $108) — CY2026 fee schedule·1–3 weeks

   $40 per FTE (minimum $160) new; renewal $27/FTE (minimum $108) — CY2026 fee schedule

   1–3 weeks

Official Sources

• Missoula Business Licensing
• Montana Environmental Quality — Water Programs
• EPA NPDES — Stormwater Discharges
• IRS EIN Application

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