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Montana, Yellowstone County HVAC Permit Regulations and County Ordinances for Unincorporated Areas

Yellowstone County HVAC Permit Requirements

In Yellowstone County, Montana, HVAC permit requirements are primarily handled by the State of Montana's Building Codes Division for properties in unincorporated areas. The City of Billings does not issue permits for construction outside of city limits. However, it's important to note that county ordinances and regulations may still apply.

For properties in unincorporated areas of Yellowstone County, the state program covers non-exempt commercial and multi-family (5+ units) buildings. Single-family residences (up to 4 units), farm/ranch buildings, private garages, and storage buildings are generally exempt from state permit requirements in these unincorporated areas.

While Yellowstone County itself does not issue building permits or certificates of occupancy for structures outside the city limits of Billings, you are encouraged to contact the City/County Planning Division, Riverstone Health, and Yellowstone County Public Works for guidance on applicable county ordinances and regulations.

Montana law requires HVAC contractors to hold a valid state license issued under Title 37, Chapter 68 before performing permitted mechanical work for compensation.

For specific installations and to determine the applicability of permit requirements, it is recommended to contact the Montana Building Codes Program or the Yellowstone County Public Works Department.

Rules for Properties in Unincorporated Areas

In unincorporated Yellowstone County, the State of Montana's Building Codes Division is responsible for issuing permits for non-exempt commercial and multi-family buildings.

Exemptions for properties in unincorporated areas include:

However, even for exempt structures, it is advisable to confirm with local authorities, as county ordinances may still apply.

Work performed in the public right-of-way within Yellowstone County always requires a permit, regardless of whether the property is in an incorporated or unincorporated area. This includes work on private and public accesses, utilities, and other construction within the right-of-way.

Resources to Learn More

Note: The following state-wide building codes and regulations apply universally to all jurisdictions within Montana, including Yellowstone County.

Montana Hvac Legislation, Codes, and Guidelines

Montana HVAC Building Codes and Legislation

The State of Montana enforces a statewide building code system that incorporates several model codes by reference. These codes are amended at the state level to address specific regional needs, such as snow loads and energy efficiency. For HVAC systems, the state has adopted the 2021 editions of the International Mechanical Code (IMC) and the International Fuel Gas Code (IFGC), along with the 2021 International Energy Conservation Code (IECC).

Regulatory Authority and Adoption

The primary agency responsible for establishing and enforcing these standards is the Montana Department of Labor & Industry (DLI), specifically through the Building Codes Program within the Business Standards Division. The state adopts these codes through the Administrative Rules of Montana (ARM), specifically under Title 24, Chapter 301. While the state sets the baseline, local jurisdictions (cities, counties, or towns) may be certified to enforce these codes locally. In areas without a certified local program, the state's Building Codes Program serves as the authority having jurisdiction.

Resources to Learn More

Select a City in Yellowstone County

If your project is located within incorporated city limits, you will likely need to follow municipal ordinances rather than county rules. Select your city below to view local regulations.

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