Oregon, Multnomah HVAC Permit Regulations and County Ordinances for Unincorporated Areas

Multnomah County HVAC Permit Requirements

Multnomah County is responsible for issuing building permits and maintaining permit records specifically for unincorporated areas within the county. For properties located within city limits, such as Portland or Gresham, you will need to contact the respective city's building department for permit information.

When applying for a building permit in unincorporated parts of Multnomah County, the city will refer you to the county to submit your building plan for zoning rule compliance review.

Unincorporated Areas

Multnomah County issues permits and maintains records for unincorporated areas only. These are areas located outside of any incorporated city.

The City of Portland administers the Portland Zoning Code for specific areas of Unincorporated Multnomah County.

General HVAC Permit Information for Oregon

In Oregon, a mechanical permit is required for HVAC installations, replacements, or alterations to ensure compliance with the Oregon Mechanical Specialty Code (OMSC).

A mechanical permit is required for work on heating or cooling systems, including installations or modifications involving ductwork, or systems that vent into a chimney or other exhaust vent. It is also required for work with fuel or gas, such as installing, repairing, or altering gas piping, or installing a wood stove or fireplace insert.

Even if a building permit is not required, a mechanical permit may still be necessary for certain HVAC work.

Homeowners can perform their own mechanical work but must still obtain the required permits and pass inspections.

Contractors performing mechanical work in Oregon must hold a valid Oregon Construction Contractors Board (CCB) license and, for systems containing refrigerant, an EPA Section 608 certification.

Permit requirements are largely uniform across Oregon, with local variations typically limited to fees, application procedures, and supplemental documentation.

Oregon law requires permits for various installations, alterations, and construction on homes to ensure work meets minimum safety standards. Permits are required for new construction and specific alterations, including structural, plumbing, mechanical, and electrical changes. The individual performing the work, whether a homeowner or contractor, is responsible for obtaining all necessary permits.

Permits expire if work is not started within 180 days of issuance or if work is suspended or abandoned for more than 180 days. Extensions may be requested from the local building official.

Resources to Learn More

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

Oregon Hvac Legislation, Codes, and Guidelines

Oregon HVAC Building Codes and Legislation

Oregon regulates heating, ventilation, and air conditioning (HVAC) systems through a series of state-specific specialty codes. These codes are updated periodically to incorporate modern standards, energy efficiency requirements, and safety protocols. As of April 2026, the primary codes governing mechanical systems in the state include the 2025 Oregon Mechanical Specialty Code (OMSC) and the 2023 Oregon Residential Specialty Code (ORSC).

The 2025 OMSC, which became mandatory on April 1, 2026, is based on the 2024 editions of the International Mechanical Code (IMC) and the International Fuel Gas Code (IFGC), with specific Oregon amendments. For residential construction, the 2023 ORSC provides the governing standards. Recent legislative and regulatory updates have introduced significant changes, including new requirements for heat pumps in certain new residential construction projects where split-system air conditioning is installed, aimed at improving energy efficiency and reducing long-term utility costs for homeowners.

Primary Regulatory Agencies

The administration and adoption of these building codes are managed by the following state entities:

Resources to Learn More

Select a City in Multnomah

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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