Does Idaho Have Emissions Testing?

As of July 1, 2023, Idaho does not require vehicle emissions testing. The Idaho Legislature passed legislation in 2022 to repeal the state requirement for vehicle Inspection and Maintenance (I/M) programs, effective July 1, 2023.

Program Administration History

Prior to the repeal, emissions testing in Idaho was overseen by:

Idaho Department of Environmental Quality (DEQ)
Air Quality Division
1410 N Hilton, Boise, ID 83706
Phone: (208) 373-0502
Official Website: Idaho Department of Environmental Quality

The DEQ administered the emissions testing programs and worked with local planning organizations to implement federal Clean Air Act requirements.

Idaho Transportation Department - Division of Motor Vehicles
Phone: (208) 584-4343
Official Website: Idaho Transportation Department

The Idaho Transportation Department (ITD) manages vehicle registration and titling, but does not currently require emissions testing as part of the registration process.

Legal Authority and Repeal

Idaho's former emissions testing program was established under Idaho Code Section 39-116B (Vehicle Inspection and Maintenance Programs). The program was originally implemented to comply with federal Clean Air Act requirements for areas not meeting national air quality standards.

Repeal Legislation: In 2022, the Idaho Legislature passed legislation repealing the state requirement for vehicle I/M programs, with an effective date of July 1, 2023. This action ended emissions testing requirements in Canyon County and the City of Kuna immediately on that date.

EPA Approval: Ada County's emissions program was subject to additional federal and local requirements. In June 2023, the EPA formally approved the removal of Ada County's emissions testing requirements, as documented in the Federal Register (June 15, 2023).

Reason for Repeal

According to the Idaho Department of Environmental Quality, modeling results demonstrated that I/M programs were no longer as effective as they once were due to:

• Vehicle turnover to newer, cleaner models
• Stricter federal motor vehicle emissions standards for new vehicles
• Improved air quality in the Treasure Valley over the past three decades
• The region currently meets all national health-based air quality standards

The state determined that the emissions testing program was no longer necessary to maintain air quality compliance.