Emissions testing is a requirement for residents in Ada and Canyon counties and the City of Kuna in Idaho before every registration renewal period. Inspections help to reduce harmful air pollutants that contribute to poor health and improve air quality. However, the Air Quality Board (AQB) oversees Ada County smog checks, while vehicle inspections in Canyon County and the City of Kuna are overseen by the state Department of Environmental Quality (DEQ)

In most cases, vehicles must undergo an emissions inspection every other year, regardless of which county the vehicle owner resides in. To learn more about vehicle emissions testing in ID, review the sections below.

Idaho Emissions and Smog Check Requirements

Drivers must complete vehicle smog testing once every 2 years to avoid having their vehicle registration revoked. As a reminder, residents receive an Idaho emissions testing notice from the AQB or the DEQ before the test is due. Vehicle owners may visit a testing station to complete their car inspection up to 90 days before the test due date if they live in Canyon County or the City of Kuna. However, the smog certification process is similar regardless of whether vehicle owners live in Canyon or Ada County.

The AQB and DEQ tests gasoline-powered vehicles using the two-speed idle test (TSI) or an onboard diagnostic system (OBD). Auto emissions testing includes the TSI test when inspecting vehicles manufactured between 1981 and 1995, while the DEQ uses the OBD method on vehicles manufactured after 1996. To test diesel vehicles, the DEQ uses a snap acceleration test. Additionally, the state inspects gas caps for leaks.

Vehicle owners must complete smog testing in Idaho if their vehicles meet the following conditions:

  • The vehicle is registered in Canyon County and is a diesel or gasoline-powered vehicle manufactured after 1981 and is at least 5 years old.
  • The vehicle is registered in Ada County and was manufactured after 1981. Drivers of heavyweight vehicles including firetrucks and buses must also test their vehicles for harmful emissions.

Note: When you visit an emissions testing center, you must bring payment for testing fees. The state sends vehicle owners a notice before testing is due, but drivers do not need to submit this notice when completing the inspection.

Smog Check Exemptions in Idaho

Safety and emissions test exemptions vary depending on whether motorist lives in Ada County or Canyon County. The following vehicles are exempt from a testing in Ada County:

  • Hybrid or electric vehicles
  • Motorhomes
  • Vehicles with a gross vehicle weight of less than 1,500 lbs.

The following vehicles are exempt from an Idaho DMV smog check in Canyon County or the City of Kuna:

  • electric or hybrid vehicles
  • motorized farm equipment or vehicles used solely for agriculture
  • motorhomes
  • vehicles with a gross vehicle weight rating of 14,001 lbs or greater
  • Motor vehicles with a gross vehicle weight of less than 1,500 lbs.

Additional safety and smog test exemptions in Canyon County are made for classic automobiles, vehicles less than 5 years old and vehicles manufactured before 1981.

Out-of-State Emissions Testing in Idaho

Military personnel and out-of-state college students may complete the Idaho smog testing process from out-of-state if they visit a participating testing facility. To complete a vehicle inspection in compliance with Ada County testing requirements, vehicle owners may complete the test while out-of-state by visiting a testing center in the area and forwarding a copy of the test to the AQB by mail, fax or email. If the state where the ID resident is does not perform emissions testing, drivers must contact the AQB to request an extension.

To complete a smog inspection from out-of-state to meet Canyon County or City of Kuna requirements, drivers must obtain a Reciprocity Agreement Form and bring it to a local testing facility to complete the inspection. After passing the vehicle emission test, car owners must scan and email a copy of the inspection certificate to Applus Technologies.

Emissions Waivers in Idaho

In many cases, vehicle owners may obtain the following ID emissions testing waivers in Canyon County or the City of Kuna:

  • An economic hardship waiver – drivers undergoing financial difficulties may obtain an economic hardship waiver after submitting documentation of income and expenses.
  • A repair waiver – after failing an emissions inspection for the second time and spending at least $200 on emissions-related repairs, car owners may obtain a repair waiver.

Additionally, drivers may obtain a repair waiver in Ada County if they spend at least $300 on necessary vehicle repairs but still fail the test. 

Testing Fees in Idaho

The emission test cost in Ada County ranges between $16.50 and $20, while the test is $11 in Canyon County and the City of Kuna. After a vehicle passes its Idaho smog check or receives a waiver in Ada County, vehicle owners must pay an additional $3.50 to obtain a Certificate of Compliance, which drivers must keep in the vehicle.

Where to Perform an Emissions Check in Idaho

To perform an emissions check in Canyon County or the City of Kuna, you may visit any of the 20 emissions testing stations provided by approved small businesses throughout the county. To perform a test in Ada County, you must visit one of the 50 testing stations available throughout the county. However, certain emissions testing locations in Idaho only perform repairs and retests, so it is important to contact the station ahead of time to confirm.

Failing an Idaho Smog and Emissions Test

If a vehicle fails its smog check in Idaho, drivers must make every effort to repair the vehicle before bringing it in for a retest. However, most test stations do not perform car repairs or provide advice for making repairs.

Instead, vehicle owners must bring their vehicles into a qualified technician with experience in making emissions-related repairs. After making all necessary repairs, drivers may return to the initial testing station to complete the retest. Motorists receive one free retest within 30 days of taking the initial test.

Last updated on Monday, March 11 2019.

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