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Vehicle Emissions Testing in Idaho

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In Idaho, a vehicle emissions test is required for many original registrations, as well as for annual registration renewals, if the vehicle is registered in the Ada County. Renewal notices are sent annually to vehicle owners, and indicate whether and by what date an emissions test must be completed.


A vehicle requires an emissions test when:

  1. It is a 1965 model or newer.
  2. It is registered and driven mainly in the Ada County.
  3. It has a manufacturer's gross vehicle weight rating over 1500 pounds.


Emission tests are valid for 90 days. A valid test is required to reinstate a suspended registration and to complete an original vehicle registration or registration renewal. Used car dealers are required to issue a valid emissions test for any vehicle they sell. Getting an emissions test is the buyer's responsibility when the vehicle is purchased from a private owner.


A vehicle is exempt from emissions testing when:

  1. It is a 1964 model or earlier.
  2. It is not registered or used in the Ada County.
  3. It is a motorcycle or a motor-home.
  4. It is a new vehicle and less than a year old.
  5. It has a manufacturer's gross vehicle weight rating less than 1500 pounds.
  6. It is registered as an Idaho Old Timer or Classic Vehicle.
  7. It is a farm-tractor.
  8. It is a vehicle registered on pro-rated basis.
  9. It is an alternative fuel vehicle.


Any Authorized Emissions Inspection Station licensed by the Ada County can test your vehicle.


There is a maximum emissions testing fee of $15.00 set by the Air Quality Board of Idaho.


If your vehicle fails the emissions test, you must have the vehicle repaired, after which it must pass the after repairs emissions test. The vehicle can then be retested at an Authorized Emissions Inspection Station or a Repair and Re-Inspection Station by a qualified inspection mechanic.


  • If you are out of the Ada County, or your vehicle is otherwise unavailable for inspection at the time that the emission test is due, call the Ada County Air Quality Board at (208) 377-9191 for more information.
  • See also Vehicle History Reports.

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