Who has to get an emissions test in Utah
Utah requires emissions testing for most vehicles registered in Salt Lake, Davis, Weber, and Utah counties — the four counties in the Wasatch Front airshed where air quality is monitored. If you live outside these counties, you do not need a test. If you live in one of these counties and own a vehicle, you will need to pass an emissions test before you can renew your registration.
The requirement applies to gasoline-powered vehicles that are at least 6 model years old. A 2019 model year vehicle in 2025 would need testing; a 2020 model year would not yet. Diesel vehicles, motorcycles, and vehicles registered as classic or antique are exempt. If you own a vehicle that is less than 6 years old, you do not need to test it during that window, but you will once it ages into the requirement.
New residents moving into a Wasatch Front county must pass an emissions test within 60 days of registering their vehicle in Utah, regardless of the vehicle's age or model year. This is a separate rule from the age-based requirement.
Key Takeaways
- Emissions testing is required only in Salt Lake, Davis, Weber, and Utah counties; all other Utah counties do not require it.
- Your vehicle must be at least 6 model years old to fall under the regular testing requirement, though new residents must test within 60 days regardless of age.
- You can test at any of Utah's certified emissions testing stations, and the test costs between $20 and $30 depending on the station.
- Your vehicle must pass before you can renew your registration, and you should plan to test at least two weeks before your registration expires.
- If your vehicle fails, you have 60 days to repair it and retest at no additional charge at the same station.
Where to find a testing station and what to bring
Utah maintains a list of certified emissions testing stations on the Utah Division of Air Quality website. You can search by county or city to find stations near you. Most stations are independent repair shops, tire shops, or quick-lube facilities that have been certified to perform the test. Call ahead to confirm hours and whether they accept walk-ins or require an appointment — many stations book up during peak times, especially in the weeks before registration important date.
Bring your vehicle registration or proof of ownership, a valid photo ID, and your vehicle's keys. The station will need to plug a diagnostic scanner into your vehicle's onboard computer to read emissions data. The test itself takes 10 to 15 minutes. You do not need to bring any paperwork related to maintenance or repairs unless your vehicle previously failed and you are retesting.
The test costs between $20 and $30 depending on which station you choose. Prices are set by individual stations, not by the state. Some stations may charge slightly more if they perform repairs on your vehicle at the same visit, but the emissions test itself should not exceed $30.
When you must test and how it connects to registration renewal
You must pass an emissions test before you can renew your vehicle registration. Utah's registration system will not allow you to complete a renewal online or at a DMV office until a passing test result is on file. This means you need to test before your current registration expires, not after.
Plan to test at least two weeks before your registration expires. This gives the testing station time to report the result to the state system and gives you a buffer if your vehicle fails and needs repair. If you test in the final week before expiration and fail, you may not have time to fix the vehicle and retest before your registration lapses.
You can test up to 120 days before your registration expires. Testing earlier than that will result in a test result that is too old to use for renewal. If you test 121 days early and your registration does not expire for another 150 days, you will need to test again closer to the expiration date.
What happens if your vehicle fails the test
If your vehicle fails, the testing station will provide you with a failure report that lists the specific emissions systems or components that did not meet standards. Common failure reasons include a faulty oxygen sensor, a malfunctioning catalytic converter, or an engine control module problem. The report will tell you what failed, but not always how to fix it — that is a question for a repair shop.
You have 60 days from the date of the failed test to repair your vehicle and retest at the same station. The retest is free if you return to the same station where you originally failed. You do not need to wait for the repairs to be complete before scheduling a retest; you can retest as soon as you believe the issue is fixed. If you retest and still fail, you have another 60 days from that second test date to repair and test again.
If your registration expires before you pass a retest, your registration will lapse and you cannot legally drive the vehicle. You will need to pass the emissions test, then renew your registration, before you can drive again. This is why testing early is important — it prevents a situation where a failed test and repairs push you past your registration expiration date.
Vehicles that are exempt from testing
Diesel vehicles do not require emissions testing in Utah, even if they are registered in a Wasatch Front county and are older than 6 model years. Motorcycles and mopeds are also exempt. Vehicles registered as classic or antique — typically vehicles 25 years or older — are exempt from testing.
Electric vehicles and hybrid vehicles are exempt from emissions testing. Vehicles with a gross vehicle weight rating over 14,000 pounds (most pickup trucks and commercial vehicles) are exempt. If you are unsure whether your vehicle qualifies for an exemption, contact the Utah Division of Air Quality or ask the testing station when you call to schedule.
What the test actually measures
The emissions test measures the amount of nitrogen oxides, carbon monoxide, and hydrocarbons your vehicle's exhaust produces. The vehicle's onboard diagnostic system is scanned to check for emissions-related fault codes. The test does not measure fuel economy, safety features, or mechanical condition — it measures only whether your vehicle's emissions systems are working within state standards.
For most vehicles, the test is performed while the vehicle is idling and during a short acceleration cycle. The scanner reads data from your engine's computer and compares it to the standards for your vehicle's model year and engine type. Standards are stricter for newer vehicles than for older ones, so a 2015 model year vehicle must meet tighter limits than a 2005 model year vehicle.
Frequently Asked Questions
Can I test my vehicle in a different county than where it is registered?
Yes. You can test at any certified station in Utah, regardless of which county your vehicle is registered in. However, you must still test in one of the four Wasatch Front counties (Salt Lake, Davis, Weber, or Utah) if that is where your vehicle is registered. If your vehicle is registered outside those counties, you do not need to test anywhere.
What if I just moved to Utah and my vehicle is only 2 years old?
New residents must test within 60 days of registering their vehicle, regardless of age. Your 2-year-old vehicle will need to be tested even though it would not normally require testing for several more years. After that first test, you will follow the regular 6-year-old rule for future renewals.
Do I need to test if I am renewing my registration online?
Yes. You must have a passing emissions test result on file before you can complete any registration renewal, whether online or in person. The online system will not allow you to finish the renewal until the test is recorded in the state database.
What if the testing station says my vehicle cannot be tested because the check engine light is on?
A lit check engine light does not automatically disqualify your vehicle from testing. However, if the light is on because of an emissions-related fault code, the vehicle will likely fail the test. The station can scan your vehicle to see what code triggered the light. If it is emissions-related, you will need to repair it before a passing test is possible.
How long does a passing test result stay valid?
A passing test result is valid for 120 days. After 120 days, you will need to test again before you can renew your registration. If your registration does not expire within 120 days of your test, you will need to test again closer to the expiration date.