Utah requires vehicle emissions testing in five counties: Salt Lake, Davis, Utah, Weber, and Cache. If your vehicle is registered in one of these counties, you must pass an emissions inspection before you can renew your registration in the years your vehicle is due. Registered anywhere else in Utah? You can skip the test entirely.
How often does my vehicle need a test?
Every county follows the same rule for newer vehicles: for the first six model years, a vehicle tests once every two years. Even model years test in even calendar years, and odd model years test in odd years. A 2024 model tests in 2026, 2028, and so on.
Once a vehicle is six model years or older, the counties split:
| County | Vehicles 6+ model years old | Oldest tested model year |
|---|---|---|
| Salt Lake | Every year | 1968 |
| Davis | Every year | 1968 |
| Utah | Every year | 1968 |
| Weber | Every year | 1996 |
| Cache | Every two years (even/odd model year) | 1996 |
Cache County is the outlier in a good way: no vehicle registered there tests more often than every other year. For the full local rules, see our Cache County emissions guide.
Vehicles that never need a test
- Fully electric vehicles
- Motorcycles
- Model year 1967 and older vehicles
- Vehicles with vintage plates (model year 1982 and earlier)
- In Cache County, gasoline vehicles older than 1996
- Qualifying farm vehicles (application through your county health department)
How the test connects to your registration
The emissions certificate is sent to the Utah DMV electronically by the testing station, and it must be dated no more than two months before your registration renewal. Once your vehicle passes, you can renew online, at a DMV office, or on the spot with some testers. If you drive on expired tags while sorting this out, you risk a citation, so it pays to handle the test early in your renewal window. Our free registration reminder service texts you before your month arrives.
What the test involves for most vehicles
For 1996 and newer gasoline vehicles, the inspection is an OBD-II check: the tester connects to your vehicle's on-board diagnostics port and reads the emissions monitors. It takes about 15 minutes. There is no dyno run and no tailpipe probe for these vehicles. If your check engine light is on, the vehicle will not pass, so address that before testing. Our guide on what to do when a vehicle fails covers the common causes.
In Cache Valley, you do not even need to drive anywhere: we bring the test to your home or workplace for $49.99 with a free retest included.
Common Questions
Five counties require emissions testing as part of vehicle registration: Salt Lake, Davis, Utah, Weber, and Cache. If your vehicle is registered in any other Utah county, no emissions test is required.
If your vehicle is less than 6 model years old, it tests every two years: even model years in even calendar years, odd model years in odd years. Once a vehicle is 6 model years or older, Salt Lake, Davis, and Utah counties test it every year, while Cache County stays on the every-two-years schedule for all 1996 and newer vehicles.
Fully electric vehicles, motorcycles, vehicles from model year 1967 and older, and vehicles with vintage plates (1982 and earlier) are exempt. Brand new vehicles are covered by the two-year cycle for their first six model years, and in Cache County vehicles older than 1996 are no longer tested.
Your emissions test must be completed no more than two months before your registration renewal date. Results are sent to the DMV electronically, so once you pass you can renew online right away.