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?
Four of the five counties share one schedule. Vehicles under six model years old test once every two years: even model years in even calendar years, odd model years in odd years, so a 2024 model tests in 2026, 2028, and so on. Once a vehicle is six model years or older, it tests every year.
Cache County is the exception. Newer vehicles are exempt for their first six model years, and after that they test every other year on the same even/odd schedule.
| County | Under 6 model years | 6+ model years |
|---|---|---|
| Salt Lake | Every other year | Every year |
| Davis | Every other year | Every year |
| Utah | Every other year | Every year |
| Weber | Every other year | Every year |
| Cache | Exempt | Every other year |
In every county, model year 1995 and older vehicles are not tested; Davis County ended its tailpipe testing for those vehicles on October 1, 2026. 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 and Davis County emissions guides.
Vehicles that never need a test
- Fully electric vehicles
- Motorcycles
- Model year 1995 and older vehicles, in every testing county
- In Cache County, vehicles in their first six model years
- 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.
It depends on your county and model year. In Salt Lake, Davis, Utah, and Weber counties, vehicles under 6 model years old test every other year (even model years in even calendar years, odd in odd) and vehicles 6 or more years old test every year. Cache County exempts the first 6 model years entirely, then tests every other year. Vehicles from 1995 and older are not tested in any county.
Fully electric vehicles, motorcycles, and qualifying farm vehicles are exempt. Brand new vehicles are not tested in their first model years, and in Cache County a vehicle is exempt for its first 6 model years. Vehicles from model year 1995 and older are not tested in any county.
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.