Smog & Emission Checks

Tennessee has a vehicles emissions testing program to improve air quality in the state. Below are some of the most frequently asked questions about testing in Tennessee.

What's the point of an emissions test?

There are a few, actually. Emissions testing improves air quality, cuts back on ground-level ozone pollution, and lets the owner know of any repairs that the vehicle may need.

Plus, you are also saving yourself some money. Your vehicle's engine will burn fuel more efficiently if maintained, and making the most of fuel will help you save money on skyrocketing gas prices.

Does everyone have to have an emissions test?

No. Only gas or diesel-fueled vehicles weighing up to 10,500 pounds, that will be registered in Davidson, Hamilton, Rutherford, Sumner, Williamson, and Wilson counties, as well as those registered in Memphis, will have to undergo emissions testing before they can be registered or have their registrations renewed.

If your vehicle is new and has never been titled, an emissions test isn't required to apply for a new title. Instead, take the Manufacturer's Certificate of Origin (MCO) to your local county clerk's office. Emissions tests will be required every year after that.

In Middle Tennessee, vehicles made in 1974 and earlier aren't required to pass emissions tests, but in Memphis, all model years of vehicles weighing less than 26,000 pounds must pass an emissions test.

Are there any other testing exemptions besides vehicles not registered in those counties?

Yes. Motorcycles are exempt, as are vehicles currently out of state or out of the testing area. Instructions and applications for temporary exemptions are available online. Davidson County residents should call (615) 340-5656; all other counties you may call (615) 532-0534 for more information.

What if I'm in another state?

If you're out of state or out of the testing area, when it's time to test you should apply for a temporary exemption.

When do I have to test?

You'll need to have your vehicle tested before you register it and before you renew your registration. The state advises drivers to come early in the month on Thursday or Friday afternoon, or on a Saturday.

Where do I test?

Each county has at least one testing station, and Tennessee provides an online list of all stations available in your county, the days and hours each one is open, and a closed holiday schedule.

How much does emissions testing cost?

The fee is $10, and can only be paid in cash using bills no larger than $20. Checks, money orders, and credit cards will not be accepted.

What happens during an emissions test?

Your catalytic converter and fuel gas cap will be checked. Estimated testing time is five minutes.

What happens if my vehicle fails the emissions test?

Well, there is some good news―you'll be set up with free diagnostic help by an ASE certified mechanic who can help determine why your vehicle won't pass.

Just call 532-TEST if you're in Rutherford, Sumner, Williamson, or Wilson, or (866) 329-9632 if you're in Hamilton County or out of Middle Tennessee's dialing area.

What is the onboard diagnostic testing?

Onboard diagnostic testing came into effect on June 1, 2002, and only applies to vehicles that were made in 1996 or after.

The test checks for gas cap leaks, as well as whether the vehicle's malfunction indicator light is working. The vehicle's computer system will be checked, too.

How do I report a gross polluter?

Keeping Tennessee's air clean is important. If you suspect a gross polluter, contact the Division of Air Pollution Control at (615) 532-0554.

Who can I contact for more information?

Contact the Division of Air Pollution Control (APC) at (615) 532-0554, or visit or write to the division at:

• Division of Air Pollution Control

• Barry R. Stephens, Director

• 9th Floor, L & C Annex

• 401 Church St.

• Nashville, TN 37243-1531

Additional Air Quality Resources

• The U.S. Environmental Protection Agency's Air Programs

• Southeastern APC Agencies Training and Information

• Tennessee's Air Permitting Handbook

• Visible Emissions Evaluation (Smoke School)

• Tennessee's Air Regulations