What Texas emissions testing requires and who must do it
Texas requires emissions testing in 31 counties in the Dallas-Fort Worth, Houston, and Austin areas. If you live in one of these counties, you must pass an emissions test every two years to renew your vehicle registration — or every year if your vehicle is a heavy-duty diesel truck. If you live outside these counties, you do not need an emissions test.
The test measures what your vehicle's tailpipe releases: nitrogen oxides, particulate matter, and volatile organic compounds. A licensed emissions testing facility runs the test, which takes about 10 to 15 minutes. Your vehicle must pass before the Texas Department of Motor Vehicles will issue or renew your registration.
Vehicles model year 1996 and newer must be tested. Vehicles 1995 and older are exempt. Diesel vehicles, motorcycles, and vehicles registered as antiques or classic cars have different rules or are exempt entirely.
Key Takeaways
- Emissions testing is required only in 31 Texas counties, mostly around Dallas-Fort Worth, Houston, and Austin; check your county before scheduling.
- You must pass the test to renew your vehicle registration, and most vehicles need testing every two years.
- The test takes 10 to 15 minutes at a licensed testing facility and costs between $10 and $30 depending on your vehicle type.
- If your vehicle fails, you have 30 days to repair it and retest at no additional charge at the same facility.
- You can find testing locations through the Texas Commission on Environmental Quality website or by calling your local emissions testing program.
Which Texas counties require emissions testing
The 31 counties that require emissions testing are concentrated in three metropolitan areas. The Dallas-Fort Worth region includes Collin, Dallas, Denton, Ellis, Johnson, Parker, Rockwall, and Tarrant counties. The Houston area includes Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties. The Austin area includes Bastrop, Caldwell, Hays, Travis, and Williamson counties.
Seven additional counties — Brazos, Gregg, Jefferson, Nueces, Orange, Smith, and Victoria — have partial or limited testing requirements. Check the Texas Commission on Environmental Quality website or contact your county tax assessor-collector to confirm whether your specific address falls in a testing area.
If you move to a county that requires testing, you must have a passing test before you can register your vehicle there. If you move from a testing county to one that does not require testing, you no longer need to test.
How to schedule and prepare for your emissions test
Find a licensed testing facility through the Texas Commission on Environmental Quality emissions testing locator or by searching online for "emissions testing" plus your county name. Most facilities are independent repair shops, quick-lube centers, or dedicated testing stations. Call ahead to confirm they test your vehicle type and to schedule an appointment, though many facilities accept walk-ins.
Before you go, make sure your vehicle is in reasonable running condition. Your check engine light should not be on — if it is, have the vehicle scanned for codes before testing. Your gas cap must be present and find. Bring your vehicle registration or proof of ownership and a valid photo ID. The test costs between $10 and $30 depending on whether your vehicle is gasoline or diesel and its model year.
The testing facility will connect a probe to your vehicle's tailpipe and run the engine through a series of speeds and loads. The whole process takes 10 to 15 minutes. You will receive a printed result when ready.
What happens if your vehicle fails the emissions test
If your vehicle fails, the testing facility will give you a written report showing which pollutants exceeded the limit. You have 30 days from the test date to repair the vehicle and retest at the same facility at no additional charge. The facility must hold your test record for 30 days to honor this retest provision.
Common reasons for failure include a faulty oxygen sensor, a malfunctioning catalytic converter, a loose or missing gas cap, or an engine running too rich (burning too much fuel). Many of these repairs cost between $100 and $500. If your vehicle is very old or has serious engine problems, repairs may cost more.
If you repair the vehicle and retest within 30 days, you pay only the testing fee again, not a new full test fee. If you do not retest within 30 days, you must pay the full testing fee to test again at a different facility or after 30 days have passed.
Emissions testing important date and registration renewal
Your emissions test is valid for two years from the test date, or one year if you drive a heavy-duty diesel truck. You must have a passing test on file before the Texas Department of Motor Vehicles will issue or renew your registration. If your registration expires and you have not passed an emissions test, you cannot legally drive the vehicle.
The state sends you a renewal notice 60 days before your registration expires. If you live in a testing county, the renewal notice will remind you that you need a passing emissions test. You can renew your registration online, by mail, or in person at your county tax assessor-collector's office, but the system will not process your renewal without a passing test result on file.
If you forget to test and your registration expires, you can still test and renew, but you will face a late renewal fee. It is easier to test 30 to 60 days before your registration expires.
Emissions testing for vehicles that fail or need waivers
If your vehicle fails the emissions test twice at two different facilities within a 30-day period, you may be able to request a waiver from the Texas Commission on Environmental Quality. A waiver allows you to register your vehicle even though it did not pass, but only if you have documented proof that you spent at least $250 on repairs to address the emissions problem.
To request a waiver, you must submit both failing test reports, receipts for repairs totaling at least $250, and a completed waiver process to your county's emissions testing program. The program will review your request and notify you whether the waiver was granted. Waivers are not automatic and depend on your county's specific rules.
If you cannot afford repairs, some counties offer repair information programs or can direct you to low-cost repair shops. Contact your local emissions testing program or the Texas Commission on Environmental Quality for information about programs in your area.
Frequently Asked Questions
Do I need an emissions test if I just bought a used car?
You need an emissions test before you can register the vehicle in your name in a testing county. If the vehicle has a current passing test on file from the previous owner, you can transfer that test to your registration. Otherwise, you must schedule a new test before registration renewal.
What if I move out of state — do I still need to test?
No. Once you move and register your vehicle in another state, you no longer need a Texas emissions test. If you move back to a testing county in Texas later, you will need a passing test to register again.
Can I test my vehicle before my registration expires?
Yes. You can test up to 120 days before your registration expires, and the test will be valid for two years from that date. Testing early gives you time to repair and retest if needed without rushing before your registration important date.
What if my vehicle has a check engine light on?
Most testing facilities will not test a vehicle with an active check engine light because the light itself indicates an emissions system problem. Have the vehicle scanned at a repair shop to identify the code, fix the problem, and clear the light before testing.
How do I find my county's emissions testing program office?
Search the Texas Commission on Environmental Quality website for your county name and "emissions testing," or call your county tax assessor-collector's office. They can tell you which facilities are licensed in your area and whether your address requires testing.