What Texas Emissions Inspections Require
Texas requires an emissions inspection (also called a smog check) for vehicles registered in 31 counties in the Dallas-Fort Worth, Houston, Austin, and San Antonio areas. If you live outside those counties, you do not need one. The inspection tests whether your vehicle's exhaust meets state pollution standards — it does not check brakes, tires, or safety equipment.
The inspection takes about 10 to 15 minutes and costs between $25 and $50 depending on your vehicle type and the testing station. A technician will plug a diagnostic scanner into your vehicle's onboard computer to read emissions data, then run a tailpipe test to measure what comes out. You pass or fail based on those readings alone.
You must have a current inspection before you can renew your vehicle registration in one of the regulated counties. If your inspection expires, you cannot legally register the vehicle, and driving it is a violation.
Key Takeaways
- Texas emissions inspections are required only in 31 counties in the Dallas-Fort Worth, Houston, Austin, and San Antonio areas; check your county on the Texas Commission on Environmental Quality website to confirm.
- The inspection tests your vehicle's exhaust against state pollution standards and takes 10 to 15 minutes at a licensed testing station.
- You must pass an emissions inspection before you can renew your vehicle registration in a regulated county.
- If your vehicle fails, you have 60 days to repair it and retest at no additional cost at the same station.
- Diesel vehicles, motorcycles, and vehicles over 25 years old are exempt from emissions testing in Texas.
Which Texas Counties Require Emissions Testing
The 31 counties that require emissions inspections are concentrated in four metropolitan areas. The Dallas-Fort Worth region includes Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, and Tarrant counties. The Houston area covers Brazoria, Chambers, Fort Bend, Galveston, Harris, Liberty, Montgomery, and Waller counties.
The Austin region includes Bastrop, Caldwell, Hays, Travis, and Williamson counties. The San Antonio area covers Bexar, Comal, Guadalupe, and Wilson counties. If your vehicle is registered in any of these counties, you need an inspection. The Texas Commission on Environmental Quality (TCEQ) maintains the official list on its website, where you can search by county name.
If you move from a regulated county to a non-regulated one, or vice versa, your inspection requirements change based on where you register your vehicle, not where you currently live.
How to Find a Testing Station and Schedule
You can test at any licensed emissions testing station in your county — you do not have to go to a specific location. The TCEQ website has a searchable directory of all licensed stations, organized by county. Most stations are independent repair shops, quick-lube facilities, or dedicated inspection centers.
Many stations accept walk-ins during business hours, though some require appointments. Call ahead to confirm hours and whether you need to book a time. Bring your vehicle keys and proof of vehicle ownership or registration. The inspection itself takes 10 to 15 minutes, and you will receive a pass or fail notice on the spot.
If you pass, the station will electronically submit your results to the TCEQ within one business day. Your inspection is then valid for two years from the test date. You do not receive a physical sticker or certificate — the inspection is recorded in the state system and linked to your vehicle's registration.
What Happens If Your Vehicle Fails
If your vehicle fails the emissions test, the station will give you a detailed report showing which emissions standards were not met. You then have 60 days to repair the vehicle and retest. The retest is free at the same station where you failed, even if you take the vehicle elsewhere for repairs.
Common reasons for failure include a faulty oxygen sensor, a loose or missing gas cap, a malfunctioning catalytic converter, or an engine control light that is on. Many of these repairs cost $100 to $500, though catalytic converter replacement can be significantly more. Some repair shops offer free or low-cost diagnostics to identify the problem before you pay for repairs.
If you retest within 60 days and pass, your new inspection date becomes valid for two years. If you do not retest within 60 days, you cannot renew your registration until you pass an inspection. You can retest as many times as needed within that 60-day window at no additional charge.
Vehicles Exempt from Emissions Testing
Diesel-powered vehicles are exempt from emissions testing in Texas, regardless of which county they are registered in. Motorcycles and mopeds are also exempt. Vehicles manufactured more than 25 years ago are exempt as well — for example, any vehicle made before 1999 does not need an inspection in 2024.
Electric vehicles do not require emissions testing because they produce no tailpipe emissions. Hybrid vehicles that still have a gasoline engine do require testing. If you are unsure whether your vehicle qualifies for an exemption, the TCEQ website lists all exemption categories, or you can ask a testing station when you call.
Timing Your Inspection Before Registration Renewal
Your emissions inspection is valid for two years from the test date. You should schedule your inspection before your vehicle registration expires, because you cannot renew registration without a passing inspection on file. The Texas Department of Motor Vehicles will not process a registration renewal if your inspection has failed or expired.
You can take your inspection test anytime during the two-year window — there is no requirement to wait until close to your registration expiration date. Many people test early to avoid the rush near renewal important date. If your inspection expires before you renew your registration, you must retest before the registration renewal can go through.
When you renew your registration online, by mail, or at a DMV office, the system will check whether a valid inspection is on file. If one is not, your renewal will be rejected, and you will be directed to get tested first.
What to Do If You Disagree With a Failed Inspection
If you believe your vehicle was tested incorrectly or the results are wrong, you have the right to request a retest at a different station. The TCEQ does not charge for a second opinion test. Take your vehicle to another licensed testing station in your county and explain that you want an independent retest. That station will run the full inspection again.
If the second test also shows a failure, the results stand and you will need to repair the vehicle. If the second test shows a pass, you can use that passing result for your registration. Keep both test reports in case questions arise later. The TCEQ also has a complaint process if you believe a testing station violated procedures, though this is separate from disputing test results.
Frequently Asked Questions
Can I test my vehicle in a different county than where it is registered?
No. You must test in the county where your vehicle is registered. If you move to a different county, you will need to update your registration first, then test in your new county. Testing in the wrong county will not count toward your registration renewal.
What if I buy a used car and it has a failed inspection on record?
The failed inspection belongs to the previous owner and does not transfer to you. When you register the vehicle in your name, you will need a new inspection. If the vehicle has a recent failed inspection, you may want to have it inspected by a mechanic before purchase to understand what repairs are needed.
Do I need an inspection if I only drive my registered vehicle occasionally?
Yes. If your vehicle is registered in a regulated county, you must have a valid inspection to renew your registration, regardless of how often you drive it. The inspection requirement is tied to registration, not to actual vehicle use.
What happens if I drive without a valid inspection in a regulated county?
Driving a vehicle with an expired or failed inspection in a regulated county is a violation. You can receive a citation, and your vehicle registration may be suspended. The safest approach is to schedule your inspection before your current one expires.
Can I get an inspection extension if I am waiting for repair parts?
No. The 60-day retest window after a failure does not extend. However, you can retest multiple times within that 60 days at no charge. If you cannot complete repairs in time, you will need to wait until repairs are done and then retest, even if it is after the 60-day window — at that point you will pay for a new inspection.