If your vehicle is registered in Williamson County, you still need a passing emissions test every year before you can renew your registration. That applies whether you live in Round Rock, Cedar Park, Georgetown, Leander, Hutto, Taylor, or one of the north Austin neighborhoods that sit on the Williamson side of the county line. Safety inspections ended in 2025, but the emissions requirement did not go anywhere. Here is who needs the test, where you can get it done, and how to pass on the first visit.
Yes, Williamson County Still Requires Emissions Testing
Texas eliminated the annual safety inspection for non-commercial vehicles on January 1, 2025 under House Bill 3297. No more checks of your lights, horn, or wipers. That change caused a lot of confusion, and we still meet drivers who believe inspections are gone entirely.
They are not. Emissions testing is still required in 17 Texas counties, and Williamson County is one of them, along with Travis County next door. If your gasoline vehicle is between 2 and 24 model years old and registered in Williamson County, it needs a passing emissions test each year before registration renewal. For the full statewide picture, see our 2026 Texas emissions test guide.
Which Vehicles Need the Test
Your vehicle needs an annual emissions test if all three of these apply:
- It is registered in Williamson County (or another emissions county such as Travis)
- It runs on gasoline
- It is between 2 and 24 model years old
Electric vehicles, diesel vehicles, and motorcycles are exempt, along with vehicles newer than 2 model years or older than 24.
Where Williamson County Drivers Can Get Tested
Here is the part many drivers do not realize: you are not required to test inside Williamson County. Travis and Williamson counties are part of the same Austin-area emissions program, so any certified emissions station in the area can test your vehicle, regardless of which of the two counties you live in.
That matters if you live in Round Rock, Wells Branch, or anywhere along the I-35 corridor, because the county line runs right through the middle of the metro. Vick’s Expertune sits on West Howard Lane just off I-35, a few minutes south of the Williamson County line. We are a state-certified emissions testing facility, and we test vehicles registered in both Travis and Williamson County.
The test itself is an OBD-II computer scan, not a tailpipe check, and typically takes 15 to 20 minutes. The equipment verifies that your check engine light is off, that no active trouble codes are stored, and that your vehicle’s readiness monitors are set.
Austin Address, Williamson County: Which Rules Apply?
Plenty of homes with an Austin or Cedar Park mailing address are actually inside Williamson County. If you are not sure which county your vehicle is registered in, check your registration renewal notice; the county is printed on it.
The good news is that for Austin-metro drivers, the answer is the same either way. Both Travis and Williamson counties require the annual emissions test, and both are served by the same network of certified stations. Wherever the line falls relative to your driveway, the requirement and the process do not change.
What It Costs
| Item | Cost |
|---|---|
| Emissions test fee | $11.50 at Vick’s (varies by station) |
| State inspection replacement fee (at registration renewal) | $7.50 |
| Retest after failure (within 15 days) | Free |
If Your Vehicle Fails
The most common reason for failure, by far, is a check engine light that is on. Even if the car drives perfectly, an illuminated light is an automatic fail until the underlying problem is fixed. Clearing the codes with a scan tool will not help; it resets the readiness monitors, and the test cannot be completed until those monitors are set again, which takes 50 to 100 miles of varied driving.
If you fail, you will get a Vehicle Inspection Report listing the reason. You then have 15 days to make repairs and return for a free retest. A professional engine diagnostic scan pinpoints the actual cause so you fix the right thing the first time, whether that is a $15 gas cap or a failing oxygen sensor. Our guide on passing the Texas emissions test on the first try covers the most common failure causes in detail.
Time It Right
You can complete the emissions test up to 90 days before your registration expires. If your check engine light is on, or your battery was recently replaced or disconnected, get tested early in that window. Failing with two months of cushion is an inconvenience. Failing the week your registration expires is a much bigger problem, because repairs and the 50 to 100 miles of monitor-resetting driving both take time.
Frequently Asked Questions
Does Williamson County require emissions testing in 2026?
Yes. Safety inspections ended in January 2025, but Williamson County still requires an annual emissions test for gasoline vehicles 2 to 24 model years old before registration renewal.
Where can I get an emissions test if I live in Round Rock, Cedar Park, or Georgetown?
At any certified emissions station in the Austin program area. Travis and Williamson counties share the same program, so many Williamson County drivers test at North Austin shops near the county line, including Vick’s Expertune on West Howard Lane just off I-35.
How much does the test cost?
The emissions test is $11.50 at Vick’s; prices vary by station. A $7.50 state inspection replacement fee also applies when you renew your registration.
My address says Austin but my county is Williamson. Which rules apply?
The requirement follows the county where your vehicle is registered, not your mailing address. Both Travis and Williamson require the test, so for Austin-metro drivers the process is the same either way.
Do I still need a safety inspection?
No. The annual safety inspection for non-commercial vehicles was eliminated on January 1, 2025. The emissions test is the only inspection Williamson County drivers still need.
What happens if my car fails?
You get a Vehicle Inspection Report listing the reason, and you have 15 days to make repairs and return to the same station for a free retest. A check engine light that is on is the most common cause of failure.
When should I get tested?
Up to 90 days before your registration expires. Testing early leaves time to diagnose and repair any problem, and to use the free 15-day retest, before your deadline.