What ADEQ emissions testing stations are and where to find one
ADEQ stands for Arizona Department of Environmental Quality. ADEQ runs the state's vehicle emissions testing program and maintains a list of authorized testing stations where you can have your vehicle inspected. These are private businesses — repair shops, tire shops, and dedicated testing centers — that have been certified by ADEQ to perform the test.
You can find an ADEQ-authorized station by visiting the ADEQ website and using their station locator tool. You enter your zip code or city, and the tool shows you nearby stations, their addresses, phone numbers, and hours. Not every repair shop in Arizona is authorized; only those certified by ADEQ appear in this list. Calling ahead to confirm hours and ask about wait times is a good idea, especially during peak testing periods.
Testing stations are concentrated in the Phoenix and Tucson areas, where emissions testing is required. If you live in a rural county where testing is not required, you will not find an ADEQ station nearby — and you will not need one.
Key Takeaways
- ADEQ-authorized testing stations are private businesses certified by Arizona's environmental agency to perform emissions tests.
- The ADEQ website has a station locator tool where you search by zip code to find nearby testing centers, their hours, and phone numbers.
- You must visit an ADEQ-authorized station; testing at an unauthorized shop will not satisfy your vehicle registration requirement.
- Testing stations are located only in counties where Arizona requires emissions testing, primarily the Phoenix and Tucson metropolitan areas.
- Stations typically charge between $20 and $40 for a test, though the exact fee varies by location.
What to bring and how the test works
Bring your vehicle registration and a valid photo ID. The technician will need to confirm the vehicle is registered to you and that the test is being done on the correct vehicle. Have your vehicle's VIN (vehicle identification number) ready as well — it is on your registration and on the dashboard.
The test itself takes 10 to 30 minutes. The technician will connect a probe to your vehicle's tailpipe and measure the emissions coming out. For newer vehicles with an onboard diagnostic system, the technician may plug a scanner into your vehicle's diagnostic port instead. You will usually wait in the station while the test runs. Once it is complete, you receive a printed result when ready.
If your vehicle passes, the station sends the result electronically to ADEQ, and you are done. If it fails, you receive a detailed report showing which emissions are too high. You then have 30 days to repair the vehicle and return for a retest at the same station or a different ADEQ station.
When you need to test and how often
Arizona requires emissions testing for vehicles registered in Maricopa County (Phoenix area) and Pima County (Tucson area). If you register a vehicle in either county, you must pass an emissions test before you can complete registration or renew it.
New vehicles are exempt from testing for their first four model years. After that, every vehicle must be tested every two years as part of the registration renewal process. Your registration renewal notice will tell you whether a test is required. If you move to a county that does not require testing, you no longer need to test.
Some vehicles are exempt even after four years: electric vehicles, vehicles that are model year 2025 or newer, and vehicles that weigh more than 14,000 pounds. Check your renewal notice or call ADEQ to confirm whether your specific vehicle is exempt.
What happens if your vehicle fails the test
A failed test means your vehicle's emissions are above the state limit for one or more pollutants. You will receive a report listing which emissions failed. Common reasons include a faulty oxygen sensor, a malfunctioning catalytic converter, or a check engine light that is on.
You have 30 days from the test date to have the vehicle repaired and retested. You can return to the same station or go to a different ADEQ-authorized station for the retest. The retest fee is separate from the original test fee. If you repair the vehicle yourself or at an independent shop, bring it back to any ADEQ station for the retest.
If you cannot repair the vehicle within 30 days, you can request a waiver from ADEQ. A waiver allows you to register the vehicle without passing the test if you have made a good-faith repair attempt and the repair cost exceeds a certain amount (this threshold varies by year and vehicle type). Contact ADEQ directly to request a waiver; the testing station cannot issue one.
Costs and what affects the test fee
Testing fees range from about $20 to $40 depending on the station and your vehicle type. Diesel vehicles and vehicles with special equipment may cost more to test. The fee is set by the individual station, not by ADEQ, so calling ahead to ask the price is reasonable.
If you fail and need a retest, you pay the fee again. Some stations offer a discount on retests or bundle the initial test and retest into one price, so ask when you call. There is no state-set retest fee; it depends on the station.
If you need a waiver because your vehicle cannot be repaired in time or the repair is too expensive, there is no fee for requesting one from ADEQ. The waiver process is free.
How to use the ADEQ station locator online
Go to the ADEQ website and look for the vehicle emissions testing section. You will find a link to the station locator tool. Enter your zip code or city name, and the tool displays all authorized stations within a certain radius, usually sorted by distance.
Each station listing shows the business name, street address, phone number, and hours of operation. Some listings include whether the station tests diesel vehicles or has any special services. Click on a station name to see more details or get directions.
If the locator shows no stations near you, you are likely in a county where testing is not required. If you are in Maricopa or Pima County and see no results, try a broader search or call ADEQ directly at the number on their website to confirm whether testing is required for your vehicle.
Preparing your vehicle before you go
Your vehicle does not need to be in perfect condition to test, but a few things help. Make sure your check engine light is off if possible — if it is on, the vehicle will likely fail. If you know the light is on because of a minor issue you have already fixed, the station may still test you, but ask first.
Warm up your vehicle before you arrive. Drive it for 10 to 15 minutes so the engine reaches normal operating temperature. A cold engine can produce higher emissions readings and cause a false failure. Avoid revving the engine or driving hard right before the test.
Make sure your gas cap is tight and not damaged. A loose or broken cap can trigger a check engine light and cause a test failure. If your cap is cracked or missing, replace it before testing — a new cap costs $5 to $15.
Frequently Asked Questions
Can I test my vehicle at any repair shop, or does it have to be an ADEQ station?
It must be an ADEQ-authorized station. Only tests performed at certified stations are reported to the state and count toward your registration requirement. Testing at an unauthorized shop will not satisfy the requirement, even if the shop has testing equipment.
What if I fail the test and cannot afford to repair my vehicle?
You can request a waiver from ADEQ if the repair cost exceeds a threshold set by the state. The waiver allows you to register the vehicle without passing the test. Contact ADEQ directly to learn the current cost threshold and start the waiver process — the testing station cannot issue a waiver.
How long does the test take, and do I have to wait?
The test itself takes 10 to 30 minutes. Most stations ask you to wait while they run it, though some may let you leave and return. Call the station ahead of time to ask their policy. Bring your phone or a book in case there is a wait.
What if I move out of state or to a county that does not require testing?
You no longer need to test. Emissions testing is required only in Maricopa and Pima counties in Arizona. If you register your vehicle in a different county or state, that jurisdiction's rules explore instead.
Can I test a vehicle that is not registered to me?
No. You must bring a valid photo ID and the vehicle registration showing you as the owner or registered keeper. The station will not test a vehicle registered to someone else.