What Arizona emissions testing requires

Arizona requires emissions testing for most vehicles registered in Maricopa and Pima counties — the state's two most populated areas. If you live outside those counties, you do not need to test. The test measures what comes out of your tailpipe: hydrocarbons, nitrogen oxides, carbon monoxide, and particulate matter. A vehicle passes if those levels stay below state limits.

You must test every two years, and the test is valid for 60 days from the date you take it. Your registration renewal notice will tell you whether your vehicle needs testing. If you buy a used car in Arizona, you typically need a test before you can register it, unless the previous owner's test is still valid and transfers to you.

Diesel vehicles, motorcycles, and vehicles model year 1975 and older are exempt. Vehicles registered as classic cars or antiques also do not test. If your vehicle is newer than the current model year minus 3 years, it may be exempt depending on when you first registered it in Arizona.

Key Takeaways

  • Arizona emissions testing is required only in Maricopa and Pima counties, and you must test every two years before your registration expires.
  • You can test at any Arizona Department of Environmental Quality (ADEQ) testing station or at a private emissions testing facility — both charge the same state-set fee.
  • Bring your vehicle registration and a valid photo ID; the test takes about 10 minutes and you receive results the same day.
  • If your vehicle fails, you have 60 days to repair it and retest at no additional charge, or you can request a waiver if repairs cost more than a set amount.

Where to find a testing station in your area

ADEQ operates testing stations in the Phoenix and Tucson areas. You can find the nearest station and check hours on the ADEQ website under "Emissions Testing Stations." Private testing facilities also perform the same test and are scattered throughout both counties — many are at repair shops, tire stores, or dedicated testing centers.

Both ADEQ stations and private facilities charge the same fee, which the state sets. The fee does not change based on where you test. Some private facilities may charge a small additional fee if they also perform repairs, but the emissions test itself costs the same everywhere.

You do not need an appointment at most ADEQ stations, though some private facilities do take them. Calling ahead can save you a wait, especially during peak times like the month before registration expires.

What to bring and what happens during the test

Bring your vehicle registration and a valid photo ID. The technician will ask for your vehicle identification number (VIN) and odometer reading. The test itself takes about 10 minutes. Your vehicle is connected to a machine that reads emissions from the tailpipe while the engine runs at different speeds.

You stay in the waiting area during the test. The technician will tell you whether you passed or failed before you leave. If you pass, you receive a printed certificate or a digital record that the testing station sends to the Motor Vehicle Division. You do not have to do anything else — your registration will renew.

If you fail, the certificate will list which pollutants exceeded the limit. You can take this information to a mechanic to help diagnose the problem. The testing station will also give you information about the repair information program and the waiver process.

What to do if your vehicle fails the test

You have 60 days from the test date to repair your vehicle and retest. The retest is free — you pay only if you test a third time. Many common failures come from a loose gas cap, a faulty oxygen sensor, or a clogged air filter, all relatively inexpensive fixes.

If repair costs are high, you may be able to request a repair cost waiver. Arizona allows a waiver if the cost to fix the emissions problem exceeds a certain percentage of your vehicle's value. The testing station can explain the waiver process and help you gather the information you need. If approved, you can register your vehicle without retesting.

Arizona also offers a repair information program for low-income vehicle owners. The program can help pay for emissions-related repairs. You can ask the testing station for information about this program, or contact ADEQ directly.

How emissions testing connects to vehicle registration

Your registration renewal notice will show whether your vehicle needs testing. You must test before your registration expires. If you do not test and your registration lapses, you cannot legally drive the vehicle until you register it again — and you will need a current test to do that.

When you pass the test, the testing station reports the result to the Motor Vehicle Division electronically. You do not have to submit anything yourself. Your registration will renew as long as you have paid the renewal fee and have no other holds on your account.

If you move out of Maricopa or Pima county, you no longer need to test. If you move into one of those counties, you will need to test before you can register your vehicle there.

Understanding your test results

A passing result means your vehicle's emissions are within state limits for all pollutants tested. The certificate shows the actual readings and the state limits side by side. You can keep this certificate for your records, though you do not need it for anything — the testing station files it with the state.

A failing result lists which pollutants were too high. Common failures include high nitrogen oxides (often from engine timing or fuel system problems), high hydrocarbons (usually from ignition or fuel system issues), or high carbon monoxide (often from a rich fuel mixture). The certificate may include general repair suggestions, but a mechanic will need to diagnose the specific cause.

Some vehicles fail because of a check engine light or a pending diagnostic trouble code. If your check engine light is on, have a mechanic read the code before you test — fixing that problem often resolves the emissions failure.

Frequently Asked Questions

Do I need emissions testing if I just bought a used car in Arizona?

If you buy from a dealer, they usually handle the test before you take the car. If you buy from a private seller, you need a current test (less than 60 days old) before you can register it. Ask the seller whether they have already tested the vehicle. If not, you can test it before or after you buy it — the test is tied to the vehicle, not the owner.

What if I cannot get to a testing station before my registration expires?

You can renew your registration online or by mail without the test, but your registration will be marked as conditional. You then have 30 days after renewal to test and provide proof. If you do not test within that window, your registration becomes invalid and you cannot legally drive. Plan ahead and test before your renewal date to avoid this situation.

Can I test my vehicle in a different county than where I live?

Yes. If you live in Maricopa County but are near a Pima County testing station, you can test there. The result is valid regardless of where you test, as long as you test in Arizona. The testing station will report the result to the state, and it will count toward your registration renewal.

What happens if my vehicle is too old to test?

Vehicles model year 1975 and older do not test. You can register them without an emissions certificate. If your vehicle is newer than 1975 but you believe it should be exempt, contact ADEQ or the Motor Vehicle Division to verify your vehicle's exemption status before your registration expires.

How much does the emissions test cost?

The state sets a standard fee for all emissions tests in Arizona. The fee is the same at ADEQ stations and private facilities. Check the ADEQ website or call a testing station near you for the current fee amount, as it may change year to year.