Arizona requires emissions testing in two counties, and the rules depend on where you live and what you drive

Arizona does not require emissions testing statewide. Only Maricopa County (which includes Phoenix) and Pima County (which includes Tucson) have active emissions testing programs. If you live elsewhere in Arizona, you do not need to test your vehicle for emissions to renew your registration.

In the two counties that do require it, the test itself is straightforward: a technician plugs a diagnostic scanner into your vehicle's onboard computer and checks whether your emissions systems are working within state limits. The test takes about 10 minutes and costs around $20 to $30, though the exact fee varies by testing station.

Your vehicle's model year, fuel type, and whether it has a diesel engine all affect whether you must test at all. Some vehicles are exempt entirely. Others test every year. A few test every other year. Understanding which category your vehicle falls into before you head to a testing station saves a trip.

Key Takeaways

  • Only Maricopa and Pima counties in Arizona require emissions testing; all other counties do not.
  • Vehicles from model year 1975 and earlier, electric vehicles, and some motorcycles are exempt from testing in both counties.
  • Most gasoline vehicles in Maricopa and Pima counties must test every year; some newer vehicles test every other year depending on the county's rules.
  • You can find a testing station through the Arizona Department of Environmental Quality website or by searching for "emissions testing" in your county.
  • A failed test does not automatically mean you cannot renew your registration; you have options to repair and retest or request a waiver.

Maricopa County emissions testing requirements

Maricopa County requires emissions testing for most vehicles registered there. The county's program covers gasoline vehicles, diesel vehicles, and motorcycles, though not all of them test on the same schedule.

Gasoline-powered vehicles from model year 1981 onward must test every year. Diesel vehicles from model year 1997 onward must also test every year. Motorcycles registered in Maricopa County are exempt from testing entirely. Vehicles from model year 1975 and earlier do not test, regardless of fuel type.

Electric vehicles and vehicles powered entirely by natural gas are exempt. Vehicles with a gross vehicle weight rating above 14,000 pounds are also exempt, as are vehicles registered as historical or special interest vehicles.

Maricopa County does not use a biennial (every-other-year) testing schedule. Every vehicle that is subject to testing must test annually when you renew your registration.

Pima County emissions testing requirements

Pima County's program is similar to Maricopa's but with one significant difference: some newer vehicles test every other year instead of every year.

Gasoline vehicles from model year 1981 onward must test. Diesel vehicles from model year 1997 onward must test. The key distinction is that vehicles from model year 1996 and newer test every two years, while older vehicles test every year. Motorcycles are exempt. Vehicles from model year 1975 and earlier do not test.

Electric vehicles, natural gas vehicles, and vehicles with a gross vehicle weight rating above 14,000 pounds are exempt in Pima County as well. Historical and special interest vehicles are also exempt.

If you own a vehicle that tests every other year, you still renew your registration annually, but you only submit to emissions testing in the years when it is due. The testing station and the Arizona Department of Environmental Quality track which year your vehicle is scheduled to test.

What happens if your vehicle fails the emissions test

A failed test does not automatically prevent you from renewing your registration. Arizona law allows you several paths forward.

The most direct option is to repair the emissions system and retest. You can retest at any testing station in your county. There is no additional fee for a retest if you fail the first time. Many repairs are straightforward—a loose gas cap, a faulty oxygen sensor, or a malfunctioning catalytic converter—and once fixed, the vehicle typically passes on the second attempt.

If repair costs are high or the vehicle is older, you may be able to request a waiver from the Arizona Department of Environmental Quality. A waiver allows you to renew your registration without passing the test, though the criteria are strict. You generally must show that the cost of repair exceeds a certain percentage of the vehicle's value, or that you have already made a good-faith repair attempt that did not resolve the problem. Waivers are not automatic; you must request one and provide documentation.

If you do not repair the vehicle and do not obtain a waiver, you cannot renew your registration in that county. This means you cannot legally drive the vehicle on public roads.

How to find a testing station and schedule a test

The Arizona Department of Environmental Quality maintains a list of authorized emissions testing stations on its website. You can search by county and city to find stations near you. Most stations are operated by repair shops, tire retailers, or dedicated testing facilities.

Many testing stations accept walk-ins, but some require appointments, especially during peak renewal periods (typically late in the month or late in the year). Calling ahead to confirm hours and whether an appointment is needed saves time.

When you arrive, bring your vehicle registration and a valid photo ID. The technician will connect a diagnostic scanner to your vehicle's onboard diagnostic port, usually located under the steering wheel or dashboard. The test takes about 10 minutes. You will receive a printed report showing whether your vehicle passed or failed, along with any diagnostic trouble codes if it failed.

If you pass, the testing station submits the results electronically to the Arizona Department of Environmental Quality and to the Motor Vehicle Division. You can then renew your registration online, by mail, or in person at a Motor Vehicle Division office.

Vehicles exempt from Arizona emissions testing

Several categories of vehicles do not need to test in either Maricopa or Pima County, even if they are registered there.

All vehicles from model year 1975 and earlier are exempt. Electric vehicles and vehicles powered entirely by compressed natural gas are exempt. Motorcycles are exempt in both counties. Vehicles with a gross vehicle weight rating above 14,000 pounds are exempt. Vehicles registered as historical, classic, or special interest vehicles are also exempt, though you must have the appropriate registration designation.

Hybrid vehicles that have a gasoline engine are not exempt; they must test like any other gasoline vehicle. The exemption applies only to vehicles with no internal combustion engine at all.

If you believe your vehicle should be exempt but are unsure, contact the Arizona Department of Environmental Quality or your county's Motor Vehicle Division office. They can confirm your vehicle's status based on its model year, fuel type, and registration class.

Frequently Asked Questions

Do I need emissions testing if I just moved to Arizona from another state?

If you move to Maricopa or Pima County, you must register your vehicle in Arizona within 30 days. When you do, you will need to pass an emissions test before your registration is issued, unless your vehicle is exempt. If you move to a county that does not require testing, you do not need to test.

What if I buy a used car in Arizona—do I test before or after I register it?

You must test before you register it in Maricopa or Pima County. The test is part of the registration process. Some dealers handle this for you; others require you to test on your own before you complete the purchase and transfer.

Can I renew my registration online if I have not tested yet?

No. The Motor Vehicle Division will not issue a registration renewal until an emissions test result has been submitted. You must test first, then renew. If you attempt to renew online without a test result on file, the system will reject the request.

How long does an emissions test result stay valid?

A passing test result is valid for one year in Maricopa County and for two years in Pima County (for vehicles on the biennial schedule). Once that period expires, you must test again to renew your registration.

What if the testing station says my vehicle cannot be tested because of a mechanical problem?

Some vehicles cannot complete the test if the check engine light is on, if the onboard diagnostic system is not responding, or if the vehicle has other mechanical issues that prevent the scanner from communicating. The technician will provide a report explaining why the test could not be completed. You will need to repair the issue and return for another test attempt.