What Aurora Requires and When

Aurora, Colorado requires emissions testing for most vehicles registered in the city, with the specific rules depending on the vehicle's model year and fuel type. Gasoline-powered vehicles from 1981 onward must pass an emissions test every two years, while diesel vehicles from 1997 onward face the same requirement. Vehicles registered in Aurora but garaged outside the city still need to test in Aurora if they are subject to the requirement.

The test itself measures tailpipe emissions — carbon monoxide, nitrogen oxides, and particulate matter — against Colorado state standards. A vehicle either passes or fails; there is no partial credit. If your vehicle fails, you have 60 days to repair it and retest at no additional fee, though you cannot renew your registration until it passes.

Vehicles manufactured in the current year and the two years prior are exempt from testing. So a vehicle registered in 2024 does not need to test until 2026. Hybrid and electric vehicles are also exempt, as are vehicles with a gross vehicle weight rating above 14,000 pounds.

Key Takeaways

  • Aurora requires emissions testing every two years for gasoline vehicles from 1981 onward and diesel vehicles from 1997 onward.
  • The test measures tailpipe emissions against Colorado state standards, and you cannot renew your registration without a passing result.
  • If you fail, you have 60 days to repair and retest for free at the same testing station.
  • You can find Aurora-approved testing stations through the Colorado Department of Public Health and Environment website or by calling the Aurora emissions hotline.
  • Vehicles from the current year and two prior model years, plus hybrids and electric vehicles, do not need to test.

Where to Get Tested in Aurora

Aurora has multiple emissions testing stations, all certified by the Colorado Department of Public Health and Environment. You can locate them by visiting the state's official emissions testing locator or by calling the Aurora City Clerk's Office at 720-913-3000. The locator shows each station's hours, address, and whether they accept walk-ins or require appointments.

Testing typically takes 10 to 15 minutes once you are in the bay. Bring your vehicle registration, proof of insurance, and a valid ID. Some stations charge a flat fee — usually between $20 and $30 — though the exact amount varies by station. A few stations offer discounts for seniors or low-income residents, so ask when you call.

If a station is busy, you can test at any other Aurora-approved station. The result is recorded in the state system when ready, so your registration can be renewed the same day if you pass.

What Happens If You Fail

A failure means your vehicle's emissions exceed Colorado limits for one or more pollutants. The test report will specify which pollutants are out of range — typically high carbon monoxide, high nitrogen oxides, or visible smoke. This information tells a mechanic where to focus repairs.

You have 60 days from the test date to repair your vehicle and retest. The retest is free at the same station, and you do not need to pay the testing fee again. Common repairs include replacing a faulty oxygen sensor, fixing a vacuum leak, or addressing a malfunctioning catalytic converter. If repairs are expensive, some nonprofits and local programs offer low-cost repair information; ask your mechanic or contact the Aurora Public Health Department.

If you do not retest within 60 days, your registration cannot be renewed. If your registration expires before you pass, you cannot legally drive the vehicle in Aurora until you test and pass.

Timing and Registration Renewal

Your emissions test is valid for two years from the test date. You must pass before you renew your vehicle registration. If your registration expires in June, you should test by June to avoid a lapse. Many people test in the month before their registration expires to avoid the rush.

The state system shares the test result with the Colorado Department of Motor Vehicles automatically, so you do not need to bring a paper copy to renew. You can renew online, by mail, or in person at any DMV office or authorized county clerk's office. If you renew online and your emissions test is not yet recorded, the system will reject the renewal; wait a day and try again, or call the testing station to confirm the result was submitted.

Special Cases and Exemptions

Vehicles with a gross vehicle weight rating above 14,000 pounds — typically large trucks and commercial vehicles — are exempt from emissions testing in Aurora. Vehicles registered as historic or collector vehicles may also be exempt if they meet state criteria; contact the Aurora City Clerk's Office to confirm your vehicle's status.

If you own a vehicle that fails repeatedly despite repairs, you may be may be able to access for a hardship exemption or a repair information program. The Colorado Department of Public Health and Environment administers a Repair information Program for low-income vehicle owners; may be able to access is based on household income and the cost of repairs. Contact the Aurora Public Health Department for details and a referral.

Vehicles registered outside Aurora but garaged in the city are still subject to Aurora's testing requirement if they meet the age and fuel-type criteria. The testing location must be in Aurora, not in the vehicle's home county.

Understanding Your Test Results

A passing result means your vehicle met Colorado's emissions standards for all measured pollutants. The test report shows the actual readings for carbon monoxide, nitrogen oxides, and other pollutants, plus the state limits. You do not need to do anything with this report unless you fail; a passing result is recorded in the state system and linked to your registration automatically.

A failing result lists which pollutants exceeded the limit and by how much. For example, a report might show carbon monoxide at 150 parts per million when the limit is 100. This tells a mechanic that the engine is running too rich — burning too much fuel — which could indicate a faulty oxygen sensor, a clogged air filter, or a malfunctioning fuel injector. The test report itself does not diagnose the problem, but it narrows the search.

If you dispute a test result, you can request a retest at a different station within 30 days. The second test is also free if you fail again. If you pass the second test, the first failure is disregarded for registration purposes.

Frequently Asked Questions

Can I test before my registration expires?

Yes. You can test up to 60 days before your registration expires. The result is valid for two years, so testing early gives you a buffer. Many people test two to three months before expiration to avoid the last-minute rush.

What if I just moved to Aurora from another county?

If your vehicle is subject to testing and you register it in Aurora, you must pass an emissions test before you can renew or transfer the registration. If your vehicle was tested in another Colorado county within the past two years, that result may be accepted; contact the Aurora City Clerk's Office to confirm.

Do I need an appointment or can I just show up?

It depends on the station. Some accept walk-ins during posted hours; others require appointments. The Colorado emissions testing locator shows which stations take appointments and which do not. Calling ahead is always safe and usually gets you in faster.

What if my vehicle is too old to pass?

If your vehicle is very old or has high mileage, repairs may be expensive or impossible. You may be may be able to access for a hardship exemption or repair information through the Colorado Department of Public Health and Environment. Contact the Aurora Public Health Department to discuss your options; some programs help with the cost of repairs or replacement.

How long does the whole process take?

Testing itself takes 10 to 15 minutes. If you pass, you are done. If you fail, repairs can take anywhere from a few days to a few weeks depending on the problem and your mechanic's schedule. You then retest, which again takes 10 to 15 minutes. Plan for at least a week from failure to retest if repairs are straightforward.