Where to Find an Emissions Testing Center in Colorado

Colorado emissions testing centers are privately owned repair shops and service stations that have been certified by the state to perform emissions tests. You cannot test at the Colorado Department of Transportation (CDOT) or any state office — you must go to a private, certified facility. The state maintains a searchable list of all approved centers on the Colorado Department of Public Health and Environment website under the "Find a Test Center" tool.

To locate a center near you, visit the CDPHE Air Pollution Control Division website and enter your county or ZIP code. The search returns the facility name, address, phone number, and hours. Most centers are conventional auto repair shops that added emissions testing as a service, so you may recognize chains like Firestone or Midas alongside independent mechanics. Call ahead before you go — not all centers test every vehicle type, and some have limited hours or require appointments during busy seasons.

If you cannot find a center online or need help, call your county's air quality office directly. They can tell you which facilities are currently accepting tests and whether any have a backlog. During peak testing periods (typically before the registration important date in late summer), some centers fill up weeks in advance.

Key Takeaways

  • Colorado emissions testing is performed only at privately certified repair shops and service stations, never at state offices.
  • The CDPHE website has a searchable tool to find approved centers by county or ZIP code, including hours and phone numbers.
  • You need a valid vehicle registration, proof of ownership, and the vehicle's VIN before you arrive at the test center.
  • Most tests take 30 minutes to an hour, and you receive a pass or fail result on the same day.
  • If your vehicle fails, the test center can recommend repairs, but you must return to any certified center (not necessarily the same one) for a retest.

What to Bring and How the Test Works

Bring your vehicle registration, proof of ownership (title or lease agreement), and your vehicle's VIN before you arrive. The technician will verify that your vehicle is registered in Colorado and that the test is due. Colorado requires emissions testing every two years for most vehicles, though some counties have annual testing. The technician will confirm whether your vehicle is due based on your registration renewal date.

The actual test takes 30 minutes to an hour. The technician connects a probe to your vehicle's tailpipe and measures emissions of nitrogen oxides, particulate matter, and other pollutants. For newer vehicles (typically 1996 and later), the test also includes a computer scan of your vehicle's onboard diagnostic system to check for fault codes. The vehicle must be warmed up before testing begins, so arrive with a few miles of highway driving already done if possible.

You will receive your result the same day. A pass means your vehicle meets Colorado's emissions standards and you can renew your registration. A fail means your vehicle exceeded limits and you have 60 days to make repairs and retest. The test center will provide a written report showing which emissions exceeded the standard and may recommend repairs, though you are not required to use their repair services.

Costs and Payment Methods

Emissions testing fees vary by facility but typically range from $20 to $35 per test. Some centers charge a flat rate; others charge differently for diesel vehicles or older vehicles that require more extensive testing. Call the center before you go to confirm the exact price. Most centers accept cash, credit cards, and debit cards, though it is worth asking when you call.

If your vehicle fails the first test, you pay for the retest separately. The retest fee is usually the same as the initial test fee. Some centers offer a discount if you return within a certain timeframe (for example, within 30 days), so ask about that when you call with your test result.

What Happens if Your Vehicle Fails

A failed test does not prevent you from driving your vehicle, but you cannot renew your registration until you pass. You have 60 days from the test date to make repairs and retest. During those 60 days, you can continue driving on your current registration, but you cannot renew it online or at the DMV until you have a passing test result.

After you fail, you can take your vehicle to any repair shop — not necessarily the testing center — to diagnose and fix the problem. Common failures involve a faulty oxygen sensor, a loose gas cap, or a malfunctioning catalytic converter. If repairs are expensive, some counties offer repair information programs, though funding and may be able to access vary. Contact your county air quality office to ask whether your county has a repair information program.

Once repairs are complete, return to any certified emissions testing center for a retest. You do not have to return to the same center where you failed. Bring the same documents (registration, proof of ownership, VIN) and the same fee. If you pass the retest, you can renew your registration when ready.

Special Cases: Diesel Vehicles and Out-of-State Vehicles

Diesel vehicles follow the same testing schedule as gasoline vehicles but use different emissions standards. Not all testing centers are equipped to test diesel vehicles, so confirm when you call. Diesel tests typically cost the same as gasoline tests but may take slightly longer because the equipment differs.

If you recently moved to Colorado or purchased a vehicle out of state, you must have an emissions test before you can register it in Colorado. The test must be performed at a Colorado-certified center using your out-of-state vehicle's VIN and current out-of-state registration. Once you pass, you can complete your Colorado registration at any DMV office or online.

Scheduling and Timing During Peak Seasons

Colorado's registration renewal important date is typically in late summer, which means July and August are the busiest months for emissions testing. If you wait until August to test, you may face long waits or be unable to find an appointment. Testing centers often book up two to three weeks in advance during peak season.

To avoid delays, schedule your test as soon as your registration renewal notice arrives (usually 60 days before your renewal date). Many centers allow you to book online or by phone. If you cannot find an appointment at your preferred center, call a few others in your area — availability varies by location and day of the week.

If you miss the important date and your registration expires before you pass an emissions test, you cannot legally drive your vehicle. However, you can still test and renew your registration after the important date; there is no penalty for testing late, only for driving with an expired registration.

Frequently Asked Questions

Can I test my vehicle at any certified center, or do I have to go to a specific one?

You can test at any certified center in Colorado. You do not have to use the center closest to you or the one where you had your last test. If your preferred center is booked, call another one. If you fail and need a retest, you can go to a different center than the one where you failed.

What if my vehicle is too old to test?

Colorado does not test vehicles older than a certain model year, which varies by county. Most counties exempt vehicles 25 years old or older. Call your county air quality office or the testing center to confirm whether your vehicle is exempt based on its age and your county.

Do I need an appointment, or can I just walk in?

Some centers accept walk-ins, but many require appointments, especially during busy seasons. Call ahead to ask. If you walk in without an appointment, you may wait several hours or be turned away if the center is fully booked.

What if I fail the test twice?

You can retest as many times as needed within the 60-day window. Each retest costs the same fee. If you cannot pass within 60 days, your registration expires and you must renew it before you can legally drive. You can continue testing after the important date, but you cannot drive until you pass and renew.

Can I test my vehicle before my registration is due?

Yes. You can test up to 60 days before your registration renewal date. The test result is valid for your entire registration period, so testing early does not shorten the time until your next test is due.