Finding an emissions testing station near you
Colorado emissions tests happen at Authorized Emissions Test Providers — private repair shops and service stations that the state has certified to run the test equipment. You cannot test at the DMV, a county office, or a state facility. Instead, you find a provider in your area, call or visit to schedule, and bring your vehicle on the appointment day.
The Colorado Department of Revenue maintains a searchable list of all active providers on its website. You can filter by county or city, and each listing shows the shop's address, phone number, and hours. Most providers can fit you in within a few days, though busy shops near the end of testing season (typically October and November) may have longer waits.
You do not need to go to the shop where you bought your car or where you normally get service. Any certified provider can test any vehicle, regardless of where it was purchased or serviced. Choose based on location, hours, and how quickly they can see you.
Key Takeaways
- Emissions tests in Colorado are performed only at private Authorized Emissions Test Providers, not at government offices.
- The Colorado Department of Revenue publishes a searchable list of all certified providers, organized by county and city.
- You can use any certified provider in the state; you are not required to test at a specific shop or location.
- Most providers offer same-week or next-week appointments, but waits lengthen in October and November.
- Call ahead to confirm hours and ask whether you need an appointment or can walk in.
How to search the official provider list
Go to the Colorado Department of Revenue's Air Quality Control Commission website and look for the "Find an Emissions Test Provider" tool. Enter your county or city name, and the system returns all active providers in that area with their contact information and business hours.
The list updates regularly as providers open, close, or change their status. If a shop you used before no longer appears, it means it is no longer certified. Do not call a shop that is not on the current list — it cannot legally perform emissions tests in Colorado.
Print or save the list before you call, so you have multiple options. Some shops fill up quickly during peak season, and having backup choices means you can get tested sooner rather than waiting weeks.
What to bring and what to expect
Bring your vehicle registration and proof of insurance. The provider will ask for your vehicle identification number (VIN) and current mileage. Have your keys ready so the technician can start the engine and connect the test equipment.
The test itself takes 10 to 20 minutes. The technician plugs a diagnostic device into your vehicle's onboard computer port (usually under the steering wheel or dashboard) and runs a series of checks on your emissions system. You will sit in the waiting area while this happens. Once the test is complete, you receive your results when ready — either a pass or a fail with specific details about what did not meet standards.
If you pass, the provider prints your certificate and submits it electronically to the state. You can then renew your registration. If you fail, the certificate shows which emissions components or readings were out of range, which helps a mechanic diagnose what needs repair.
Testing requirements by county and vehicle age
Colorado requires emissions testing in the Denver metro area and several surrounding counties. The list includes Denver, Adams, Arapahoe, Boulder, Douglas, El Paso, Jefferson, Larimer, and Weld counties. If you live outside these counties, you do not need an emissions test — you only need a safety inspection to renew your registration.
Within the testing counties, most vehicles model year 1982 and newer must be tested every two years. Vehicles model year 1981 and older are exempt. Some newer vehicles may be exempt for their first few years of registration, depending on when they were first registered in Colorado.
Check your registration renewal notice to confirm whether your vehicle is due for testing. The notice will say "emissions test required" or will not mention it. If you are unsure, call your local county assessor's office or the provider you plan to visit — they can confirm your vehicle's testing status.
Cost and payment methods
Emissions test fees vary by provider but typically range from $25 to $35. Some shops charge a flat rate; others charge slightly more if your vehicle fails and you return for a retest. Call ahead to ask the exact fee and whether the provider accepts cash, card, or both.
The test fee is separate from any repairs you may need if you fail. If your vehicle does not pass, you will need to take it to a mechanic for diagnosis and repair, then return to the same or a different provider for a retest. Retests are usually the same price as the initial test.
What happens if your vehicle fails the test
A failed test means your vehicle's emissions system is not meeting Colorado standards. The test report will identify which specific system or reading failed — for example, nitrogen oxides (NOx) too high, or the onboard diagnostic system showing a fault code.
Take the failed test report to a mechanic who works on emissions systems. Common repairs include replacing a faulty oxygen sensor, fixing a vacuum leak, or addressing a check engine light. Once repairs are done, you can schedule a retest at any certified provider. You do not have to return to the same shop that tested you initially.
Colorado gives you until your registration expires to pass a retest. If you cannot get your vehicle to pass before that date, your registration will not renew. Some providers and repair shops offer a "test and repair" service where they can diagnose and fix emissions issues in one visit, though this is not required — you can use separate shops for testing and repair.
Scheduling and timing tips
Call or visit the provider's website to schedule an appointment. Many shops now offer online booking. Bring your vehicle on the scheduled day with a full or near-full fuel tank — some providers require this, and it ensures the test runs smoothly.
Avoid scheduling during October and November if possible. These are the busiest months for emissions testing in Colorado, and waits can stretch to several weeks. If your registration expires in November or December, schedule your test in August or September to avoid the rush.
If you are moving out of Colorado or selling your vehicle, you may not need a new emissions test. Check with the provider or your county assessor about whether your situation qualifies for an exemption.
Frequently Asked Questions
Can I test my vehicle at any provider, or do I have to go to a specific one?
You can use any Authorized Emissions Test Provider on the state's current list. You are not assigned to a particular shop or location. Choose based on convenience, hours, and availability.
What if I cannot find a provider in my area on the list?
Check the list again and expand your search to nearby cities or counties. If your area genuinely has no active providers, contact your county assessor's office — they can direct you to the nearest certified shop or tell you whether your vehicle is exempt from testing.
Do I need an appointment, or can I walk in?
Most providers require an appointment, especially during busy seasons. Call ahead to confirm. Some shops accept walk-ins during slow periods, but do not assume — you may wait hours or be turned away.
How long does the test take from start to finish?
The actual test takes 10 to 20 minutes. Add time for check-in, paperwork, and waiting. Plan for 30 to 45 minutes total. Bring your registration and insurance card to speed up the process.
Can I retest at a different provider than the one that tested me initially?
Yes. If you fail and get repairs done, you can take your vehicle to any other certified provider for the retest. You do not have to return to the original shop.