What Air Care Colorado is and who runs it

Air Care Colorado is the emissions testing program run by the Colorado Department of Public Health and Environment. It tests whether your vehicle meets the state's air quality standards. The program operates testing stations across the Denver metro area and some surrounding counties — not statewide.

Air Care Colorado is a private contractor system: the state sets the rules and standards, but private testing stations do the actual inspections. You choose which station to visit from a list of approved locations. The program has been in place since 1982 and currently tests roughly 2 million vehicles per year.

Not all of Colorado requires emissions testing. The program covers the Denver-Boulder area and parts of El Paso, Jefferson, and Weld counties — basically the Front Range corridor where air quality is monitored most closely. If you live outside these areas, you do not need an Air Care Colorado test.

Key Takeaways

  • Air Care Colorado tests vehicles in the Denver metro area and surrounding counties; check the official website to confirm your address is in a testing area.
  • You must test every two years, and your test is due in the month shown on your registration — not whenever you feel like it.
  • The test itself takes about 10 minutes and costs between $20 and $30 depending on the station.
  • You can schedule online, by phone, or walk in at most stations, though online booking often has shorter wait times.
  • If your vehicle fails, you have 60 days to fix it and retest at no extra charge before you must pay the full fee again.

When your test is due and how to find your important date

Your emissions test is due in the month printed on your vehicle registration card. That month is your test month — you can test anytime during that month, and you have until the last day to do it. If you miss your test month, your registration becomes invalid and you cannot legally drive the vehicle.

To find your test month, look at your registration card. The month and year appear in the upper right corner. For example, if your card says "06/2025," your test is due sometime in June 2025. You do not have to wait until the last week — testing early in your month is often faster because fewer people are in line.

Air Care Colorado sends reminder notices by mail about 30 days before your test month begins, but do not rely on the mail arriving. Check your registration card yourself. If you have lost your card or are unsure of the date, you can look up your vehicle on the Air Care Colorado website using your license plate number.

How to schedule and what to bring

You have three ways to schedule a test: online at the Air Care Colorado website, by phone at 1-888-242-7333, or by walking into a testing station without an appointment. Online scheduling usually has the shortest wait times and lets you pick a specific date and time. Phone scheduling takes longer but works if you prefer talking to someone.

Bring your vehicle registration card and a valid photo ID. That is all you need. The vehicle itself must be in drivable condition — if it will not start or has obvious mechanical problems, the station will not test it. You do not need to bring proof of insurance or anything else.

Most testing stations are open Monday through Friday during business hours, with some weekend hours at larger locations. The test itself takes about 10 minutes. The station will plug a probe into your vehicle's emissions port (usually under the dashboard on the driver's side) and measure what comes out of your tailpipe. You will get your result on the spot.

What happens if you pass

If your vehicle passes, you will receive a passing certificate on the spot — usually printed on a small card or receipt. You do not need to do anything with this certificate. The testing station sends the result electronically to the Colorado Department of Motor Vehicles, and your registration automatically stays valid.

You are good to drive legally for another two years. Your next test will be due in the same month, two years later. For example, if you test in June 2025, your next test is due in June 2027.

What happens if you fail

If your vehicle fails, you will get a failing report that lists which emissions standards you did not meet. Common failures include high nitrogen oxides, high particulate matter, or problems with the vehicle's emissions control system. The report will tell you which pollutants are too high.

You have 60 days from the test date to fix the problem and retest for free. You do not pay the testing fee again during this 60-day window — just bring your failing report to any Air Care Colorado station and they will retest you at no charge. If you fix the vehicle and pass the retest within 60 days, you are done.

If you do not retest within 60 days, or if you retest and fail again, you must pay the full testing fee again to test a third time. After three failed tests in a row, the vehicle is considered a gross polluter and you cannot register it in Colorado until it passes. At that point, you will need to have a mechanic diagnose and repair the emissions system — this is not something you can fix yourself in most cases.

Cost and payment methods

The test costs between $20 and $30 depending on which station you use. Air Care Colorado does not set a single price; each testing station sets its own fee within that range. Most stations charge around $25. You can call ahead or check the station's website to confirm the exact price before you go.

All stations accept cash and credit cards. Some accept checks. If you fail and retest within 60 days, the retest is free. If you fail and do not retest within 60 days, you pay the full fee again for the next test.

What to do if your vehicle is out of state or you cannot test in your month

If you are out of state during your test month, you can test early — up to 60 days before your test month begins. For example, if your test month is June and you are leaving the state in May, you can test in April. This gives you a buffer if you travel.

If you miss your test month entirely, your registration becomes invalid when ready. You cannot legally drive the vehicle. To get back on track, you must test as soon as you can, and your new test month will be two years from that new test date. Contact the Colorado Department of Motor Vehicles if you need to update your registration after testing late.

Frequently Asked Questions

Do I need an emissions test if I just bought a used car in Colorado?

It depends on when the previous owner last tested it. If the vehicle is registered in Colorado, it follows the normal two-year test cycle based on the month on the registration. If you just bought it and the test is already overdue, you must test before you can legally drive it. Check the registration card to see when the test month is.

What if my vehicle is too old to test?

Vehicles older than 1975 are exempt from Air Care Colorado testing. Vehicles from 1975 onward must test. If you own a classic car that is registered as a classic vehicle, check with the Colorado Department of Motor Vehicles about exemptions — some specialty registrations have different rules.

Can I test at a station outside my county?

Yes. You can test at any Air Care Colorado station in the testing area, regardless of which county you live in. If you live in Denver but work in Boulder, you can test at a Boulder station. The only requirement is that you test during your test month.

What if I disagree with a failing result?

You can request a retest at the same station or a different station. If you believe the equipment was faulty, ask the station manager about their calibration records. You can also contact Air Care Colorado directly at 1-888-242-7333 to report a concern about a specific test result.

Do hybrid or electric vehicles need to test?

Hybrid vehicles must test like any other vehicle. Electric vehicles are exempt from Air Care Colorado testing because they produce no tailpipe emissions. If your vehicle is registered as electric-only, you do not need to test.