What Greeley requires for emissions testing

Greeley follows Colorado's statewide emissions testing program, which means your vehicle must pass an emissions test before you can renew your registration — but only if your vehicle is subject to testing. Not every vehicle in Greeley needs to test; the requirement depends on your vehicle's age, type, and where you registered it.

Vehicles registered in Weld County (where Greeley is located) that are model year 1981 or newer must test, with a few exceptions. Diesel vehicles, motorcycles, and vehicles registered outside Colorado are typically exempt. The test itself measures your vehicle's tailpipe emissions to may support they meet Colorado air quality standards.

You can have your vehicle tested at any Colorado emissions testing station, not just ones in Greeley. Many people test at stations near their home or workplace for convenience, but the results are valid statewide.

Key Takeaways

  • Weld County vehicles model year 1981 and newer must pass an emissions test before registration renewal, with limited exceptions for diesel and motorcycles.
  • The test costs between $20 and $30 and takes about 10 minutes at any Colorado testing station.
  • You can test at any station in Colorado, not just in Greeley, and the results transfer if you move or change registration location.
  • A failed test does not prevent you from driving; you have time to repair your vehicle and retest before your registration expires.
  • Testing stations in Greeley are open year-round, but demand is highest in the weeks before registration renewal important date.

Finding a testing station in Greeley

Colorado maintains a searchable list of all active emissions testing stations on the Department of Revenue website. You can search by city or ZIP code to find stations near you in Greeley. Most stations are independent repair shops, tire shops, or quick-lube facilities that have been certified to perform the test.

Call ahead before you go. Testing stations have different hours, and some require appointments during busy seasons. A few stations in Greeley operate on a walk-in basis, but you may wait 30 minutes to an hour during peak times, especially in the month before registration important date.

Bring your vehicle registration and a valid ID. The technician will need to see proof that your vehicle is registered in Colorado and that you are the owner or authorized to test it.

What happens during the test

The emissions test itself takes about 10 minutes. A technician will connect a probe to your vehicle's tailpipe and measure the levels of carbon monoxide, carbon dioxide, nitrogen oxides, and particulate matter. The vehicle must be running and warmed up, so arrive with your engine cold if possible — the test is designed to measure emissions from a cold start.

You will sit in the vehicle while the test runs. The technician will tell you when ready whether you passed or failed. If you pass, you receive a certificate that you can use to renew your registration online or at your county clerk's office.

If you fail, the certificate will show which emissions were too high. You do not need to repair your vehicle when ready; you have until your registration expires to fix the problem and retest. Many people fail once, make repairs, and pass on a second test.

Cost and payment

The test costs between $20 and $30 depending on the station. Most stations accept cash, debit, and credit cards. Some stations charge a small additional fee if you need to retest the same vehicle within a certain period, though Colorado law caps this fee.

The cost is separate from your registration renewal fee. You pay the testing station for the test, and then pay Weld County or the state when you renew your registration.

What to do if you fail

A failed test means your vehicle's emissions are above Colorado's limits for at least one pollutant. Common causes are a faulty oxygen sensor, a loose gas cap, a clogged air filter, or an engine problem. You do not have to repair it when ready, but you cannot renew your registration until you pass.

Take your vehicle to a repair shop and show them the failed emissions certificate. The technician can often diagnose the problem based on which emissions failed. Repairs range from $50 (replacing a gas cap or air filter) to several hundred dollars (replacing a catalytic converter or oxygen sensor).

After repairs, return to any emissions testing station and retest. You will pay the testing fee again. If you pass, you can proceed with registration renewal. If you fail a second time, the repair shop can help you troubleshoot further.

Timing your test before registration renewal

Your emissions test is valid for 120 days from the test date. Your registration renewal notice will show your expiration date. Test within 120 days before that date so your results are still valid when you renew.

Weld County sends renewal notices about 45 days before expiration. Many people test in the final 30 days, which creates long wait times at testing stations. If you test earlier, you avoid the rush and have time to repair and retest if needed.

You can renew your registration online through the Colorado Department of Revenue website, by mail, or in person at the Weld County Clerk's Office in Greeley. You will need your emissions test certificate (or the test results number if you tested online) to complete renewal.

Frequently Asked Questions

Do I have to test in Greeley, or can I test somewhere else in Colorado?

You can test anywhere in Colorado. The results are valid statewide and transfer if you move or change where you do business. Many people test at a station near their workplace or home, even if it is not in Greeley.

What if my vehicle is too new or too old to test?

Vehicles model year 1980 and older are exempt from testing. Very new vehicles (typically model year 2024 and newer) may also be exempt for their first few years. Check the Colorado Department of Revenue website or call your testing station to confirm your vehicle's status.

Can I renew my registration if I fail the emissions test?

No. You must pass the test or obtain a waiver before you can renew. If you make good-faith repairs and still fail, you may be able to request a waiver from Weld County, but this is uncommon and requires documentation of repair attempts.

How long does it take to get my test results?

You receive results when ready at the testing station. If you test in person, the technician prints your certificate on the spot. If you test online through a participating station, results are available within a few hours.

What if I move out of Weld County after I test?

Your test results remain valid for 120 days regardless of where you move. If you move to another Colorado county before your registration expires, you can use the same test results to renew in your new county.