All car owners who reside in Colorado must take their car for a regular vehicle inspection, completed at the DMV. Emissions testing is a part of the vehicle inspections done in some counties, and its purpose is to ensure that cars on the road are not emitting a high level of smog. Passing the smog check is mandatory for vehicles before a registration renewal.

The requirements for these inspections differ depending on the vehicle’s model year and fuel type. Vehicles being registered for the first time in emissions testing areas must also undergo testing. Review the following sections for more information on car emissions inspections in CO.

Colorado Emissions and Smog Check Requirements

The emission test requirements in Colorado generally vary depending on the car’s model year and fuel type. The type of inspection conducted will be contingent on these factors, each with slightly different criteria. There are five different types of smog checks that are administered in CO:

  • Onboard diagnostics (OBD)
  • Two-speed idle test
  • I/M 240 dynamometer (treadmill) test
  • RapidScreen Roadside test
  • Diesel emissions test

The OBD emissions test is conducted on gasoline-fueled or hybrid vehicles that are 8 to 11 years old. The standards for hybrid vehicles are the same as for gasoline-powered vehicles. Through this method of inspection, vehicles that display a “check engine” light will automatically fail.

The vehicle inspection for cars that are at least 12 years old but have a model year no earlier than 1982 will include the I/M 240 dynamometer test. It is possible to pass the treadmill smog test even if the “check engine” indicator is on. Gasoline-fueled cars manufactured before 1982 will undergo the two-speed idle test.

The DMV smog test for low-emissions vehicles is the RapidScreen Roadside test. The test for these types of vehicles does not require the car to be taken in for a physical inspection. Independent smog certification providers must be sought for diesel vehicle owners, as the Colorado Department of Public Health & Environment does not administer testing for diesel-powered vehicles.

Smog Check Exemptions in Colorado

Emissions testing in Colorado is not required for all vehicles. Vehicle testing is only mandatory in certain counties in the state, particularly those that are at risk for high smog levels. Even within these counties, the vehicle inspections are not mandatory for all vehicles.

Vehicle inspections are only compulsory for certain Colorado counties. Residents living outside of these counties are not subject to Colorado emissions testing, except in very special cases. Car owners living within the following counties are required to take their vehicle in for a smog inspection:

  • Boulder County
  • Broomfield County
  • Denver County
  • Douglas County
  • Jefferson County
  • Some parts of Adams, Arapahoe, Larimer, and Weld County

Emissions testing in Colorado is not required if the vehicle is:

  • A motorcycle, farm vehicle, moped or horseless carriage
  • 7 model years old or less
  • A collector’s vehicle with the model year of 1975 or older
  • Completely run by electric power

Out-of-State Emissions Testing in Colorado

The regular emissions testing requirement for Colorado residents is mandatory even if the car owner is living in another state temporarily. However, the state allows for testing to be done outside of CO, with a little extra paperwork.

Colorado residents who need to take have an inspection completed must first find a smog test provider in their temporary place of residence. If this region does not offer testing, any law enforcement officer may complete the inspection.

Once the vehicle inspection is completed, the car owner must send the test results to the Colorado DMV with a completed Application for an Affidavit of Emissions Extension (Form DR 2376). If the test was performed in a state that does not offer emission inspections, a Verification of Vehicle Identification Number (Form 2698) must also be included.

Emissions Waivers in Colorado

Car owners are eligible for CO DMV emissions testing waiver in certain cases. Car owners whose vehicle has failed inspection may be waived from the inspection if they have spent more than $715 in professional auto repairs necessary to pass the test. If the car model year is 1967 or older and did not pass the safety and emissions inspection, the owner must spend over $75 in repairs to be eligible for the waiver. The waiver is valid for one inspection.

A waiver for Colorado emissions testing may also be given to those experiencing economic hardship. The waiver may be awarded to car owners who are enrolled in a financial aid program to pay for car repairs and do not have any other means of transportation. There is no minimum amount of repairs that need to be made on the failed vehicle to qualify for the waiver.

Testing Fees in Colorado

The CO smog check price varies depending on the model year of the car. Most cars will require a $25 fee for testing, while others may subject to different prices. Owners of diesel-powered cars will be subject to the price quoted at the Diesel Emission Testing Center they choose to have their vehicle inspected at.

For emissions testing in Colorado, the cost of inspecting a gasoline powered car that was manufactured in 1982 or later is $25. Gasoline-fueled cars with a model year prior to 1982 will need a smog check more frequently at $15 each inspection. Diesel-powered cars must go to a special Diesel Emission Testing Center for a vehicle inspection, which charge prices independent of state government fees. Diesel testing centers can charge up to one labor hour of service.

Where to Perform an Emissions Check in Colorado

There are several emissions testing locations throughout Colorado, serving cities such as Denver, Boulder, Castle Rock, and Fort Collins. All smog check stations are open Monday through Friday, from 8:00 am until 5:30 pm and on Saturdays from 8:00 am until 1:00 pm. No emissions testing centers are open on Sundays or holidays.

Each location is an official Colorado DMV smog check provider and has licensed professionals conducting tests. Inspectors at inspection clinics are certified to perform emissions checks on many different types of vehicles. Employees will conduct the appropriate inspection depending on the make and model of the vehicle.

Failing a Colorado Smog and Emissions Check

The purpose of Colorado emissions testing is to make sure that no car on the road is giving off a dangerously high level of smog. Not every car that undergoes inspection will pass the test, especially if the car is older and has never been inspected before.

The first step to taking care of a failed DMV smog check in CO is to determine why the vehicle did not pass. The reason for a failed test can be found in the Vehicle Inspection Report, which is given to the car owner after the inspection is complete. Common reasons for failure include having a “check engine” indicator on, emitting too much carbon dioxide, the gas cap not functioning properly, or smoke from the tailpipe being thicker than the acceptable standard.

Next, the car owner can resolve the safety and emissions issue by going to a repair facility. The Vehicle Inspection Report will have a list of well-known repair providers, but the car owner can take the vehicle to any licensed auto shop of their choosing. The specific issues that prevented the vehicle from passing the inspection should be addressed. When the problems are fixed, the car owner can return to the vehicle emissions test provider for a retest.

Last updated on Tuesday, March 10 2020.