Larimer County residents are required to obtain a certificate of emissions control for vehicles within a designated area of Larimer County. The test is required on:

  • Newly purchased vehicle
  • Transfer of ownership
  • Vehicles being registered for the first time in Larimer County
  • Vehicles currently registered in Larimer County upon renewal (See below)

The registration renewal postcard will say Emission Test Required, if the vehicle is required to be tested:

  • Every two years for 1982 and newer model year vehicles.
  • Every year for 1981 and older models.
  • A seven year exemption is applicable on new vehicles starting the year of manufacture.

The 18 Envirotest-operated emissions testing centers perform both the enhanced I/M 240 test for 1982 and newer vehicles, and the two-speed idle test for 1981 and older vehicles. 1981 and older vehicles may also be tested at an independent test center. For information on locations of these centers, call (303) 692-3270.

Test Locations in and near Larimer County

  • 7001 N Franklin Ave, Loveland (4 blocks northwest of the WalMart Store, Highway 287 and 71st st)
  • 835 SE Frontage Rd., Fort Collins (South East Corner of the I-25 and Highway 14 intersection)
  • 5222 Silver Peak Ave., Dacona (East of I-25, North of Co Rd 12)
  • 2844 W. 30th St., Greeley (West of the Greeley Mall)

Hours: Monday through Friday, 8 a.m. to 5:30 p.m.; Saturday, 8 a.m. to 1 p.m.
Phone: (970) 247-8378 or (970) AIR-TEST

RapidScreen Program

To reduce the number of vehicles requiring a traditional emissions inspection, a RapidScreen Program has been established for northern Colorado and the Denver area. Clean vehicles that pass a drive-by roadside test can forego a trip to the emissions inspection station if they receive a notification in the mail saying they passed RapidScreen. The applicable emissions fee of $25.00 will be added to the registration renewal. The RapidScreen Program utilizes remote sensing to measure emissions as vehicles drive past roadside monitors. The monitors measure emissions and record license plate numbers.

Visit the RapidScreen website for information on locations

Diesel emission is required in Larimer County within a designated area of Larimer County. Test requirements are based on the appropriate Gross Vehicle Weight Rating. Related information can be found on the Department of Revenue website or you may call (303) 205-5603 or (303) 744-2442.

Gross Vehicle Weight Rating (GVWR)

  • Heavy-duty diesel vehicles – GVWR of 14,001 lbs. or more
  • Light-duty diesel vehicles – GVWR of 14,000 lbs. or less


The diesel emission testing facilities can charge up to one-hour of the posted labor rates. There is no set fee.

Exempt Vehicles

Heavy-duty diesel vehicles are exempt from emissions for the first four model years. Light duty diesel vehicles are exempt for the first four model years. After the exemption period, vehicles are required to be tested as instructed in Vehicle Emissions Testing Cycles below.

Vehicle Emissions Testing Cycles

  • Light-duty diesels that are 2003 and older are required to have an emissions test every year.
  • Light-duty diesels that are 2004 and newer are required to have an emissions test every 2 years.
  • Heavy-duty diesels that are less than 10 model years old are to have an emissions test every 2 years.
  • Heavy-duty diesels that are more than 10 model years old are to have an emissions test every year.

Diesel Emission Station Locations

The State of Colorado may approve an emission extension for the following reasons:

  • Out of State Student - Vehicle owner and/or immediate family member who is out of state attending school on a full-time basis. Student ID number is required.
  • Out of State Active Military - Vehicle owner and/or spouse who is out of state on active duty in a branch of the United States military. Military individual must be the owner or co-owner of the vehicle. Military ID number is required.
  • Colorado Resident Seasonally Out of State - Vehicle owner who spends a portion of the year (less than 12 months) and returns the vehicle to Colorado every year. It is strongly recommended that the vehicle owner change the registration cycle to coincide with when the vehicle is in Colorado to avoid Emission Extensions every year.
  • Vehicle Disabled Out of State - Vehicle owner and/or immediate family member who had the vehicle out of state when it became disabled due to a vehicle accident or engine trouble. Must provide receipts from the repair shop or body shop where services are provided, and or any accident report if applicable.
  • Colorado Resident Working Out of State - Vehicle owner and/or immediate family member who is working in any capacity out of state. NOTE: Some states require registration if individual is working in their state (i.e. Alabama, Alaska, Arizona, California, Florida, Louisiana, Montana, Nevada, North Dakota, Texas, Utah and Wyoming).
  • Colorado Resident Temporarily Out of State - Vehicle owner and/or immediate family member who is temporarily out of state for family emergency, caring for a sick relative, settling family estate, etc.

For all extensions: If the state which the vehicle is currently in requires emissions testing, you must submit a PASSING emissions test from the state with your application (except for reason "D"). If an emissions test is not required, you must submit a vehicle identification number VIN inspection (DR2698) from the state the vehicle is currently in, to be completed by law enforcement ONLY, with your application.

While an approved extension will exempt your vehicle from the Colorado Emissions requirements, you may be in violation of other states vehicle registration laws, in which you currently reside. You may be required to register your vehicle in that state. You are advised to contact the local vehicle registration office for more information.

Vehicles registered using only a VIN Verification MUST be emission tested within 15 days upon returning to Colorado. Owners of vehicle that do not comply with the inspection requirements upon return to Colorado are subject to penalties as defined in 42-3-313 CRS.

Once the vehicle returns to Colorado, the vehicle owner MUST contact his or her County Clerk's Office to have his or her registration mailing address changed back to a Colorado address.

Emission Extension Form (DR2376)


  1. Effective July 1, 2010 gasoline operated vehicles will require proof of emission to register or renew the registration. Please see the State Emissions website for details.

    Diesel emission is required in Larimer County. Related information can be found on the Department of Revenue website.

  2. If you are driving into an enhanced emissions area more than 90 days per year, you are required to obtain an enhanced emissions test. These are only done in the metro area at stations run by Envirotest dba Air Care Colorado. See State emissions

  3. If you are going to be in the State of Colorado for more than 30 days, you will need to comply with Colorado emissions standards.