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:

  • Vehicles being registered for the first time in Larimer County
  • Vehicles currently registered in Larimer County upon renewal 
  • Newly purchased vehicles
    • Gasoline vehicles are exempt from an emissions test for the first seven model years.
    • Diesel vehicles are exempt from an emissions test for the first four model years. 
  • Transfer of ownership
    • If the ownership of a gasoline vehicle is being transferred in the last year of the seven year exemption, an emissions test will be required. For example, in 2024, an emissions test will be required if the ownership of a model year 2018 is transferred.
    • If the ownership of a diesel vehicle is being transferred in the last year of the four year exemption, an emissions test will be required. For example, in 2024, an emissions test will be required if the ownership of a model year 2021 is transferred.
  • Collector vehicles
    • Vehicles that are 1975 and older registered with 5-year Collector plates are not required to have an emissions test. 
    • Vehicles that qualify for the 5-year Collector plates but require an emissions test are model years 1976 - 1990. A completed DR2839 Collector's Item Affidavit is required.   

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 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.

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 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.

2023 emissions requirements for a diesel vehicle

Model Year Diesel Testing Frequency of Test Testing Fee
2024 Exempt n/a


2023 Exempt n/a n/a
2022 Exempt n/a n/a
2021 Renewals are exempt n/a n/a
Need test if transfer of ownership Every two years Rates vary per diesel center
2015* - 2020 Need Test Every two years Rates vary per diesel center
1993-2014 Need Test Annually Rates vary per diesel center

1976 - 1992

with collector plates

Need test Every five years Rates vary per diesel center

1976 - 1992

without collector plates

Need test Annually Rates vary per diesel center

1976 or newer

Grandfathered with Collector Plates**

Exempt n/a n/a

1975 and older

with Collector Plates

Exempt n/a n/a

1975 and older

without Collector Plates

Need test Annually Rates vary per diesel center

*Transition from biennial to annual testing is based on the MSO (Manufacturer Statement of Origin) date of the vehicle. See local County DMV for more information.

**Vehicles model year 1976 or newer that have been registered with Collector Plates prior to September 1, 2009, and the registration has never lapsed or expired.

Diesel Emission Station Locations

Please note: Call to verify the availability of test type, hours, etc. before proceeding to the 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)

You may also apply for an out of state emission extension online at the State of Colorado website.

Request Emission Extension


  1. 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

  2. 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.

  3. Kit cars, all-electric vehicles, motorcycles, horseless carriage and vehicles registered as street rods are exempt from emissions testing requirements.

  4. A map view is available here that shows the emission areas. You can also enter your address directly here