What You Need to Know About Emissions Testing in Connecticut

CT emissions tests are required in every county. Certain vehicles may be exempt—like fully electric vehicles, motorcycles, and vehicles 4 years old or newer.
Written by Andrew Biro
Reviewed by Melanie Reiff
Bi-annual emissions testing is required for every Connecticut-registered vehicle built between the 1996 and 2018 model years—unless said vehicle meets one or more of the exemption requirements.
  • To combat air pollution, certain vehicles in Connecticut are required to undergo routine vehicle emissions testing before you can renew your registration.
  • CT emissions tests are required in every county, but certain vehicles may be exempt—like fully electric vehicles, motorcycles, and vehicles four years old or newer.
  • If you live in an area where smog testing is required, you'll need to determine whether your car meets the requirements and, if it does, schedule regular smog checks.

Which counties in Connecticut require emissions testing?

Not every state chooses to enforce or require routine emissions testing, but Connecticut does—and to a higher degree than most. 
Emissions testing reduces the amount of harmful state emissions, including hydrocarbons and carbon monoxide, entering the atmosphere and to improve the local air quality, especially in urban centers with denser populations.
While most states only impose emissions testing for vehicles registered in densely-populated urban areas, the state of Connecticut requires every vehicle registered within its borders to undergo emissions testing once every two years—regardless of the city or county it’s registered in.
To cover all of our bases, this includes:
  • Fairfield County
  • Hartford County
  • Litchfield County
  • Middlesex County
  • New Haven County
  • New London County
  • Tolland County
Pro Tip: You can search for your
vehicle's emissions test due date
online by entering its vehicle identification number (VIN) on the Connecticut Emissions Program website. You should also receive an official notice within 45 days of the due date—as long as the Department of Motor Vehicles (DMV) has your current mailing address and other contact information.

Which cars need emissions testing in Connecticut?

As stated, pretty much every vehicle in Connecticut is required to undergo emissions testing, unless it meets one or more of the exemption requirements. 
Testing is generally required for every vehicle built between 1993 and the last seven model years. 
The state guidelines are a little complicated, so let’s go into more detail: 
  • If your car was built prior to 1993 or is fewer than seven model years old: It is exempt from emissions testing.
  • If your vehicle is exactly seven model years old: You’ll need to have it tested only upon transfer of ownership.
  • If your vehicle is older than seven model years but newer than 1992: It needs to undergo testing once every two years.

Exemptions from Connecticut emissions testing

Certain types of vehicles are exempt from Connecticut emissions vehicle testing, some of which have already been mentioned. 
Here’s the complete list of exempt vehicles:
  • Non-hybrid electric vehicles
  • Motorcycles, mopeds, and motorized bicycles
  • Agricultural equipment
  • Vehicles weighing more than 10,001 lbs
  • Type II diesel school buses
  • Vehicles manufactured within the last 4 model years
  • Vehicles built in the 1996 model year or older
  • Vehicles with a composite title

How does emissions testing work in Connecticut?

If your vehicle meets the above requirements for emissions testing in Connecticut, follow the steps below to schedule and complete an inspection:
  1. Locate a testing center: To find a nearby testing center, visit the Connecticut Emissions Program’s website
    and enter your zip code.
  2. Schedule an inspection: Once you’ve located a verified testing center, schedule an inspection for a date prior to your vehicle registration’s expiration date.
  3. Bring your vehicle in for testing: Drive to your testing location on the date of your smog check appointment and follow any instructions you are given.
  4. Pay the testing center’s fee: Once the inspection is over, pay the $20 testing fee.
If you passed your Connecticut emissions testing, you won’t need to return for another two years—but if you failed, you’ll need to address the issue and schedule a retest.

Types of emissions tests

Connecticut administers several different types of emissions tests depending on the age, weight, and fuel type of your vehicle. 
These emissions inspections include: 
  • On-Board Diagnostic (OBD) test: if your vehicle was manufactured in 1996 or later (gasoline or diesel) or built in 1997 or later and weighs between 8,501 lbs and 10,000 lbs (diesel), a technician will scan your engine computer for any emissions-related error and maintenance codes that may require attention.
  • Acceleration Systems Mode test: if your vehicle is older than the 1996 model year and weighs less than 8,500 lbs, a technician will drive it on a giant treadmill of sorts at 25 mph under a 25% weight load.
  • Pre-Conditioned Two-Speed Idle test: if your vehicle is older than the 1996 model year, has traction control, all-wheel drive, or weighs over 8,500 lbs, test personnel will measure its emissions while in Park or Neutral at two different RPMs.
  • Gas Cap Pressure test: if you drive a gasoline-fueled vehicle that was made in the 1995 model year or earlier, a technician will test whether your gas cap seals properly.

What happens if you fail emissions testing in Connecticut?

If your vehicle fails emissions testing in Connecticut for any reason, you will have 60 days to remedy the mechanical issue and retest your vehicle. 
There are a number of reasons your vehicle might not pass an emissions test, including: 
  • Fluid leaks
  • Evidence of tampering with exhaust system components
  • Missing catalytic converter
  • Mechanical problems, such as with your engine or transmission
  • Animals in your vehicle at inspection time
  • Nonfunctioning odometer
Keep in mind: You are only allotted one free retest per testing cycle—each additional one will cost $20.
In order to diagnose the cause of your emissions testing failure, it is recommended you visit one of Connecticut’s Certified Emissions Repair Facilities (CERT), but you can ultimately choose any automotive repair facility you like.
If your vehicle still does not pass the retest, you can call the state DMV Emissions Division at (860)-263-5611 to apply for one of Connecticut’s three emissions testing waivers:
  • Cost waiver
  • Functional Diagnosis waiver
  • Economic Hardship waiver
If your application is accepted, you will not have to meet the emissions test requirements for the duration of that test cycle.
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Regardless of the vehicle you drive, you will not need to schedule an emissions test every year in Connecticut—but you may need to schedule one every other year. 
Most vehicles (especially cars and trucks) manufactured between the model years 1996 and 2018 are required to undergo emissions testing on a bi-annual basis. 
Generally speaking, the only way to legally avoid emissions testing is if you drive a vehicle that is exempt from such inspections. 
If your car is not exempt from emissions testing, it’s in your best interest not to circumvent the legal requirements—it could result in your registration renewal being denied.
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