Indiana requires emissions testing in only a few counties, and most of the state does not

Indiana does not have a statewide emissions inspection program. Only three counties—Marion, Hamilton, and Hendricks—require emissions testing as part of vehicle registration. If you live outside those counties, you will not need to pass an emissions test to register your vehicle, no matter how old it is or what it runs on.

If you do live in one of the three counties that require testing, you must pass an emissions inspection before you can renew your registration. The test checks whether your vehicle's exhaust meets state pollution standards. Vehicles that fail can still be registered, but only after repairs are made and the vehicle passes a retest.

The emissions program in Indiana is run by the Indiana Department of Environmental Management (IDEM), which sets the standards and oversees the testing stations. The actual testing is done at certified private repair shops and inspection facilities throughout the three counties.

Key Takeaways

  • Only Marion, Hamilton, and Hendricks counties in Indiana require emissions testing; the rest of the state has no emissions inspection requirement.
  • The test measures what comes out of your tailpipe to may support it meets state pollution limits, and is required before you can renew your vehicle registration in those counties.
  • Vehicles that fail can still be registered temporarily while you make repairs, then you return for a retest at no additional cost.
  • The test costs between $15 and $25 depending on your vehicle type and the testing station, and takes about 15 minutes.

Which vehicles must be tested in Indiana's three counties

In Marion, Hamilton, and Hendricks counties, most vehicles registered there must pass an emissions test. This includes passenger cars, light trucks, and SUVs. Diesel vehicles are tested under a separate standard. Motorcycles, mopeds, and vehicles registered as antiques or classics are exempt from testing.

Vehicles that are brand new to the state—meaning you just moved to Indiana or bought a vehicle out of state—are usually exempt from testing for the first two years of registration in the state. After that, they fall under the same requirements as other vehicles. Check with your county's Bureau of Motor Vehicles office to confirm your vehicle's status before you register it.

Vehicles that are more than 30 years old are also exempt, even in the three testing counties. The exemption is based on the model year, not the current condition of the vehicle.

What the emissions test actually measures

The test checks two main things: how much nitrogen oxide (NOx) and how much particulate matter your vehicle produces. The technician connects a probe to your tailpipe and reads the emissions while the engine runs at idle and at a higher speed. The whole process takes about 15 minutes.

Your vehicle passes if the readings fall below the limits set by IDEM. Those limits are based on your vehicle's model year and engine type—newer vehicles have stricter limits than older ones, because newer engines are designed to produce less pollution. A 2005 sedan will have different pass/fail numbers than a 2015 sedan.

The test does not check whether your check engine light is on, whether your gas cap is loose, or whether your vehicle has been properly maintained. It only measures what is actually coming out of the tailpipe at the moment of the test.

How to find a testing station and what it costs

You can find certified testing stations on the IDEM website or by calling your county's Bureau of Motor Vehicles. Most repair shops in the three counties are certified to perform the test, so you have multiple options. You do not have to use the same shop where you get your oil changed or repairs done—any certified station will do.

The test costs between $15 and $25, depending on whether your vehicle is gasoline or diesel and which testing station you choose. Some shops charge a flat fee; others charge slightly different amounts. Call ahead if you want to know the exact price before you go in.

You can get tested any time during your registration renewal period. You do not have to wait until the last day, and testing early gives you time to make repairs if you fail. Many people test a few months before their registration expires for exactly this reason.

What happens if your vehicle fails the test

If your vehicle fails, you will receive a written report showing which emissions were too high. You can still renew your registration, but only for 30 days. This gives you time to have the vehicle repaired and retested without losing your registration.

Common reasons for failure include a faulty oxygen sensor, a clogged fuel injector, a bad catalytic converter, or an engine that is running too rich (burning too much fuel). A mechanic can read your vehicle's diagnostic codes to narrow down the problem. Some repairs are straightforward and inexpensive; others can cost several hundred dollars.

Once you have made repairs, you can return to any certified testing station for a retest. The retest is free—you only pay for the initial test. If you pass the retest, you can complete your registration renewal. If you fail again, you have another 30 days to make further repairs.

Vehicles that consistently fail and repair options

If your vehicle fails the retest, you have a few options. You can continue making repairs and retesting until it passes. You can also request a waiver from IDEM if you have spent at least $300 on repairs and the vehicle still does not pass. The waiver allows you to register the vehicle anyway, though you will need to retest the following year.

Some vehicles—particularly older ones with high mileage—may never pass because the emissions systems have degraded beyond repair. In those cases, a waiver is often the only way to keep the vehicle registered. You will need documentation of the repairs you attempted and the costs you paid.

If you are considering replacing the vehicle, keep in mind that a newer used vehicle will almost certainly pass emissions testing and will cost less to maintain overall. The decision depends on how much the repairs would cost and how much longer you plan to keep the vehicle.

Frequently Asked Questions

Do I need emissions testing if I just moved to Indiana?

Only if you move to Marion, Hamilton, or Hendricks county. If you move to any other Indiana county, you do not need emissions testing. If you move to one of the three counties, your vehicle is usually exempt for the first two years after you register it in Indiana. After that, you must test it like any other vehicle.

Can I register my vehicle without passing the emissions test?

In the three testing counties, no—you cannot complete registration without passing the test. However, if you fail, you can register for 30 days while you make repairs. After that, you must pass a retest to renew your registration again.

What if my vehicle has a check engine light on?

A check engine light does not automatically fail you on the emissions test. The test only measures what comes out of the tailpipe. However, a check engine light usually means something is wrong with the engine or emissions system, and that problem might cause you to fail. Have the code read before you test so you know what you are dealing with.

How often do I need to test my vehicle?

Once per year, when you renew your registration. If you pass, you do not test again until the next renewal. If you fail and get a 30-day waiver, you must retest within that 30 days before you can renew again.

What if I sell my vehicle to someone in Indiana?

The new owner is responsible for passing the emissions test before they can register it in their name. If they buy it in a non-testing county and move it to a testing county, they will need to pass the test as part of their first registration in that county.