What Indiana's emissions test covers and who needs it

Indiana requires emissions testing for most vehicles registered in Marion, Lake, and Porter counties — the three counties that fall under the Indianapolis and Gary metropolitan areas. The test measures what comes out of your tailpipe: carbon monoxide, nitrogen oxides, and particulate matter. A vehicle passes if it stays within the state's limits for those pollutants.

You need an emissions test before you can register or renew registration in those three counties. If you live outside them, you do not need one. Diesel vehicles, motorcycles, and vehicles model year 1967 and older are exempt. Vehicles registered as non-road use (farm equipment, for example) do not need testing either.

The test itself takes about 10 to 15 minutes. A technician plugs a probe into your vehicle's onboard diagnostic port — the same port a mechanic uses to read engine codes — and records the readings. You get a pass or fail result on the spot.

Key Takeaways

  • Only vehicles registered in Marion, Lake, and Porter counties must pass an emissions test; all other Indiana counties have no emissions testing requirement.
  • The test measures tailpipe emissions and takes 10 to 15 minutes at a licensed testing station.
  • You must pass before you can register or renew your vehicle in one of the three required counties.
  • If you fail, you have 30 days to repair your vehicle and retest at no additional charge.
  • Testing stations are scattered throughout the three counties, and you can test at any licensed station regardless of where you live.

Finding a testing station and scheduling

The Indiana Department of Environmental Management (IDEM) maintains a list of licensed emissions testing stations on its website. You can search by county or city to find stations near you. Most stations do not require an appointment — you can walk in during business hours — but some do, so call ahead if you want to be sure.

Testing stations are typically repair shops, tire shops, or dedicated inspection facilities. The cost varies by station but usually falls between $15 and $25. Bring your vehicle registration and a photo ID. If your vehicle's check engine light is on, the station will fail it automatically, so have that repaired first.

You can test at any licensed station in the three counties, even if you do not live there. If you live in Marion County but work in Lake County, you can test near your workplace. The results are recorded in the state system and count toward registration in any of the three counties.

What happens if you fail the test

A failure means your vehicle's emissions are above the state limits. The testing station will give you a printed report showing which pollutants exceeded the limits. You then have 30 days to repair your vehicle and return to any testing station for a retest. The retest is free — you pay the testing fee again, but not a repair fee.

Common reasons for failure include a faulty oxygen sensor, a bad catalytic converter, a clogged air filter, 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. If you take it to a shop, bring the failure report so the mechanic knows what to focus on.

If you cannot afford repairs, some counties offer repair information programs. Contact your county's health department or IDEM directly to ask whether a program exists in your area and what the income limits are.

Timing for registration and renewal

You must have a passing emissions test before the Bureau of Motor Vehicles (BMV) will issue or renew your registration. If your registration is about to expire, do not wait until the last week — testing stations can get busy, and you may not have time to fail, repair, and retest before your important date.

A passing test result is valid for two years from the date of the test. If you test in January 2024, that result covers registration renewals through January 2026. You do not need to test again until after that window closes.

When you go to the BMV to register or renew, bring your passing test result. The BMV will record it in the system. If you do not have a passing result, the BMV will not complete your registration.

Vehicles that are exempt or have special rules

Diesel vehicles are exempt from emissions testing in Indiana, even in the three required counties. Motorcycles, mopeds, and vehicles with a model year of 1967 or earlier are also exempt. If your vehicle is registered as a historic vehicle or collector vehicle, you may be exempt — check with the BMV about your specific registration type.

Hybrid vehicles must still test. Electric vehicles are exempt because they produce no tailpipe emissions. If you own a plug-in hybrid, it must test because it has a combustion engine that runs part of the time.

Vehicles registered for non-road use — such as farm equipment or vehicles used only on private property — do not need emissions testing. If you have questions about whether your vehicle type is exempt, call IDEM or your county health department before paying for a test.

Moving to or from Indiana's testing counties

If you move into Marion, Lake, or Porter County from elsewhere in Indiana or from another state, you must obtain a passing emissions test before you can register your vehicle in that county. You have until your registration expires or until you transfer your registration, whichever comes first. New residents should test within 30 days of moving to avoid registration delays.

If you move out of the three counties to another part of Indiana, you no longer need emissions testing. When you renew your registration in your new county, you will not be asked for a test result. Your old test result becomes irrelevant.

If you move out of Indiana entirely, the same rule applies — no test is required in other states (though some states have their own emissions programs). Keep your passing test result for your records in case you move back to one of the three counties within two years.

Frequently Asked Questions

Can I test my vehicle before my registration expires?

Yes. You can test at any time, and the result is valid for two years. Testing early gives you time to repair and retest if you fail, without rushing before a registration important date.

What if I fail the retest after repairs?

You have another 30 days to make further repairs and test again. The second retest is also free. If you fail a second time, contact a mechanic or your county health department — some shops specialize in emissions repairs, and your county may have a repair information program.

Do I need emissions testing if I buy a used car from a dealer?

The dealer handles the sale and transfer of registration. You will need a passing emissions test before the BMV completes the registration transfer in your name, unless the vehicle is exempt. Ask the dealer whether the vehicle has a current passing test or whether you need to obtain one.

What if the testing station says my vehicle cannot be tested?

This usually means your vehicle's check engine light is on, or the diagnostic port is damaged or inaccessible. Have the check engine light issue repaired first, then return to test. If the port is damaged, a mechanic can help you locate and repair it.

Where do I find the list of testing stations?

Visit the Indiana Department of Environmental Management website and look for the emissions testing station locator. You can search by county or city. Call ahead to confirm hours and whether an appointment is needed.