What Wisconsin requires for emissions testing

Wisconsin requires emissions testing for most vehicles registered in Dane County (Madison area) and Milwaukee County. If you live outside those two counties, your vehicle does not need an emissions test to register. If you live in one of the covered counties, you must pass an emissions test every two years as part of your vehicle registration renewal.

The test checks whether your vehicle's exhaust meets state pollution standards. A technician will connect a diagnostic machine to your vehicle's onboard computer and may also perform a tailpipe test depending on your vehicle's age and type. The whole process usually takes 15 to 30 minutes.

Vehicles that are model year 1968 or older, diesel-powered vehicles, and motorcycles are exempt from the test. If your vehicle has a check engine light on, you will fail the test — the light must be off before you can pass.

Key Takeaways

  • Only vehicles registered in Dane County or Milwaukee County must pass an emissions test in Wisconsin; all other counties have no emissions testing requirement.
  • The test is required every two years when you renew your vehicle registration, and you cannot complete registration without a passing result.
  • Your vehicle's check engine light must be off before testing, or you will automatically fail.
  • You can have the test done at any Wisconsin emissions testing station, not just one location, and the cost varies by station but typically ranges from $15 to $30.
  • If your vehicle fails, you have 60 days to fix the problem and retest at no additional charge before your registration expires.

Where to get your vehicle tested in Wisconsin

The Wisconsin Department of Transportation maintains a list of all licensed emissions testing stations on its website. You can search by county or city to find stations near you. Both independent repair shops and new-car dealerships can perform emissions tests — you do not have to go to a dealership.

Call ahead before you go. Some stations are busy during certain times of day or week, and a few may have limited hours. Ask whether they can test your specific vehicle type, since some stations have equipment limitations for older vehicles or specialty vehicles.

The cost is not set by the state, so different stations charge different amounts. Most charge between $15 and $30 for the test itself. If your vehicle fails and needs repairs, the repair cost depends on what is wrong — that is separate from the test fee.

What happens if your vehicle fails the emissions test

A failure means your vehicle's emissions are above the legal limit for one or more pollutants. The testing station will give you a written report showing which emissions failed and what the readings were. This report is important — keep it, because you will need it if you take your vehicle to a repair shop.

You have 60 days from the test date to fix the problem and retest. The retest is free at the same station where you failed, as long as you come back within that 60-day window. If you miss the 60-day important date, you will have to pay for a new test.

Common reasons for failure include a faulty oxygen sensor, a bad catalytic converter, a fuel leak, or a malfunctioning fuel injector. A mechanic can diagnose the specific problem using the failure report. Some repairs are straightforward and inexpensive; others are more costly. If you cannot afford the repair right away, contact your testing station about your options — some stations or repair shops may have information about information programs.

How to prepare your vehicle before testing

Make sure your check engine light is off. If it is on, have a mechanic scan the vehicle's computer to find out why before you go for the test. Fixing the underlying problem is usually necessary before the light will turn off.

Your vehicle should be in normal operating condition. The engine should start easily, run smoothly, and not have any obvious leaks. If your vehicle has been sitting unused for a long time, drive it for at least 15 to 20 minutes before the test — this helps the engine reach normal operating temperature, which affects emissions readings.

Bring your vehicle registration or proof of ownership. Some stations may ask for your driver's license as well. You do not need to make an appointment at most stations, but calling ahead to ask about wait times is a good idea.

Emissions testing and vehicle registration timing

Your emissions test result is tied to your vehicle registration renewal. When you renew your registration, you must show proof of a passing emissions test from within the past 60 days. If you do not have a passing test, the Wisconsin Department of Transportation will not issue or renew your registration.

You can take the emissions test up to 60 days before your registration expires. Many people do this early to avoid a last-minute rush. If your registration expires before you pass the test, you cannot legally drive the vehicle, even if you have an appointment scheduled.

Once you have a passing test result, take it to your registration renewal location — either your local DMV office or an authorized agent — along with your other renewal documents. The test result is valid for two years from the date you passed it.

What to do if you cannot pass the emissions test

If your vehicle repeatedly fails the test even after repairs, you have a few options. First, get a second opinion from a different mechanic. Sometimes the first diagnosis is wrong, and a second shop may identify a different problem that is actually causing the failure.

Second, ask the testing station whether your vehicle qualifies for a waiver. Wisconsin allows waivers in limited cases — for example, if you have spent $500 or more on repairs in the past 12 months and the vehicle still fails, you may be may be able to access for a waiver that allows you to register anyway. The testing station can tell you whether your situation qualifies.

Third, consider whether the vehicle is worth fixing. If repair costs are very high and your vehicle is old, you may decide it makes more sense to replace the vehicle than to keep repairing it. This is a personal financial decision, but it is worth thinking through before you spend a lot of money on a failing vehicle.

Emissions testing for out-of-state vehicles

If you are moving to Wisconsin from another state and registering your vehicle in Dane or Milwaukee County for the first time, you will need an emissions test before you can complete registration. You cannot use an emissions test from another state — Wisconsin requires a test performed at a Wisconsin testing station.

Plan for this when you move. Get your vehicle tested within 60 days of your move so you have a passing result ready when you go to register. If your vehicle fails, you will need time to make repairs before your registration important date.

If you are registering a vehicle that was previously registered in a Wisconsin county without emissions testing (such as a rural county), and you are now moving it to Dane or Milwaukee County, the same rule applies — you need a new test at a Wisconsin station.

Frequently Asked Questions

Do I need an emissions test if I just bought a used car in Wisconsin?

Only if you are registering it in Dane or Milwaukee County. When you register the vehicle, you must show proof of a passing emissions test from within the past 60 days. If the previous owner did not provide a test result, you will need to get one before you can complete registration.

What if I fail the test and cannot afford to fix my vehicle right now?

You have 60 days from the test date to fix the problem and retest for free. If you cannot afford repairs within that window, ask the testing station or a local repair shop whether they know of any information programs. Some nonprofits and community organizations offer vehicle repair help for low-income drivers, though availability varies by county.

Can I drive my vehicle if my registration expired but I have a passing emissions test?

No. You must have both a passing emissions test and a current registration to drive legally. If your registration has expired, you cannot drive the vehicle even if you have the test result. Renew your registration as soon as you have the passing test.

How long does a passing emissions test result stay valid?

A passing test is valid for two years from the date you passed it. When you renew your registration in two years, you will need a new test. If you move out of Dane or Milwaukee County, you do not need another test — the requirement only applies in those two counties.

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

Some vehicles have equipment or design features that make them difficult to test at certain stations. Try a different testing station — they may have different equipment or experience with your vehicle type. If no station in your area can test your vehicle, contact the Wisconsin Department of Transportation for guidance on how to proceed with registration.