States That Require Emissions Testing

Thirty-five states and the District of Columbia currently operate some form of vehicle emissions testing program. However, the rules vary significantly: some states test all vehicles, others only test cars over a certain age, and some test only in specific counties or metropolitan areas. The federal government does not run these programs — each state designs its own requirements, chooses which vehicles to test, and decides how often testing must happen.

The states with statewide emissions programs are Arizona, California, Colorado, Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Nevada, New Hampshire, New Jersey, New Mexico, New York, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island, Tennessee, Texas, Utah, Vermont, Virginia, Washington, West Virginia, Wisconsin, and Wyoming. The District of Columbia also runs a program. This list changes occasionally as states add or remove requirements, so your state's current status depends on when you are reading this.

Key Takeaways

  • Thirty-five states plus Washington, D.C. have emissions testing programs, but the rules about which vehicles must be tested and how often vary by state.
  • Some states test all vehicles; others test only vehicles over a certain age or only in specific counties near major cities.
  • Your state's Department of Motor Vehicles or Department of Environmental Quality website lists local testing stations and current requirements for your vehicle.
  • Testing frequency ranges from every two years to every four years depending on your state and vehicle age.
  • If your vehicle fails, you typically have 30 to 60 days to repair it and retest at no additional cost.

How to learn about Your State Tests Vehicles

The fastest way to confirm whether your state requires emissions testing is to visit your state's Department of Motor Vehicles website and search for "emissions testing" or "vehicle inspection." Most state DMV sites have a dedicated page listing which counties or regions conduct testing, which vehicle model years are affected, and how often you must test.

If your state does have a program, the DMV website will also show you where testing stations are located near you. Some states contract with private repair shops to conduct tests; others run state-owned facilities. The website will tell you the current cost (which ranges from $15 to $50 depending on the state) and whether you can schedule an appointment online or must walk in.

States With Partial or Regional Testing Requirements

Several states do not test all vehicles statewide but instead require testing only in certain areas. Texas, for example, tests vehicles in the Houston, Dallas-Fort Worth, and Austin metropolitan areas but not in rural counties. New York tests vehicles in the New York City area and surrounding counties but not upstate. Colorado tests in the Denver metropolitan area. Georgia tests in the Atlanta area. These regional programs exist because federal air quality standards explore only to counties that do not meet national pollution limits.

If you live in a state with regional testing, check your county name on your state's DMV or environmental quality website to see whether your area is included. If you move from a testing county to a non-testing county within the same state, you may no longer need to test your vehicle — but you should verify this before your current test expires.

Age and Vehicle Type Restrictions

Not all states test all vehicles. Many states exempt vehicles under a certain age — commonly four, five, or eight years old — because newer cars produce fewer emissions. Some states test only gasoline-powered vehicles and exempt diesel trucks or motorcycles. A few states test commercial vehicles separately or not at all.

Your state's DMV website will specify which model years and vehicle types are subject to testing. If you own a vehicle that falls outside the testing requirement, you do not need to test it, but you should confirm this in writing on your state's official website rather than assuming based on the vehicle's age or type.

Testing Frequency by State

States set their own testing schedules. Most require testing every two years, but some require it every four years, and a few require it annually. Your test results are typically valid for the period your state sets — usually printed on your inspection sticker or recorded in the DMV database — and you cannot renew your vehicle registration without a current passing test in states that require one.

Your state's DMV website will show you when your vehicle's next test is due. Many states send renewal notices by mail or email when a test is approaching. If you miss the important date, you may not be able to renew your registration until you test and pass.

What Happens If Your Vehicle Fails

If your vehicle fails emissions testing, you typically have 30 to 60 days (depending on your state) to have it repaired and retested. Most states allow you to retest at no additional charge during this grace period. You do not need to return to the same testing station — any station in your state will accept a retest.

Common reasons for failure include a faulty oxygen sensor, a loose gas cap, a malfunctioning catalytic converter, or an engine light that is on. Many repair shops can diagnose the problem for $50 to $150 and fix it for $200 to $800, depending on the issue. Some states offer repair information programs or tax credits for low-income vehicle owners who need emissions-related repairs, though these vary widely.

States Without Emissions Testing

Fifteen states do not require emissions testing: Alabama, Alaska, Arkansas, Florida, Hawaii, Idaho, Iowa, Kansas, Mississippi, Missouri, Montana, Nebraska, North Dakota, Oklahoma, and South Dakota. If you live in one of these states, you do not need to test your vehicle for emissions, though you may still need to pass a safety inspection depending on your state's rules.

If you move from a testing state to a non-testing state, you will no longer need to test your vehicle. If you move from a non-testing state to a testing state, you will need to test your vehicle before you can register it there.

Frequently Asked Questions

Do I need emissions testing if I just moved to a new state?

It depends on your new state's requirements. Check your new state's DMV website to see whether testing is required for your vehicle. If it is, you typically must test before you register your vehicle in that state. If you moved from a testing state to a non-testing state, you no longer need to test.

What if I fail emissions testing twice?

Most states allow you to retest as many times as needed within the grace period (usually 30 to 60 days). If you cannot pass after multiple attempts, some states offer a waiver or extended important date if you can show you have spent money on repairs. Contact your state's DMV or environmental quality agency to ask about waiver options.

Can I test my vehicle early?

Yes. Most states allow you to test your vehicle before your current test expires. The new test result will extend your testing important date from the date of the new test. This is useful if you are planning to sell your vehicle or want to renew your registration early.

Is emissions testing the same as a safety inspection?

No. Emissions testing checks whether your vehicle's exhaust meets pollution limits. A safety inspection checks brakes, lights, tires, and steering. Some states require both; some require only one; some require neither. Check your state's DMV website to see which inspections explore to you.

What if my vehicle has a check engine light on?

Most states will fail your vehicle if the check engine light is on, even if the underlying problem is minor. You must have the problem diagnosed and repaired, then clear the light before retesting. Many auto parts stores will scan the code for free to help you understand what needs to be fixed.