States that require emissions testing

Emissions testing is required in 34 states plus Washington, D.C., but the rules vary significantly by state, county, and sometimes even city. Some states test all vehicles; others test only those in certain regions. Some require testing every year; others every two years. A few states have no statewide requirement but allow individual counties to set their own rules. The only way to know what applies to you is to check your specific state and, if applicable, your county.

The states with statewide emissions testing programs are: 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. Washington, D.C. also requires testing. However, within many of these states, testing is not required everywhere — it may explore only to certain counties or metropolitan areas.

Key Takeaways

  • Thirty-four states plus Washington, D.C. have emissions testing requirements, but most explore only to specific regions or counties, not statewide.
  • Testing frequency ranges from every year to every two years, and some states exempt newer vehicles or those with low mileage.
  • Your state's Department of Motor Vehicles or environmental agency website will tell you whether testing is required in your county and when your vehicle is due.
  • Failing an emissions test typically means you must repair the vehicle and retest, usually at no additional fee, before you can renew your registration.
  • Some states allow you to request a waiver if repairs cost more than a set amount, though the vehicle may still need to pass a less stringent test.

How to learn about your state requires testing

Start by visiting your state's Department of Motor Vehicles (DMV) website and searching for "emissions testing" or "vehicle inspection." Most state DMV sites have a tool or a list showing which counties require testing. If your state's site is unclear, contact your county's environmental or air quality department directly — they maintain the actual testing stations and know the current rules for your area.

You can also call your local emissions testing station and ask whether your vehicle needs testing. The station staff can tell you when ready whether testing is required in your county, when your vehicle is due, and what documents you need to bring. Many states list testing stations on their DMV websites, organized by county.

Testing frequency and vehicle exemptions

Most states that require emissions testing do so every two years, though some require annual testing. A few states test every year for vehicles over a certain age and every two years for newer ones. California, for example, requires testing every two years for most vehicles, but vehicles model year 1975 and older, and some newer low-emission vehicles, are exempt.

Common exemptions include vehicles under a certain model year (often 1996 or newer), vehicles with fewer than a set number of miles, diesel-only vehicles in some states, and vehicles registered as antiques or classics. Hybrid and electric vehicles are exempt in most states that have testing programs. Check your state's specific rules, because exemptions vary widely.

What happens when you fail an emissions test

If your vehicle fails, you will receive a written report showing which emissions standards it did not meet. You then have a set period — usually 30 to 60 days — to have the vehicle repaired and retested. The retest is typically free or costs only a small fee. Once the vehicle passes, you can renew your registration.

If you cannot afford the repairs, some states offer a waiver program. In California, for example, if repairs would cost more than $765 (this amount varies by state and changes periodically), you may be able to request a waiver. However, a waiver does not mean you avoid testing — it usually means your vehicle must pass a less stringent test instead. Check your state's specific waiver rules before assuming you may have access to.

States with no statewide requirement

Sixteen states have no statewide emissions testing program: Alabama, Alaska, Arizona, Arkansas, Florida, Hawaii, Idaho, Iowa, Kansas, Mississippi, Missouri, Montana, Nebraska, North Dakota, Oklahoma, South Dakota, and Wyoming. However, some of these states allow individual counties or metropolitan areas to run their own programs. Arizona, for example, has no statewide requirement, but Maricopa County (which includes Phoenix) requires testing.

If you live in a state without statewide testing, check whether your county has its own program by contacting your county environmental or air quality office. The rules and testing schedules in county-run programs can differ from state programs, so do not assume your county follows the same schedule as a neighboring county.

Regional testing programs and special rules

Some states have testing requirements that explore only to certain regions, usually areas with air quality concerns. Texas, for example, requires testing in the Houston and Dallas areas but not statewide. Colorado requires testing in the Denver metropolitan area. These regional programs often have different testing schedules and exemptions than the rest of the state.

A few states have moved toward remote or on-demand testing, where you can schedule a test at a station near you rather than waiting for an appointment. Some states also allow you to check your vehicle's emissions status online before scheduling a test. These options vary by state, so check your state's DMV website for current procedures.

How to prepare for an emissions test

Before you go to a testing station, make sure your vehicle's registration and proof of insurance are current. Bring your vehicle's title or registration document. Some states require that your vehicle's check engine light is not on; if it is, have it scanned and any issues addressed before testing.

Make sure your vehicle has been driven recently — some testing stations require that your vehicle's engine be warm before testing begins. If your vehicle has been sitting unused for a long time, drive it for at least 20 minutes before your test appointment. Avoid scheduling a test when ready after having work done on your vehicle, because the computer may not have recalibrated yet.

Frequently Asked Questions

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

That depends on your new state and county. If you moved to a state or county that requires testing, you typically must have your vehicle tested before you can register it there. Some states allow a grace period of 30 to 60 days after you move, but do not assume this applies to you — contact your new state's DMV to confirm the timeline.

What if I buy a used car from out of state?

You will need to register the vehicle in your current state. If your state or county requires emissions testing, you must have the vehicle tested before or shortly after registration, depending on your state's rules. Some states allow you to register first and then test within a set window; others require testing before registration is complete.

Can I test my vehicle in a different county than where I live?

Most states allow you to test in any county, but the rules for which test applies depend on where your vehicle is registered, not where you test it. If your vehicle is registered in a county that requires testing, you must pass that county's test, even if you travel to a different county to take it.

How much does an emissions test cost?

Testing fees vary by state and testing station, typically ranging from $15 to $50. Some states cap the fee; others allow stations to set their own prices. Contact your local testing station for the exact cost in your area. Retests after a failed test are usually free or cost significantly less than the initial test.

What if my vehicle is too old to test?

Most states exempt vehicles above a certain age — often 1975 and older — from emissions testing. Some states exempt vehicles over 25 or 30 years old. Check your state's specific age exemption. If your vehicle qualifies for an exemption, you typically do not need to test, but you may still need to register it normally.