Not every state requires an emissions test or smog check to register your vehicle. In fact, roughly one-third of U.S. states have no routine emissions testing requirement for passenger cars and light trucks. Some never had programs at all. Others ended testing after meeting federal air quality standards. A few more are actively phasing out their programs right now. If you are moving to a new state, buying a car across state lines, or just curious whether your state might drop its testing requirement, this article breaks down where things stand in 2025. We cover which states currently have no emissions testing, which ones recently ended their programs, and which are scheduled to phase out testing soon. Keep in mind that even states without emissions programs may still require safety inspections or enforce federal anti-tampering rules. And within states that do test, requirements often apply only to specific metro areas, not the entire state. Check your state page for the details that apply to your registration address.
How Many States Require Emissions Testing?
Roughly two-thirds of U.S. states plus Washington D.C. run some kind of emissions or inspection and maintenance program for light-duty vehicles. The rest do not require a routine emissions or smog check for most passenger vehicles at registration. But even in states with programs, testing is often limited to specific metro areas or counties that have been designated as non-attainment zones under the federal Clean Air Act. These are areas that have not met federal standards for ozone, carbon monoxide, or other pollutants. Outside those designated zones, drivers in the same state may not need to test at all. Common test types include OBD-II plug-in checks for 1996 and newer vehicles, tailpipe or dynamometer tests for older vehicles, and opacity or snap-acceleration tests for diesels. When we say a state has no emissions testing, we mean it does not require periodic emissions checks for passenger cars and light trucks as a condition for registration. These states may still have safety inspections, VIN or theft inspections, and federal rules against tampering with emissions equipment. Removing a catalytic converter is still illegal even if your state does not test.
States With No Emissions Testing Requirements
States without routine passenger-vehicle emissions testing are concentrated in the Southeast, Great Plains, Midwest, and parts of the Mountain West. These states typically rely only on safety or title inspections, not smog checks. Examples include Alabama, Alaska, Arkansas, Florida, Iowa, Kansas, Kentucky, Michigan, Minnesota, Mississippi, Montana, Nebraska, North Dakota, Oklahoma, South Dakota, and Wyoming. Florida ended its emissions program back in 2000. Alaska eliminated testing in Anchorage and Fairbanks years ago. Michigan and Minnesota both previously ran emissions programs in selected metro areas but no longer require testing for passenger vehicles. In these states, you can register a vehicle without providing proof of a passing emissions test. However, you may still need to pass a safety inspection depending on the state, and federal anti-tampering laws still apply. If you are moving to one of these states from a testing state, you will not need to worry about emissions for your next registration renewal. Check your destination state page for any safety inspection requirements that might still apply.
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States That Recently Ended Emissions Testing
Several states have ended their emissions programs in recent years after demonstrating sustained compliance with federal air quality standards. Washington ended its Vehicle Emissions Check program on December 31, 2019, after nearly 40 years of operation. The state Department of Ecology concluded that newer, cleaner vehicles combined with other air quality measures made the program no longer necessary. As of 2020, no emissions inspection is required to register passenger vehicles in Washington. Tennessee ended testing in six counties, including Davidson County (Nashville) and Shelby County (Memphis), on January 14, 2022. The decision came after EPA approval based on sustained compliance with federal ozone standards and cleaner vehicle fleets in those areas. Since 2022, no county in Tennessee requires a routine emissions test for registration. Earlier program terminations include Alaska, Minnesota, Michigan, and Idaho, all of which ended localized urban programs as air quality improved over time. The pattern is consistent: once a region meets federal air quality standards and maintains them, states can submit data to justify ending their inspection and maintenance programs. EPA must approve before a state can officially stop testing.
States Phasing Out Emissions Testing Soon
Some states are actively working to end their emissions programs. New Hampshire has announced plans to end its OBD-II emissions inspection requirement for most passenger vehicles effective January 31, 2026. The state will keep its safety inspection but drop the emissions portion. Until that date, annual safety plus emissions inspections remain required for vehicles registered in New Hampshire. This makes New Hampshire a clear example of a state in the phasing-out process right now. More broadly, EPA guidance explicitly allows states to modify or discontinue emissions programs once long-term air quality goals are met, provided they demonstrate that air quality will not worsen without testing. Many state legislatures periodically introduce bills to reduce the number of counties covered, extend new-vehicle exemptions, switch from tailpipe to OBD-only testing, or eliminate programs entirely in certain areas. Just because one state ended its program does not mean others will automatically follow. EPA approval and air quality data drive the decision. States must show that ending testing will not cause pollution levels to rise above federal limits. Watch for announcements from your state environmental agency if you are hoping for a change.
How to Check If Your State Requires Emissions Testing
The best way to confirm your requirements is to check your state's official DMV or environmental agency website. Search for your state name plus emissions testing, smog check, or inspection and maintenance. Official pages are usually found on DMV, BMV, or MVD domains, or on state environmental agency sites. Many states with partial programs offer ZIP code or county lookup tools where you enter your registration address to see if you are in a testing area. If your county or ZIP is inside a vehicle emissions control area, you will need a test. If it is outside, you usually will not. When checking, verify whether any emissions test is required for new registrations, renewals, or title transfers. Check which vehicle types are covered, including gas, diesel, hybrid, EV, and heavy-duty vehicles. Look at the testing frequency, whether annual or biennial, and any model-year exemptions for newer vehicles. Once you confirm you need a test, use our state and city directory to find approved testing stations near you. Each state page in this directory includes links to official resources, program details, and station listings organized by city.
Key Takeaways
- About one-third of U.S. states have no routine emissions testing requirement for passenger vehicles.
- States without testing are concentrated in the Southeast, Great Plains, Midwest, and Mountain West.
- Washington ended testing in 2019 and Tennessee ended testing in 2022 after meeting air quality standards.
- New Hampshire plans to end emissions testing on January 31, 2026, while keeping safety inspections.
- Even states without emissions programs still enforce federal anti-tampering rules on emissions equipment.
- Check your state's official DMV or environmental agency site to confirm your specific requirements.
Related Reading
You may also want to read guides on what an emissions test actually is, how often testing is required in states with programs, what happens if you fail, and emissions requirements when moving to a new state. Use our state directory to see the specific rules for your registration address.
