When your smog check is due depends on your vehicle's age and your state's rules
Most states require a smog check every two years, but some require it every year, and a few don't require it at all. California, for instance, requires smog checks every two years for most vehicles, but every year for vehicles over 8 years old in certain counties. The frequency also depends on whether your vehicle is new, used, diesel, or electric — and whether you live in an area with stricter air quality standards.
Your registration renewal notice will tell you whether a smog check is required that year. If your state requires one, you cannot renew your registration without proof of a passing test. The test itself checks your vehicle's emissions system to make sure it meets state standards.
Key Takeaways
- Most states require smog checks every two years, though some require them annually and a few have no requirement at all.
- Your vehicle registration renewal notice will specify whether you need a smog check that year — do not guess based on last time.
- New vehicles are usually exempt for the first four to six years, depending on your state.
- You must pass the smog check before you can renew your registration, so plan to test at least a few weeks before your registration expires.
- Electric vehicles and some hybrid models are exempt from smog checks in most states because they produce no tailpipe emissions.
How to find out when your smog check is due
The simplest way is to look at your vehicle registration renewal notice. Your state's DMV or equivalent agency mails this notice 30 to 60 days before your registration expires. The notice will clearly state whether a smog check is required that year.
If you have lost the notice or want to check online, visit your state's DMV website and enter your vehicle's license plate or VIN. Most states have a tool that shows your registration status and whether a smog check is required. You can also call your local DMV office and provide your plate number — they will tell you on the spot.
Do not assume the requirement is the same every year. Some states alternate years, and some require checks more frequently for older vehicles. Checking each time you renew is the only reliable way to know.
States with different smog check schedules
California requires smog checks every two years for vehicles model year 1976 and newer, with a few exceptions. Vehicles over 8 years old in high-pollution areas may need annual checks. New vehicles are exempt for the first six years.
New York requires smog checks every two years for most vehicles, but every year for vehicles over 25 years old. New vehicles are exempt for the first three years.
Texas requires smog checks every two years in certain counties with air quality concerns, but not statewide. If you live in a county that requires them, your registration notice will say so. Many rural Texas counties have no requirement.
Several states — including Florida, Georgia, and most of the Midwest — have no statewide smog check requirement at all. However, individual counties or cities within those states may have local requirements, so check your local government website if you are unsure.
When new and used vehicles are exempt
New vehicles are typically exempt from smog checks for their first four to six years, depending on your state. This is because new vehicles are built to strict emissions standards and are unlikely to fail. Your registration notice will tell you when your vehicle becomes subject to testing.
Vehicles that are very old — usually 30 years or older — are sometimes exempt in states that do require smog checks. The reasoning is that classic or antique vehicles are rarely driven and are not a significant source of pollution. Check your state's DMV website to see if your older vehicle qualifies for an exemption.
Electric vehicles and plug-in hybrids are exempt in all states that require smog checks, because they produce no tailpipe emissions. Conventional hybrids are not automatically exempt — they still have a gas engine and must pass if your state requires it.
What happens if you miss your smog check important date
If your registration expires without a passing smog check, you cannot legally drive the vehicle. Driving with expired registration can result in a fine, and if you are stopped, you may be cited for both the expired registration and the missing smog check.
You can still get a smog check after your registration has expired — the test itself is not time-limited. However, you cannot renew your registration until you have a passing result. Once you pass, take the certificate to your DMV office or submit it online, and your registration will be renewed.
If your vehicle fails the smog check, you have a set period — usually 30 days — to repair it and retest. Some states allow one free retest if you fail. Check your state's rules on the DMV website or ask the testing station what your options are.
Planning ahead to avoid registration delays
Schedule your smog check at least three to four weeks before your registration expires. This gives you time to get the test done, receive the results, and submit them to the DMV before the important date. If you fail, you will have time to make repairs and retest.
Find a testing station near you by searching your state's DMV website — most states maintain a list of certified stations. Call ahead to ask about wait times. During peak renewal periods (often late in the month), testing stations can be busy, and you may wait several days for an appointment.
Keep your smog check certificate in a safe place. You will need to show it to the DMV when you renew your registration, either in person or by mail. Some states allow you to submit it online through your DMV account.
What to do if your state has no smog check requirement
If you live in a state with no statewide smog check requirement, you still need to renew your vehicle registration on schedule. Your renewal notice will not mention a smog check, and you can renew without one.
However, if you move to a state that does require smog checks, you will need to pass one before you can register your vehicle there. Plan for this if you are relocating. Some states allow a grace period of 30 to 60 days after you move to get your vehicle tested and registered under the new state's rules.
Frequently Asked Questions
Do I need a smog check if I just bought a used car?
Not when ready. You have a grace period — usually 30 to 60 days — to register the vehicle in your name. Once you register it, your first smog check will be due based on your state's schedule and the vehicle's age. Your registration notice will tell you when it is due.
Can I get a smog check before my registration expires?
Yes. You can test up to 90 days before your registration expires in most states. This is useful if you want to get it done early and avoid the rush. The test result will be valid when you renew your registration, as long as you renew within the 90-day window.
What if I drive a diesel truck or commercial vehicle?
Diesel vehicles have different testing requirements in most states. Some states exempt light-duty diesels from smog checks, while others require them. Commercial vehicles may have separate schedules. Check your state's DMV website or call your local office to find out what applies to your vehicle type.
How much does a smog check cost?
Smog check costs vary by state and testing station, typically ranging from $30 to $70 for a basic test. Some stations charge more for additional services or if your vehicle fails and needs a retest. Call ahead to ask about pricing before you schedule.
Can I renew my registration without a smog check if I am out of state?
No. If your state requires a smog check, you must have a passing result before you renew your registration, even if you are temporarily out of state. You will need to return to your home state or find a certified testing station in another state that can test your vehicle to your home state's standards — this is rare and usually not possible.