California requires a smog test every two years for most vehicles, or every year if your car is older or has failed before
Your smog test schedule depends on your vehicle's age and whether it has passed before. Most cars registered in California need a smog inspection every two years. Vehicles model year 1975 and older, plus any car that failed its last test, must be tested every year. If you drive a vehicle model year 2000 or newer with a clean history, you may not need to test at all — California exempts many newer cars from smog requirements.
The California Department of Consumer Affairs runs the smog program through licensed testing stations. You cannot choose when to test; your renewal notice from the Department of Motor Vehicles will tell you whether your vehicle needs one this year. Testing is required before you can renew your registration, and you must pass before the DMV will issue new tags.
Key Takeaways
- Most California vehicles need a smog test every two years, but your DMV renewal notice will specify whether your car needs one this year.
- Cars model year 1975 and older, plus any vehicle that previously failed, must test every year instead of every two years.
- Vehicles model year 2000 and newer may be exempt from smog testing entirely, depending on the specific year and your vehicle's history.
- You must pass the smog test before the DMV will renew your registration, so plan to test at least two weeks before your renewal important date.
- A smog test costs between $30 and $50 at a licensed station and takes about 10 to 15 minutes.
How to find your vehicle's smog test requirement
The DMV renewal notice you receive in the mail will state whether your vehicle requires a smog test. Look for the line that says "Smog Check Required" or "Smog Check Not Required." If it says required, you must obtain a passing test before you can renew your registration online or at a DMV office.
You can also check your vehicle's smog requirement on the California DMV website by entering your license plate number. The site will tell you whether your car is exempt, needs testing every two years, or needs testing every year. If you are unsure whether your vehicle qualifies for the smog exemption for newer cars, the DMV lookup tool will clarify this before you pay for an unnecessary test.
When your vehicle must test every year instead of every two years
Vehicles model year 1975 and older must test every year, as do any cars that failed their most recent smog inspection. If your car failed before, you will see "Annual Smog Check Required" on your renewal notice. This means you cannot wait two years between tests — you must test again within 12 months of your last test date.
Diesel vehicles also follow different rules than gasoline cars. Heavy-duty diesel trucks and buses have separate smog requirements that may differ from standard passenger vehicle schedules. If you own a diesel vehicle, check your renewal notice or the DMV website, as the testing frequency and location may not be the same as a gasoline car.
Vehicles that do not need to test at all
California exempts many newer vehicles from smog testing. Cars model year 2000 and newer that have never failed a smog test are typically exempt. The exact cutoff year can shift slightly, so check your renewal notice or the DMV website to confirm whether your specific vehicle is exempt.
Electric vehicles and hydrogen fuel cell vehicles are also exempt from smog testing. If you own one of these vehicles, you will not see a smog requirement on your renewal notice. Hybrid vehicles that run on gasoline are not automatically exempt and may still need to test depending on their model year.
What happens if you miss your smog test important date
If your renewal notice requires a smog test and you do not obtain one before your registration expires, you cannot legally renew your registration. The DMV will not issue new tags until you submit proof of a passing smog test. Driving with expired tags is a violation and can result in a fine.
If you have already let your registration expire, you can still get a smog test and then renew your registration. However, you should do this as soon as possible to avoid driving illegally. Some smog stations can issue a test report the same day, which you can then take to the DMV or submit online to complete your renewal.
How to prepare your vehicle for a smog test
Before you take your car to a smog station, make sure the check engine light is not on. If the light is illuminated, the vehicle will fail the test automatically. Have a mechanic diagnose and repair the issue before you test. Common reasons for a check engine light include a loose gas cap, a faulty oxygen sensor, or a catalytic converter problem.
Warm up your engine for at least 20 minutes before the test. A cold engine can produce higher emissions and cause a failure. Drive on the highway or at steady speeds to fully warm the engine, then head to the testing station. Make sure your vehicle has enough fuel in the tank — most stations require at least a quarter tank to run the test properly.
Finding a licensed smog testing station
You must use a station licensed by the California Department of Consumer Affairs. Not all repair shops or gas stations perform smog tests, so verify that the location you choose is licensed before you arrive. The California Bureau of Automotive Repair maintains a searchable list of licensed smog stations on its website, organized by county and city.
Smog tests typically cost between $30 and $50, though prices vary by station and region. Call ahead to confirm the price and whether you need an appointment. Most tests take 10 to 15 minutes. Once you pass, the station will issue a smog test report that you can submit to the DMV to complete your registration renewal.
Renewing your registration after you pass the smog test
After you receive your passing smog test report, you have 30 days to submit it to the DMV and renew your registration. You can renew online through the DMV website if you have your smog test report number and renewal notice. You can also mail the report to the DMV or bring it to a DMV office in person.
Online renewal is the fastest option — you can complete it in minutes and receive your new registration tags by mail within two weeks. If you renew in person at a DMV office, you can sometimes receive temporary tags the same day. Plan to renew at least two weeks before your current registration expires to may support your new tags arrive on time.
Frequently Asked Questions
What if my car fails the smog test?
If your vehicle fails, the smog station will provide a report explaining which emissions standards it did not meet. You will need to have a mechanic repair the problem, then return to a smog station for a retest. You have 30 days from the date of the failed test to retest at no additional charge at the same station.
Can I test early, before my renewal notice says I need to?
Yes, you can test early if you want to renew your registration ahead of schedule. The test report is valid for 30 days, so plan your test timing so the report does not expire before you submit it to the DMV. Testing early does not change when your next test will be due — your two-year or one-year cycle resets from the date of the early test.
Do I need a smog test if I just bought a used car?
If you recently purchased a used car and transferred the registration into your name, you will follow the same smog schedule as any other vehicle. Check your new renewal notice or the DMV website to see whether your vehicle requires a test. The purchase date does not affect the requirement — only the vehicle's model year and test history matter.
What if I move out of California — do I still need to smog my car?
If you move out of California and register your vehicle in another state, you no longer need California smog tests. However, you must complete your California registration renewal and obtain a passing smog test before you can legally transfer your vehicle out of state. Some other states have their own emissions testing requirements, so check your new state's rules.
Are motorcycles and RVs subject to smog testing?
Motorcycles are generally exempt from California smog testing. Recreational vehicles and motorhomes have different requirements depending on their model year and fuel type. Check your renewal notice or the DMV website to confirm whether your specific vehicle type requires testing, as the rules vary.