What California's Smog Check Is and Who Needs It

California's Smog Check is an emissions test that measures whether your vehicle's exhaust meets state air quality standards. Most vehicles registered in California must pass this test every two years, though some newer cars and certain vehicle types are exempt. The test itself takes about 10 minutes and costs between $30 and $50 depending on your location and vehicle type.

You need a Smog Check before you can renew your vehicle registration with the California Department of Motor Vehicles (DMV). If your registration expires and you have not passed the test, you cannot legally renew your plates. The state uses these tests to track which vehicles are contributing to air pollution and to identify problem areas across California's air basins.

Key Takeaways

  • Most California vehicles need a Smog Check every two years before DMV registration renewal, though the exact timing depends on your vehicle's model year and type.
  • You can only get tested at a California-licensed Smog Check station, which you can find through the Bureau of Automotive Repair's online station locator.
  • If your vehicle fails, you have 30 days to repair it and retest at no additional cost at the same station.
  • Vehicles model year 1975 and older, diesel trucks over 14,000 pounds, and some other categories do not require Smog Checks.
  • Your test results go directly to the DMV electronically, so you do not need to bring paperwork to the registration office.

Which Vehicles Are Required to Get Tested

Passenger cars, light-duty trucks, and SUVs registered in California generally need a Smog Check every two years. The requirement applies to vehicles model year 1976 and newer. If your vehicle is registered in a county that participates in the program — which includes most of California's populated areas — you will need to pass before renewal.

Some vehicles are permanently exempt. These include motorcycles, vehicles model year 1975 and older, diesel-powered vehicles over 14,000 pounds gross vehicle weight rating, and vehicles that have been registered as non-operational. Electric vehicles and hydrogen fuel cell vehicles are also exempt. If you are unsure whether your specific vehicle needs testing, the Bureau of Automotive Repair's website has a tool where you can enter your vehicle information.

New vehicles are exempt for their first six years of registration. After that, they follow the standard two-year test cycle. If you buy a used vehicle, you may need a Smog Check before you can register it in California, depending on when it was last registered and tested.

When Your Smog Check Is Due

Your Smog Check is due every two years, and the timing is tied to your vehicle registration renewal date. The DMV sends you a renewal notice about 60 days before your registration expires. That notice will tell you whether you need a Smog Check. You can get tested anytime during the 90 days before your registration expires, and the results will be valid for your renewal.

If you get tested more than 90 days before your registration expires, the test results will not be valid for that renewal cycle. You would need to test again closer to your renewal date. The test results themselves are valid for 30 days from the test date, so plan your testing window accordingly.

If your registration has already expired and you have not passed a Smog Check, you cannot legally drive the vehicle. You must get tested and pass before you can renew your registration with the DMV.

How to Find a Smog Check Station and Get Tested

You can only get a Smog Check at a station licensed by the Bureau of Automotive Repair. These are typically independent repair shops, gas stations, or dedicated testing facilities. To find one near you, visit the Bureau of Automotive Repair's online station locator at bar.ca.gov and search by your zip code or city. The locator shows you the station's address, phone number, hours, and whether they test your vehicle type.

Call ahead or check online to confirm the station is open and can test your vehicle. Bring your vehicle registration and a valid photo ID. The test itself involves connecting your vehicle to an emissions analyzer, which reads your exhaust gases. The technician will tell you when ready whether you passed or failed.

The test costs between $30 and $50. Some stations charge more for certain vehicle types, such as heavy-duty trucks or vehicles with special equipment. Cash, credit, and debit are typically accepted, but confirm payment methods when you call.

What Happens If Your Vehicle Fails the Test

If your vehicle fails the Smog Check, you have 30 days to repair the problem and retest. You do not pay for the retest — the station will test you again at no charge within that 30-day window. The failure notice will tell you which emissions systems failed, though it may not specify the exact repair needed.

Take the failure notice to a repair shop. The technician can use the failure code to diagnose what needs fixing. Common failures involve the oxygen sensor, catalytic converter, fuel cap, or engine control system. Repairs can range from $50 for a fuel cap to several hundred dollars for a catalytic converter, depending on your vehicle.

After repairs, return to the same Smog Check station within 30 days and ask for a retest. If you pass, the station reports your passing result to the DMV. If you fail again, you have another 30 days to repair and retest. If you do not retest within 30 days of the first failure, you will need to pay for a new test at a different station.

How Your Test Results Reach the DMV

When you pass your Smog Check, the testing station transmits your results electronically to the California DMV within one business day. You do not need to bring any paperwork to the DMV or print anything yourself. The DMV will see your passing test when you go to renew your registration online, by mail, or in person.

If you renew your registration online through the DMV website, the system will confirm that your Smog Check is on file before it processes your renewal. If you renew by mail or in person, the DMV will verify your test results in their system. You should keep your Smog Check receipt for your records, but you do not need to submit it with your registration renewal.

If there is a delay in the electronic transmission, the station can print you a receipt showing your passing result. If the DMV does not see your test results within a few days, contact the testing station to confirm they submitted it, or bring your receipt to the DMV office.

Frequently Asked Questions

Can I get a Smog Check before my registration expires?

Yes, but only within 90 days before your registration expires. If you test more than 90 days early, the results will not be valid for that renewal cycle. You can check your registration expiration date on your registration card or the DMV renewal notice.

What if I just moved to California and need to register my vehicle here?

If your vehicle is model year 1976 or newer and you are registering it in a Smog Check county, you will need a passing test before registration. Some vehicles may be exempt depending on their age and type. Check the Bureau of Automotive Repair website or call your local DMV office to confirm your vehicle's requirements.

Do I need a Smog Check if I am only renewing my registration, not buying a new vehicle?

Yes, if your vehicle is required to have one and your registration is expiring. The Smog Check requirement applies to all registration renewals for vehicles that are not exempt, not just to new purchases.

What if my vehicle is registered in another state but I drive it in California?

If your vehicle is registered out of state, you do not need a California Smog Check unless you are registering it in California. Once you register it here, you will need to pass a Smog Check before your first California registration renewal.

Can I drive my vehicle if my registration is expired but I have already scheduled a Smog Check?

No. You cannot legally drive a vehicle with expired registration, even if you have a Smog Check appointment scheduled. You must pass the test and renew your registration before you can legally operate the vehicle on public roads.