California requires a smog check every two years for most vehicles, with some exceptions based on age and type

In California, you need a smog check every two years if your vehicle is registered in the state and is model year 1975 or newer. The test must happen before your registration expires. If you buy a used vehicle, you need one within 90 days of purchase before you can register it. Vehicles model year 1974 and older, electric vehicles, and some other categories do not require smog checks at all.

The exact timing depends on when your registration was last renewed. Your registration renewal notice will show the expiration date — your smog check must be completed before that date. You cannot renew your registration without a passing smog check result on file with the California Department of Motor Vehicles (DMV).

Key Takeaways

  • Most California vehicles need a smog check every two years, timed to your registration expiration date.
  • New vehicle purchases require a smog check within 90 days before you can complete registration.
  • Vehicles model year 1974 and older, electric vehicles, and hydrogen fuel cell vehicles are exempt from smog checks.
  • You must pass the smog check before your registration expires, or the DMV will not renew your registration.
  • The smog check result is sent electronically to the DMV by the testing station, so you do not need to mail anything yourself.

When your registration expires and how to find your smog check due date

Your vehicle registration renewal notice arrives in the mail about 60 days before your registration expires. The notice shows the exact expiration date in large print. Your smog check must be completed and pass before that date.

If you have lost your renewal notice, you can find your registration expiration date by logging into the California DMV website with your driver's license number and vehicle identification number (VIN), or by calling the DMV at 1-800-777-0133. Some counties also allow you to check this information at your local DMV office.

Plan to get your smog check at least two weeks before your registration expires. Testing stations can be busy, especially near the expiration date, and if you fail the test you will need time to repair your vehicle and retest.

Vehicles that do not need a smog check

Not all registered vehicles in California require smog checks. Electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), and hydrogen fuel cell vehicles are permanently exempt. Vehicles model year 1974 and older are also exempt, as are some vehicles registered as classic cars or street rods under specific California programs.

Diesel vehicles have different rules than gasoline vehicles. Heavy-duty diesel trucks and some commercial diesel vehicles follow separate smog check schedules and may test less frequently. If you own a diesel vehicle, check your registration renewal notice or contact the DMV to confirm your specific requirement.

Vehicles registered as off-road only, motorcycles, and vehicles registered in other states do not need California smog checks. If you move to California from another state, you will need a smog check within 90 days of registering your vehicle here, regardless of when you last tested it.

What happens if you fail your smog check

If your vehicle fails the smog check, the testing station will give you a written report showing which emissions standards your vehicle did not meet. You have 30 days from the test date to repair your vehicle and retest at no additional fee at the same station. The retest is free even if you go to a different station, as long as you do it within 30 days.

If you cannot afford the repairs, California offers the Smog Check Repair information Program for vehicles that fail and cost more than a certain amount to fix. You can also explore for a Gross Polluter Abatement Program waiver if your vehicle repeatedly fails and repairs are too expensive. Contact your local air quality management district to learn about these programs in your area.

If your registration expires before you pass the smog check, you cannot legally drive your vehicle on public roads. You must complete repairs and pass the test before you can renew your registration.

Where to get a smog check and what to bring

You can get a smog check at any California-certified smog check station. These include independent smog shops, some auto repair shops, and some gas stations. You do not have to go to a specific brand or dealership. Search for "smog check stations near me" online or use the California Bureau of Automotive Repair (BAR) station locator on their website.

Bring your vehicle registration or renewal notice and a valid photo ID. The testing station will need your vehicle identification number (VIN) and current mileage. The test itself takes about 10 to 15 minutes. The station will send your results electronically to the DMV — you do not need to do anything else or mail any paperwork.

Smog check costs vary by station and region, typically ranging from $30 to $80 for a basic test. Some stations charge extra for vehicles that fail or for additional diagnostic work. Ask the station for their price before you start the test.

Smog check requirements for newly purchased used vehicles

When you buy a used vehicle in California, you have 90 days to complete a smog check before you can register it with the DMV. This applies even if the vehicle just passed a smog check at the dealership — you still need your own test on file. The 90-day window starts from the date of purchase, not from the date you receive your paperwork.

If you buy a vehicle from a private seller, you are responsible for getting the smog check. If you buy from a dealership, the dealer may offer to arrange it, but you can also get it done yourself at any certified station. Either way, the result must be submitted to the DMV before your registration is final.

If your 90 days expire before you pass the smog check, you cannot legally register the vehicle. You will need to retest and submit a new result to complete registration.

Smog check timing and registration renewal

Your smog check must be completed no more than 60 days before your registration expires. If you test too early, the result may not be valid for your renewal. The testing station will tell you the valid date range when you take the test.

You can renew your registration online, by mail, or in person at a DMV office. The DMV will not process your renewal until a passing smog check result is on file. Once you pass the test, the station sends the result to the DMV electronically, usually within one business day. You can then complete your registration renewal.

If you renew your registration before getting a smog check, your registration will be suspended until you pass the test and submit the result. It is faster to get the smog check first, then renew your registration.

Frequently Asked Questions

Can I get a smog check before my registration expires?

Yes, but only within 60 days of your expiration date. If you test earlier than that, the result will not be valid for your renewal. The testing station will tell you the valid date range when you take the test. Plan to test in the 60 days before your registration expires.

What if I move out of California — do I still need a smog check?

No. Once you register your vehicle in another state, you no longer need California smog checks. If you move back to California later, you will need a new smog check within 90 days of registering your vehicle here again.

Do I need a smog check if I only drive my car occasionally?

Yes. The requirement is based on your registration, not how often you drive. If your vehicle is registered in California and is model year 1975 or newer, you need a smog check every two years before your registration expires, regardless of mileage or how often you use it.

Can I get a smog check at a dealership instead of an independent station?

Yes. Dealerships can be certified smog check stations. However, they often charge more than independent shops. You can choose any certified station — you are not required to use the dealership where you bought the vehicle.

What if my vehicle is registered in California but I live out of state?

You still need a smog check every two years before your registration expires. You can get the test done at any California-certified station when you visit the state, or you can arrange for someone in California to take your vehicle to a station on your behalf. The result must be submitted to the DMV before your registration expires.