What California's Smog Check Is and When You Need One

A smog check is an emissions test that California requires for most vehicles before you can renew your registration. The test measures whether your car's exhaust meets state air quality standards. You do not get the smog check through the DMV itself — you go to a licensed smog check station, get tested, and if you pass, the station sends the results electronically to the DMV.

Whether you need one depends on your vehicle's age and type. Most cars and light trucks registered in California need a smog check every two years when you renew. Newer vehicles — typically those from the current model year and the four years before — are exempt for their first six years of registration. Diesel vehicles, motorcycles, and vehicles over 1975 have different rules.

If your smog check is not on file with the DMV when you try to renew your registration, the DMV will not issue you a new registration sticker. You cannot legally drive without current registration, so the smog check is a hard requirement, not optional.

Key Takeaways

  • Most California vehicles need a smog check every two years, but you get it from a licensed smog check station, not the DMV.
  • New vehicles are exempt from smog checks for their first six years of registration in California.
  • The smog check station reports your results to the DMV electronically, so you do not need to bring paperwork to the DMV yourself.
  • If you fail the smog check, you have 30 days to repair your vehicle and retest at no additional charge at the same station.
  • You can renew your registration online, by mail, or in person at the DMV, but only after your smog check passes and appears in the system.

Which Vehicles Need a Smog Check in California

Passenger cars, SUVs, and light trucks registered in California need a smog check every two years during registration renewal if they are more than six years old. The six-year exemption starts from the vehicle's model year, not the year you bought it. A 2019 model-year car, for example, would not need a smog check until 2025.

Diesel vehicles have a separate schedule: they need a smog check every two years starting in their ninth year of registration. Motorcycles, motorhomes, and vehicles registered before 1975 do not need smog checks. Vehicles with a salvage title or that are registered as non-operational also do not require one.

If you move to California from another state and register your vehicle here for the first time, you will need a smog check unless your vehicle is within the six-year exemption window. The smog check requirement is tied to California registration, not to how long you have owned the car.

How to Find a Smog Check Station and What to Bring

You can find licensed smog check stations through the California Bureau of Automotive Repair (BAR) website at bar.ca.gov. Search by zip code or city to see stations near you. Not all repair shops do smog checks, so verify before you go. The station must display a BAR license number on the window.

Bring your vehicle registration and a valid photo ID. The smog check technician will run your vehicle's identification number (VIN) through the system to confirm your vehicle is due for a test and to pull up your vehicle's history. The test itself takes 10 to 30 minutes and costs between $30 and $80 depending on the station and your vehicle type.

You do not need an appointment at most stations, but calling ahead can save you wait time. Some stations are busier during certain times of year — late in the registration renewal period is typically slower than early in the cycle.

What Happens If You Pass or Fail the Smog Check

If you pass, the smog check station sends your results to the DMV electronically within one business day. You will see a confirmation number at the station. You can then renew your registration online, by mail, or in person at the DMV without bringing any smog check paperwork — the DMV pulls the results from its system.

If you fail, the station gives 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 return to the same station for a retest at no charge. The station will waive the retest fee if you come back within that window. After 30 days, you must pay the full test fee again.

If your vehicle fails a second time, you can still retest, but you may want to have a mechanic diagnose the problem before the next attempt. Common failures involve the oxygen sensor, catalytic converter, or fuel system. If repairs are expensive, you may want to get a second opinion from another shop before proceeding.

Timing Your Smog Check With DMV Registration Renewal

You can get a smog check anytime during your registration renewal cycle, but it makes sense to do it early — at least two weeks before your registration expires. This gives you time to fix any problems if you fail and still renew on time.

Your registration renewal notice from the DMV will show your renewal due date. You can renew up to 60 days before that date. If you wait until the last week and fail the smog check, you will be cutting it close to get repairs done and retested.

If your registration expires before your smog check passes, you are driving without valid registration, which is a violation. If you know you will need repairs, start the smog check process at least 45 days before your renewal date to leave room for a retest and any fixes.

Renewing Your Registration After a Passing Smog Check

Once your smog check passes and the station reports it to the DMV, you can renew your registration through any of three methods: online at dmv.ca.gov, by mail using the renewal notice the DMV sent you, or in person at a DMV office. The smog check result is automatically in the system, so you do not need to bring anything related to the test.

Online renewal is the fastest — you can complete it in minutes and your registration sticker will arrive by mail within two weeks. Mail renewal takes about three weeks. In-person renewal at the DMV is when ready if you bring your renewal notice and a valid ID, but you may wait in line.

The registration renewal fee varies by vehicle type and weight but typically ranges from $200 to $400. You can pay by credit card, debit card, or check. If you renew online or by mail, you will receive a temporary registration document by email or mail that you can print and display until your sticker arrives.

What to Do If You Cannot Pass the Smog Check

If your vehicle repeatedly fails the smog check despite repairs, you have a few options. First, get a second opinion from a different repair shop — sometimes the first diagnosis is incomplete. Second, check whether your vehicle qualifies for the Smog Check Referee Program, which allows you to have a referee test your vehicle if you believe the original test was wrong.

Third, look into whether your vehicle qualifies for the Consumer information Program (CAP) or the Gross Polluter Abatement Program. CAP can help pay for repairs if your vehicle is an older model and you meet income limits. Gross Polluter Abatement may allow you to retire a vehicle that cannot pass and receive a rebate toward a cleaner one.

If none of these options work and your vehicle cannot pass, you cannot legally register it in California. You would need to sell it, move it out of state, or retire it through a vehicle recycling program. Contact the BAR at bar.ca.gov or call 1-800-622-7233 for information about these programs in your situation.

Frequently Asked Questions

Can I renew my registration before I get a smog check?

No. The DMV will not issue a new registration sticker until a passing smog check is on file. You can start the renewal process online or by mail, but it will not complete until the smog check result is in the system. If you try to renew in person at the DMV without a smog check, the clerk will tell you to get tested first.

What if I move out of California after I get a smog check?

A California smog check is only valid for California registration. If you move to another state, you will follow that state's emissions testing rules, which may be different or nonexistent. You do not need to do anything with your California smog check result — it stays on file with the California DMV.

Do I need a smog check if I buy a used car from a dealer?

Yes, unless the vehicle is within its six-year exemption window. A dealer will have transferred the registration to you, but you still need a smog check when you renew. The dealer does not do this for you. You are responsible for getting the smog check before your first registration renewal as the new owner.

How long does a smog check result stay valid?

A passing smog check is valid for 30 days from the test date. You must renew your registration within that window. If 30 days pass without a renewal, you will need a new smog check. If you renew your registration on time, the result is locked in and you do not need another test until your next renewal cycle two years later.

Can I get a smog check for a vehicle that is not yet registered in California?

No. The smog check station runs your VIN through the system and confirms you have a California registration due for renewal. If your vehicle is not yet registered in California, you cannot get a smog check. You must register the vehicle first, then get the smog check before renewing.