How to Get a Smog Check (CA)

A clear guide for getting and passing a smog check in California

Co-authored by Tom Eisenberg and Christopher M. Osborne, PhD

Last Updated: March 20, 2024 References

In the United States, both federal and state governments have tightened automobile emissions standards because of increasing smog and air pollution. California, for instance, has its longstanding and rigorous “smog check” program for most vehicles. If you live in the Golden State, and have an automobile that’s more than six years old, you’ll probably have to pass the smog check requirements at least every two years in order to register or sell your vehicle.

Part 1

Part 1 of 2:

Taking Your Vehicle in for a Smog Check

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1
Figure out if you need to get a smog check. Practically every passenger vehicle in California that was manufactured between 1976 and six years ago (e.g., 2011 models in 2017) needs to pass a smog check every two years.
- If you’re a registered vehicle owner in the state, check for the phrase “SMOG Certification Required” on your DMV Registration Renewal Notice.
- Certain ZIP codes in El Dorado, Placer, Riverside, San Bernardino, San Diego, and Sonoma Counties are excluded from smog checks.
- If you're new to California, you typically must get a smog check within twenty days of arrival and before you register the vehicle.^{[1]
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- If you want to sell an eligible vehicle in-state (other than to close family, like children or siblings), it must have passed a smog check within the past 90 days.
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Find a licensed smog check station. Search the state's Bureau of Automotive Repair webpage for licensed smog check stations near you. You can also call the BAR at (800) 952-5210. Contact eligible stations directly to compare prices and make an appointment.
- If your registration renewal notice reads “SMOG Certification Required at a STAR Station,” you must make an appointment at an inspection/service station with STAR licensure. If you're unsure, contact the BAR for the proper test for your vehicle.
- Generally speaking, vehicles with especially high emissions levels (e.g., a giant “gas guzzler”) must undergo the STAR inspection.^{[2]
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Bring proof of vehicle registration and a form of payment to the test. If you have a Registration Renewal Notice, bring that. Otherwise, bring your current vehicle registration. This is all you need to have with you when you take your vehicle to its smog check at an authorized station.^{[3]
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- There is no set price for a smog check; licensed stations can charge any amount they see fit. Shop around a bit before choosing a station.^{[4]
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Pay and be on your way if your vehicle passes. Smog check results are automatically and electronically forwarded to the appropriate government agency. That means you don’t need to get anything signed, get a sticker, etc. You may, however, want to keep the paperwork and your receipt just in case there is a transmission error.
- You’ll only get a certificate if you’ve passed an initial smog check after moving to California. If so, bring it with you when you register your vehicle.^{[5]
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- Remember, though, that you still need to complete (and pay for) the rest of the registration renewal process.

Part 2

Part 2 of 2:

Making Sure Your Vehicle Passes

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1
Pay to have the vehicle repaired before the test. If you’re confident your vehicle won’t pass a smog check, getting repairs beforehand will save you time (and possibly money) versus failing the test, fixing the car, and then taking the test again.^{[6]
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- Some stations may offer an unofficial pre-inspection at a reduced price.
- An unresolved “Check Engine” light, which often results from a faulty oxygen sensor, is basically an automatic cause for failure of a smog check.
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Do any regular maintenance two weeks before the test. Recurring vehicle maintenance usually involves disconnecting the battery (which in turn resets the computer). The car needs two weeks of driving to complete the diagnostics needed for the smog check.^{[7]
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- Get the oil changed, since dirty oil can release pollutants that could trigger a test failure.
- Try to drive the car at highway speeds frequently during the two weeks before the test; this will help burn off oil and gas residues from the catalytic converter.
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Give the vehicle a tune-up shortly before the test. Check and refill any low coolant levels, and fill the gas tank. These measures will keep the engine running cooler and reduce fuel vapors during the test.^{[8]
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- Make sure the tires are properly inflated. The smog check includes a dynamometer test (running the car at high speeds on rollers), and this easy fix will cut down on how hard your engine needs to work (and thus emissions).
- Use a fuel additive, especially if you have an older vehicle that may have clogged fuel injectors.
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Pay for repairs after a first failed test. Following a failed smog check, your easiest (but not necessarily cheapest) option is to have it repaired so that it will pass. If the inspection station is also authorized to do smog check-related repairs, you can have them done there, or take your car to another licensed repair facility.
- After repairs, you’ll have to pay for another smog check — and hopefully pass it. If your vehicle is in the STAR program, you must have the repeat smog check done at a STAR-licensed station.
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Get a second opinion if you fail the initial smog check. You can make a formal appeal if you're convinced your car should have passed. There are authorized “Referee” stations situated throughout California, and you can make an appointment to have your car re-tested at one of these facilities.
- Call 1-800-622-7733 to find a Referee station.
- Referee stations do not do vehicle repairs — they will either pass your vehicle or give you a list of recommended repairs needed to achieve compliance.
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Apply for a repair waiver or financial assistance. If you meet certain income and expenditure criteria, you may be able to reduce the cost of making vehicle repairs to meet smog check requirements. There are two options available to California drivers:
- The Repair Cost Waiver may be available to you if you have made some repairs to your vehicle to improve its emissions levels, but cannot afford the additional repairs needed to pass the smog check. Visit http://www.asktheref.org/
- If you meet the income requirements, you can apply for a $500 discount towards emissions-related repairs through the Consumer Assistance Program.
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Retire your vehicle if paying for repairs is too costly. If, for instance, the cost for repairs exceeds what your old clunker of a car is worth, you can actually get paid to take it off the road permanently. The state’s Vehicle Retirement Program will pay you up to $1,500 to surrender the vehicle to an authorized agent for dismantling.
- Your vehicle must have failed a recent smog check to be eligible.

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Question

How often should I get a smog check?

Tom Eisenberg
Car Mechanic
Tom Eisenberg is the Owner and General Manager of West Coast Tires & Service in Los Angeles, California, a family-owned AAA-approved and certified auto shop. Tom has over 10 years of experience in the auto industry. Modern Tire Dealer Magazine voted his shop one of the Best 10 Operations in the Country.

Tom Eisenberg

Car Mechanic

Expert Answer

After an initial smog check, you should plan on getting one every 2 years after your car is 5 years old.

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How do smog tests work?

Tom Eisenberg
Car Mechanic
Tom Eisenberg is the Owner and General Manager of West Coast Tires & Service in Los Angeles, California, a family-owned AAA-approved and certified auto shop. Tom has over 10 years of experience in the auto industry. Modern Tire Dealer Magazine voted his shop one of the Best 10 Operations in the Country.

Tom Eisenberg

Car Mechanic

Expert Answer

Smog tests are performed by hooking a meter to your exhaust and your engine to make sure your catalytic converters, which are filters for your exhaust, are working.

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Note that several states in the U.S. have no emissions testing requirements. While the definition of what constitutes an emissions test or “smog check” can vary widely, only 31 of the 50 states have full or partial emissions inspection requirements.^{[9]
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You can quickly look up the wide variation in emissions testing standards among the fifty states in the U.S. For instance, although it’s not an official government site, DMV.org provides a gateway to testing requirements state to state.^{[10]
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Some states have county-by-country requirements. For instance, in Pennsylvania, only 25 of 67 counties have emissions testing, which is done annually alongside the statewide safety inspection.^{[11]
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