Although car ownership is almost a necessity in California, the state's smog laws and emissions requirements can be confusing and overwhelming, even for someone who has lived in California for many years.

If your car doesn’t pass a smog test, you have two choices. Fix it and have it retested, or sell it and use the funds to buy a new car. Is your car worth fixing? Click the button below to see how much your car is worth.

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What Are the Differences Between California and Federal Emissions Laws?

Emissions and smog laws are meant to reduce the amount of carbon monoxide, oxides of nitrogen (NOx), particulate matter (PM), formaldehyde, non-methane organic gases, and non-methane hydrocarbons that cars release into the air. Regulations usually measure emissions by grams per mile (g/mi).

The federal government, through the Environmental Protection Agency, has a set of standards that all vehicles in the country must follow. Besides helping the environment, these laws also can encourage better fuel economy. Although lawmakers are trying to make federal requirements more closely match California's requirements, California's are still more stringent. Vehicles may not automatically pass California's requirements if they were manufactured outside of the state. For example, passenger cars in California can release no more than 0.2 g/mi of NOx, and zero PM emissions. Federal standards, however, allow certain light-duty vehicles (which includes passenger cars) to release up to 0.6 g/mi of NOx and up to 0.08 g/mi of PM.

I Want to Buy a Car in California: What Should I Do First?

New car buyers who live in California, or plan to move there, should check out This website, operated by the California Air Resources Board, can help potential buyers search for the most efficient, law-abiding cars their budget allows. Users can search with a variety of criteria, such as Make/Model, Smog Rating, and Greenhouse Gas Rating.

One easy way to tell if a vehicle is California certified--that is, manufactured to conform to the state's standards--is to check under the hood. There should be an emissions label that states whether the vehicle meets California regulations, or is legal to sell in California.

I Have a Car: What Now?

For many car owners in California, it is not enough that the vehicle was made to meet the state's requirements. Vehicles also must adhere to the California Smog Check Program. Under this program, car owners must pass a smog check before registering their vehicle with the state. This law applies whether they purchased their car as a California resident, or whether they recently moved to California with a vehicle from another state. Under California law, a "new" car is any vehicle with less than 7,500 miles when it was purchased or traded, whether or not it is registered in another state.

Smog checks can be performed at several types of locations:

  • STAR stations, which meet Bureau of Automotive Repair (BAR) performance standards, and may either perform tests only, or both tests and repairs
  • Test-Only stations, which perform emissions tests but do not make repairs
  • Test-and-Repair stations, which can perform both tests and repairs
  • Some locations are Repair-Only, and cannot perform smog checks.

When taking a vehicle in for an inspection, drivers should bring along the following documents:

  • A valid driver's license
  • Proof of insurance
  • Title (if the primary driver owns the vehicle)
  • Registration (either in California or out-of-state)

The fees involved in the smog check can vary by location, so vehicle owners should call ahead to get an estimate.

In some counties, vehicles may have to undergo a smog check every two years. The California Department of Motor Vehicles offers a list of those areas. Some exemptions to this rule include motorcycles; trailers; diesel vehicles made before 1997; electric cars; natural gas-powered vehicles weighing more than 14,000 lbs; and gasoline-powered vehicles made before 1976. For cars six model years old or less, owners can pay an annual smog abatement fee for the first six registration years, rather than have their vehicle tested every other year.

Smog inspections involve a visual test, when an inspector checks for blue or black smoke coming from the tailpipe. The inspections also include a machine test, when the inspector uses a machine to check certain vehicle components. Each component must pass this test for the entire vehicle to pass the smog inspection. If the car passes the smog check, the owner is issued a smog certificate.

Anyone who sells a vehicle more than four years old in California also must have a smog check performed, and provide the smog certificate before or at the time of the sale. Exemptions to this rule include vehicles that were registered in California and acquired from a spouse, sibling, child, or parent.

When registering a vehicle in California for the first time, the owner must visit a local state DMV office, with the following documents:

  • Proof of ownership
  • Smog certificate.
  • Valid ID
  • Proof of car insurance.
  • A completed Application for Title or Registration (Form REG 343)
  • Payments for the $46 registration fee, $23 CHP fee, title fees, and taxes

What if My Car Doesn't Meet the Emissions Requirements?

It may not be worth it fix your car if it doesn’t meet the emissions requirements. It may be better to sell it and buy a new car. Click the button below to see how much your car is worth.

If a vehicle fails the Smog Check, the owner can first contact BAR's Referee Program at 800.622.7733, where they can find dispute resolution and inspection assistance. Based on their income, owners also may be eligible for repair assistance or vehicle retirement through the bureau's Consumer Assistance Program, which can be reached at 800.952.5210.

A vehicle that was not manufactured to meet California emissions standards may still be registered in California. The vehicle must be first registered to its owner in his or her home state--or the last state of military service if the owner is a member of the military. The owner must provide evidence of this previous registration when applying for vehicle registration in California. A vehicle also may be registered in California without being built to state standards if it was obtained as part of a divorce or inheritance; purchased to replace a California-registered vehicle that was stolen or destroyed while being used out-of-state; an emergency vehicle; or a street motorcycle from 2005 or earlier.

If a vehicle was imported from outside of the United States, it may not be able to be modified or repaired to meet either federal or state requirements. Owners of such vehicles should contact the California Air Resources Board (ARB) for further information. Direct-import vehicles less than two years old cannot be converted to California emission standards, and older vehicles may be impossible or costly to modify.

Please note that laws and regulation are subject to change, so you should always check your local Department of Motor Vehicles office to make sure you have all the documents required.