What is a Test-Only Smog Center?

Mary McMahon
Mary McMahon

A test only smog center is a smog testing location which only performs smog tests, and does not execute repairs. It tends to be much more rapid, because it specializes in smog testing. If your vehicle is likely to pass the smog test it is an excellent choice because these centers are also usually less expensive. In states such as California with high air pollution and a large number of vehicles on the road, there are numerous test only smog locations.

California's Department of Motor Vehicles randomly selects vehicles for smog testing and notifies the owners by mail.
California's Department of Motor Vehicles randomly selects vehicles for smog testing and notifies the owners by mail.

A test only smog center is differentiated from a test and repair smog center because the test only center is not authorized to perform vehicle repairs. As a result, if your vehicle fails the smog test at such a center, you will have to find a test and repair facility. Often the test and repair center will charge for another smog test as part of the diagnostic process. For this reason, if you are in doubt about the ability of your vehicle to pass a smog test, you should choose a test and repair station, not a test only smog station.

Some states have areas known as Enhanced Smog Check Areas, where drivers will be expected to smog check their vehicles more regularly, especially if they drive vehicles classified as gross polluters. Gross polluters are vehicles which have been known to exceed state smog limits by more than 200%, and some models of vehicle are more likely to be gross polluters. Gross polluters are also known as High Emission Profile vehicles. The state randomly selects High Emission Profile vehicles for smog testing, directing them to a test only smog center.

Vehicles registered in Enhanced Smog Check Areas will also be subject to random smog checks even if they don't have a High Emission Profile. The Department of Motor Vehicles randomly selects vehicles for smog testing and notifies the owners by mail. Partly this is designed to keep drivers in regulatory compliance, and also to test the effectiveness of the smog check system.

Many states offer abatement programs, where drivers who demonstrate that a vehicle needs costly repairs may be exempt from smog requirements or able to receive assistance from the state. If your vehicle happens to fail a smog test and costly repairs are estimated, ask the staff at the smog testing center about your options.

Regular smogging of your vehicle not only ensures that it is in regulatory compliance. It will also identify potential safety hazards, assuring that you will drive a clean, safe, and healthy vehicle. World wide, emissions from a wide variety of sources are an issue of major concern, and drivers should do their part to help reduce personal emissions.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


In our area test, only smogs are not generally cheaper, because we do not do repairs. The shops that do repairs are generally cheaper because they make money when you fail because generally you get the repair work done at the same place. So your 29.99 failure turns into a $300 repair. Test only stations were created to give consumers the option to go to a place that would not fail car that did not truly require repair work just to make money. Because a test only cannot perform repairs, we have no bias to fail you and are prohibited by law from referring to a repair shop (so we won't back door you, either).

By the way, a vehicle is not a gross polluter until it fails, and all high emitter profile cars are directed to test only centers, which are cars more likely to fail than others (and the repair guys know this) so why go to the tiger pit wrapped in a steak when you can go with a spear and have a chance?

Most stations charge for a re-test, most that offer pass or don't pay only extend the offer if the vehicle is repaired at the shop. also people in the enhanced areas are not required to get a test more often, unless you compare it to a "change of ownership area" which is when you only have to get a smog if selling the car.

Both the basic and enhanced areas get smogged every other year once the vehicle reaches is 6th renewal period, and for change of ownership transactions after four. It's frustrating when folks get upset at test only stations as being a crock, when it's the repair shops who were ripping people off, causing us to come into existence in the first place.


No, if your car is in decent mechanical condition, then it is *smart* to go to a test-only station. It's when you have doubt that your car will not pass to bring it into a Smog Check Station so they can thoroughly diagnose your vehicle. But it's up to you...


test only sounds kind of like a crock. i just received a registration renewal (in California) for testing at a test only center.

from the definition above, if i don't pass, I'll then have to go to a smog and repair station and shell out extra cash for retesting rather than going to, say, a test-don't pass-don't pay-repair center.

am i understanding this correctly?

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