# How long does a smog check take?

The test itself takes about 20 to 30 minutes for a gasoline car from model year 2000 or newer, because the station reads the on-board diagnostics (OBD) computer instead of measuring the tailpipe. Older cars get a tailpipe test and can take longer. Waiting time depends on the station: call ahead, or go early on a weekday.

## Key facts

- Gasoline cars from 2000 and newer get an OBD-based test in California.
- Cars from 1999 and older get a tailpipe emissions test, which takes longer.
- The result is sent to the DMV electronically as soon as the test is done.

## What happens during those minutes

- **Visual check** of the emissions parts that should be there.
- **Functional check** of the check engine light and, on older cars, the gas cap.
- **OBD scan** of stored trouble codes and readiness monitors (2000 and newer), or a **tailpipe test** (1999 and older).

## How to spend less time there

- Drive at least 15 to 20 minutes before the test so the engine is warm.
- Call the station and ask about the wait; many take walk-ins, some take appointments.
- Bring your DMV renewal notice ([what to bring](https://appointauto.com/guides/what-to-bring-to-smog-check/)).

## Next step

[Find a smog check station in your city](https://appointauto.com/ca/) · [What to bring to a smog check](https://appointauto.com/guides/what-to-bring-to-smog-check/)

Official sources: [bar.ca.gov](https://www.bar.ca.gov/).

## Related questions

- [Where can I get a smog check near me?](https://appointauto.com/answers/where-to-get-a-smog-check-near-me/)
- [Do I need an appointment for a smog check, and are stations open on weekends?](https://appointauto.com/answers/smog-check-walk-in-or-appointment/)
- [How long is a California smog certificate valid?](https://appointauto.com/answers/how-long-is-a-smog-certificate-valid/)
- [Can I get a smog check if my registration is expired?](https://appointauto.com/answers/smog-check-with-expired-registration/)

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Source: https://appointauto.com/answers/how-long-does-a-smog-check-take/ · Last updated 2026-10-26. Station details are compiled from public listings and can change; call the shop to confirm hours and prices before you go.