# California — Vehicle emissions testing: which counties require it, in which states

For California, counties where testing is required is Alameda Butte Colusa Contra Costa Fresno Glenn Kern Kings Los Angeles Madera Marin Merced Monterey Napa Nevada Orange Sacramento San Benito San Francisco San Joaquin San Luis Obispo San Mateo Santa Barbara Santa Clara Santa Cruz Shasta Solano Stanislaus Sutter Tehama Tulare Ventura Yolo Yuba, verified against its source on 2026-08-19.

- **State:** California _(our reading, not quoted from the source)_
- **Counties where testing is required:** Alameda Butte Colusa Contra Costa Fresno Glenn Kern Kings Los Angeles Madera Marin Merced Monterey Napa Nevada Orange Sacramento San Benito San Francisco San Joaquin San Luis Obispo San Mateo Santa Barbara Santa Clara Santa Cruz Shasta Solano Stanislaus Sutter Tehama Tulare Ventura Yolo Yuba _(verified: appears in the quote below)_
- **Vehicles covered / exempt:** Gasoline, hybrid, and alternative-fuel vehicles - model year 1976 and newer _(per bar.ca.gov, not stated by the source above)_
- **Program / authority:** Smog Check Program _(per bar.ca.gov, not stated by the source above)_
- **How often:** every other year to renew your vehicle registration _(per bar.ca.gov, not stated by the source above)_

## What the source says

> If you live in one of these counties, you need a smog inspection when you renew your vehicle registration. Alameda Butte Colusa Contra Costa Fresno Glenn Kern Kings Los Angeles Madera Marin Merced Monterey Napa Nevada Orange Sacramento San Benito San Francisco San Joaquin San Luis Obispo San Mateo Santa Barbara Santa Clara Santa Cruz Shasta Solano Stanislaus Sutter Tehama Tulare Ventura Yolo Yuba

## What bar.ca.gov says

> Vehicles that need a Smog Check Gasoline, hybrid, and alternative-fuel vehicles - model year 1976 and newer Diesel vehicles - model year 1998 and newer

Source: https://www.bar.ca.gov/consumer/smog-check-program

## What bar.ca.gov says

> A Smog Check is required every other year to renew your vehicle registration.

Source: https://www.bar.ca.gov/consumer/smog-check-program

## Source

- https://www.dmv.ca.gov/portal/vehicle-registration/smog-inspections/
- https://www.bar.ca.gov/consumer/smog-check-program
- https://www.bar.ca.gov/consumer/smog-check-program

Last verified: 2026-08-19. Review by: 2027-08-19.
Part of [Vehicle emissions testing: which counties require it, in which states](https://referencesource.org/vehicle-emissions-testing-by-state/).