California DUI Laws Explained

By Javier Marín, Editor·Last reviewed September 2026·How we check this

A California DUI conviction triggers two parallel processes: a criminal case under California Vehicle Code §23152, and an administrative DMV action under the Administrative Per Se (APS) procedure. Both move quickly, both have separate timelines, and both have to be answered separately if you want the best possible outcome.

The legal threshold

California's per-se DUI thresholds:

Adults 21+: 0.08% BAC.
Drivers under 21: 0.01% BAC (zero tolerance).
Drivers on DUI probation: 0.01% BAC.
Commercial drivers (CDL): 0.04% BAC.
Rideshare or taxi drivers transporting passengers for hire: 0.04% BAC.

California also charges DUI on impairment evidence below the 0.08% threshold under VC §23152(a) — the "driving while impaired" subsection that doesn't require a specific BAC.

The 30-day APS suspension

After a DUI arrest where the BAC was 0.08% or higher (or the driver refused chemical testing), the arresting officer typically confiscates the driver's license on the spot and issues a 30-day "Order of Suspension and Temporary License." The temporary license expires after 30 days; thereafter the APS suspension begins:

4-month suspension for a first APS offense without aggravating factors.
1-year suspension for a chemical-test refusal first offense.
Longer for repeat offenders or aggravating circumstances.

The 10-day APS hearing window

You have 10 calendar days from the arrest to request an administrative hearing with the DMV's Driver Safety Branch. The hearing is separate from any criminal court proceeding and addresses three narrow questions: did the officer have lawful cause to stop and arrest, was the BAC at or above 0.08%, and did the driver lawfully take the chemical test. Winning the APS hearing does not affect the criminal case but does prevent the administrative suspension from going forward.

First-offense penalties (criminal)

A first-offense DUI conviction in California typically produces:

Up to 6 months in county jail (often suspended on first offenses without aggravating factors).
$390-$1,000 in base fines, plus penalty assessments that often triple the total.
A 6-month criminal license suspension (concurrent with the APS suspension).
Mandatory completion of a state-licensed DUI program (3, 6, 9, or 18 months depending on BAC and history).
Mandatory installation of an Ignition Interlock Device (IID) for at least 6 months on the offender's primary vehicle, since the 2019 statewide expansion.
SR-22 insurance filing for 3 years — see California car insurance.
3 years of informal probation.

Ignition Interlock Devices (IID)

California's IID requirement applies statewide for all DUI convictions involving a measurable BAC since January 2019. The device is installed at the driver's expense (typically $70-$150/month plus a $100-$150 install fee) and prevents the vehicle from starting if the driver's breath shows alcohol. IIDs collect rolling-test data that the installer reports to the DMV; failed tests can extend the IID period.

Aggravating factors

Penalties escalate quickly when any of these apply:

BAC at or above 0.15%.
An accident with injury or property damage.
A child under 14 in the vehicle (separate "child endangerment" charge under PC §273a).
Excessive speed at the time of arrest (20+ mph over the limit on surface streets, 30+ on freeways).
A prior DUI within the 10-year lookback window.
Refusing a chemical test.

Repeat offenses

A second DUI within 10 years brings mandatory minimum jail time, longer license suspension, longer IID requirement, and additional treatment programs. A third DUI within 10 years is a "habitual offender" classification with up to 16 months in state prison; a fourth in 10 years can be charged as a felony.