In California, the legal blood alcohol level is 0.08% for most drivers age 21 and older operating a non-commercial vehicle. Commercial drivers face a 0.04% limit, drivers under 21 and anyone on DUI probation face a 0.01% limit, and you can still be arrested and convicted below any of those numbers if alcohol or drugs visibly impaired your driving.
The 0.08% Rule for Most Drivers
If you are 21 or older behind the wheel of a passenger vehicle, driving with a BAC of 0.08% or higher violates California Vehicle Code 23152(b). This is a “per se” offense: the chemical test reading alone is enough for a conviction, with no separate showing that your driving looked impaired.1California Legislative Information. California Code VEH 23152 – Driving Under the Influence A test taken within three hours of driving that shows 0.08% or more carries a legal presumption that you were at that level when you were actually driving.
Lower Limits That Apply to Specific Drivers
Commercial Drivers: 0.04%
Operating a commercial vehicle with a commercial license drops your limit by half. Vehicle Code 23152(d) sets the threshold at 0.04%.1California Legislative Information. California Code VEH 23152 – Driving Under the Influence A conviction typically carries a one-year disqualification of the commercial license on a first offense, and a lifetime disqualification on a second.
Drivers Under 21: 0.01%
California enforces a zero-tolerance rule for underage drivers. Under Vehicle Code 23136, a BAC of just 0.01% is enough to trigger a violation, a level that a single drink, some medications, or even certain mouthwashes can produce.2California Legislative Information. California Code VEH 23136 – Offenses by Persons Under 21 Involving Alcohol A first violation brings a minimum one-year DMV license suspension.3California Legislative Information. California Code VEH 13353.3 – Suspension Periods If an underage driver’s BAC reaches 0.08%, prosecutors can add the standard adult DUI charges on top.
Drivers on DUI Probation: 0.01%
If you are currently on probation for a prior DUI under Vehicle Code 23152 or 23153, the same 0.01% limit applies to you. Any detectable alcohol is treated as a probation violation under Vehicle Code 23154, and it exposes you to new criminal penalties on top of the consequences for breaching probation.4California Legislative Information. California Code VEH 23154 – Driving on DUI Probation
Being Charged Below the Limit
A BAC under 0.08% does not shield you from a DUI. Vehicle Code 23152(a) separately makes it illegal to drive “under the influence” of alcohol, with no fixed number attached. The question is whether alcohol impaired your ability to drive as a sober person would under the same conditions.1California Legislative Information. California Code VEH 23152 – Driving Under the Influence Officer observations, field sobriety test performance, and a breath result as low as 0.05% can together support a conviction.5California Department of Motor Vehicles. California Driver Handbook – Alcohol and Drugs
The same framework reaches drugs. Vehicle Code 23152(f) prohibits driving under the influence of any drug, including prescription and over-the-counter medications, and subdivision (g) covers the combination of alcohol with any drug. There is no per se BAC-style number for drugs; cases rest on officer observations, blood test results confirming the substance, and sometimes a drug recognition expert.1California Legislative Information. California Code VEH 23152 – Driving Under the Influence
What a Reading of 0.15% or Higher Means
A BAC of 0.15% or higher is treated as a “special factor” at sentencing under Vehicle Code 23578. Judges can impose tougher probation conditions, longer alcohol education programs, and steeper fines when the reading is nearly double the legal limit.6California Legislative Information. California Code VEH 23578 – High BAC Enhancement Refusing the chemical test triggers the same enhancement, so declining the test to avoid a high number does not avoid this part of the law.
Refusing the Chemical Test
Driving on California roads is itself legal consent to a breath or blood test if an officer lawfully arrests you for DUI. Vehicle Code 23612 is the implied consent statute, and it applies from the moment you take the wheel.7California Legislative Information. California Code VEH 23612 – Implied Consent
Refusing makes things worse, not better. The DMV will suspend your license administratively for one year on a first refusal, two years with one prior DUI-related offense or refusal in the last ten years, and three years with two or more such priors. Refusal suspensions run longer than failed-test suspensions and do not come with a restricted license option during part of the term. The refusal itself can also be used against you as evidence at trial.7California Legislative Information. California Code VEH 23612 – Implied Consent
The Ten-Day DMV Deadline
A DUI arrest sets two separate cases in motion. One moves through the criminal court. The other is a DMV administrative action against your license, and it runs on its own clock. You have ten days from the date of arrest to request a DMV hearing to contest the suspension.8California Department of Motor Vehicles. Driving Under the Influence Miss it and the suspension takes effect automatically 30 days after the arrest, even if the criminal charges are later reduced or dismissed.
Criminal Penalties by Offense
California counts prior DUI offenses within a ten-year lookback window. Anything older than ten years does not count as a prior for sentencing. Each prior in that window pushes the minimum punishment higher. The base fine at every level runs $390 to $1,000, but penalty assessments and court fees typically push the real amount owed well above that range.
- First offense: 96 hours to six months in county jail, with at least 48 continuous hours; base fine of $390 to $1,000; license suspension.9California Legislative Information. California Code VEH 23536 – First DUI Penalties
- Second offense within ten years: 90 days to one year in county jail; base fine of $390 to $1,000; two-year license suspension.10California Legislative Information. California Code VEH 23540 – Second DUI Penalties
- Third offense within ten years: 120 days to one year in county jail; base fine of $390 to $1,000; three-year license revocation; habitual traffic offender designation.11California Legislative Information. California Code VEH 23546 – Third DUI Penalties
- Fourth or later offense within ten years: can be filed as a felony, with 180 days to one year in county jail or a state prison sentence, plus the same base fine. A felony filing is also available if you have any prior felony DUI, regardless of how many total priors you have.
A DUI that causes bodily injury to another person is a separate, more serious offense under Vehicle Code 23153. Prosecutors can file it as a misdemeanor or a felony depending on the severity of the injuries and your record, and a felony conviction carries potential state prison time.
Ignition Interlock Device Requirements
California’s statewide ignition interlock device program runs through December 31, 2032. The device prevents the engine from starting if it detects alcohol on the driver’s breath.12California Department of Motor Vehicles. Statewide Ignition Interlock Device Pilot Program Installation periods scale with your prior record:
- First DUI with no priors: up to six months, at the court’s discretion, and can serve as an alternative to a full license suspension.
- Second DUI: mandatory 12 months.
- Third DUI: mandatory 24 months.
- Fourth DUI or felony DUI: mandatory 36 months.
If the DUI involved injury, the mandatory periods are longer, starting at 12 months for a first injury offense and reaching 48 months for repeat offenders with a prior felony DUI.13California Legislative Information. California Code VEH 23575.3 – Ignition Interlock Device Requirements Installation fees, monthly calibration charges, and removal fees come out of the driver’s pocket.