If you’re under 21 and you got stopped for suspected DUI, the situation can feel unfair and confusing—especially if you weren’t “drunk,” you only had a small amount to drink, or you didn’t feel impaired at all. But California has a strict “zero tolerance” system for drivers under 21. That means you can face serious consequences—especially to your license—even when an adult driver might not be charged in the same situation.
This page focuses on Vehicle Code 23136 (VC 23136), California’s “zero tolerance” law for underage drinking and driving. It often involves a very low BAC threshold (0.01%) and typically triggers DMV action that can impact school, work, and your ability to drive.
What Is “Zero Tolerance” Under VC 23136?
California’s “zero tolerance” rule is straightforward in concept: if you are under 21, it is unlawful to drive with a BAC of 0.01% or higher, as measured by a preliminary alcohol screening (PAS) test or other chemical test. That “0.01%” threshold is extremely low, and in real life it can be triggered by a small amount of alcohol or alcohol that’s still present in the mouth from very recent use.
It’s also important to understand that VC 23136 is not the same thing as a “standard adult DUI.” It’s a different legal and DMV framework that often moves on an administrative track, separate from what happens in criminal court.
This page and website provide general information in plain English, not legal advice. Laws and local court/DMV practices vary and can change, so don’t rely on this content for your case—talk to a qualified attorney promptly to review your specific facts, especially if you face charges, a DMV action, or a deadline. In many cases, you’re fighting two battles at once: the DMV process and the criminal court case.
Under 21 BAC Limits in California (0.01 vs. 0.05 vs. 0.08)
Under-21 drivers can face different consequences depending on the BAC level and how the case is charged. At 0.01%, VC 23136 is the “zero tolerance” rule and can trigger underage enforcement based on PAS or other chemical test results. At 0.05%, California has a separate underage statute (VC 23140) that makes it unlawful for a person under 21 to drive with 0.05% or more BAC. And at 0.08%, an under-21 driver can face the same “standard DUI” BAC theory used for adults under VC 23152(b).
Key point: underage cases are often charged in overlapping ways depending on the facts, and DMV consequences can run separately from the court case—so strategy often has to account for both tracks.
DMV Consequences: License Suspension and How Long It Lasts
For many under-21 drivers, the biggest immediate impact isn’t the court case—it’s the DMV action. The DMV process is separate from criminal court, uses different standards, and can move quickly, which means your license can be suspended or revoked even while your court case is still pending. The DMV also treats APS/Zero Tolerance actions as independent from other DMV actions and any criminal penalties, so a “good” outcome in court doesn’t automatically undo what the DMV is doing.
A one-year suspension is common in under-21 testing and refusal situations. In DMV guidance, if you were under 21 and you refuse or fail to complete a PAS test or other chemical test, a first offense typically triggers a one-year suspension, with longer revocation periods for subsequent events within 10 years. That’s why underage DUI defense is often a two-track fight: protect the license at the DMV early, and defend the court case if one is filed.
Refusing Tests Under 21: What Happens?
Refusal is a major risk for under-21 drivers because the DMV may treat “refuse” and “fail to complete” as license-triggering events, even when the situation felt confusing in the moment. DMV guidance explains that underage drivers who refuse or fail to complete the PAS or other chemical test can face a one-year suspension for a first offense, a two-year revocation for a second offense within 10 years, and a three-year revocation for a third or subsequent offense within 10 years.
That’s why refusal issues often deserve their own focus: DUI Refusal. Even if someone believes the refusal was “reasonable” at the time, the DMV may still treat it as a refusal unless the defense can show the legal requirements weren’t met or the facts don’t support the refusal claim.
Common Evidence in Underage DUI Cases
Underage DUI cases often involve a mix of roadside investigation evidence and DMV paperwork, and the file can look different depending on whether it started as a traffic stop or a checkpoint. Common evidence includes the officer’s stated reason for the stop—such as weaving, speeding, an equipment issue, or checkpoint contact—along with bodycam and dashcam video that can confirm or contradict the officer’s narrative. The case may also include statements or admissions attributed to the driver, like “I had one drink,” and PAS breath test results taken at the roadside. In some situations, there may also be post-detention or post-arrest test results, including breath or blood testing.
Other common components include field sobriety tests (FSTs), DMV notice forms and paperwork that trigger license consequences, and timeline evidence showing when the driving occurred, when the stop happened, and when testing took place. That timeline can be critical in underage cases because the legal consequences can hinge on what was requested, what test was used, and what the results are being used to prove.
A strong defense usually depends on details—the exact timeline, what the video actually shows, what the paperwork says, and whether the officer followed proper procedures at each step.
The PAS Test: What Under-21 Drivers Need to Know
Many underage DUI cases start with a PAS test, which is often a handheld breath test given at the roadside during the investigation. In California’s under-21 framework, it’s important to understand that there’s a difference between roadside screening used to develop “reasonable suspicion” or “probable cause,” and post-detention or post-arrest chemical testing that can trigger separate DMV actions.
For practical purposes, the big takeaway is this: under-21 drivers can face immediate license consequences—and in some situations, refusal consequences—based on how testing was requested, explained, and documented. That’s why the timeline matters, the paperwork matters, and the video often matters.
If the PAS result is central to the case, the defense may focus on whether the device was reliable and used properly, whether the test was administered correctly, and whether factors like mouth alcohol or timing could have affected the reading. The defense will also compare the officer’s narrative to the video and the time stamps, because inconsistencies can undermine the accuracy and significance of what the PAS reading is being used to prove.
VC 23136 vs. VC 23140 vs. VC 23152: Which One Applies?
This is where a lot of families get lost, because under-21 cases can involve overlapping laws depending on the BAC level and what the officer claims happened. In plain English, the starting point is usually the test result and the theory the state is using.
VC 23136 (0.01%+): “Any Measurable Alcohol”
If you’re under 21 and a test shows 0.01% BAC or higher, VC 23136 can apply. This is the “zero tolerance” rule and it’s often treated as a DMV-driven issue that can affect your license quickly, even if the case never looks like a “regular DUI” case.
VC 23140 (0.05%+): Underage Alcohol Offense (Infraction-Level)
If the BAC is 0.05% or higher, VC 23140 may apply in addition to—or alongside—VC 23136 depending on the facts. This is often described as an underage alcohol-driving offense that can create court consequences even when the BAC is below the adult DUI threshold.
VC 23152 (0.08%+ or Impairment): Standard DUI
If the BAC is 0.08% or higher, or the state claims you were impaired, prosecutors may pursue the standard DUI statute under VC 23152 even if you’re under 21. This is where the case starts to look more like an adult DUI prosecution, but with additional underage-related consequences layered on top.
A defense lawyer’s job is to cut through the confusion by looking at what you’re actually accused of, what the test results really show, whether the stop and investigation were lawful, and what the DMV is trying to do to your license on its separate track.
Defenses That Can Help in Under-21 DUI Cases
Under-21 cases are different because the BAC thresholds are low and the DMV consequences can be severe. A strong defense usually focuses on the details that actually drive outcomes—whether the stop was lawful, whether the testing and documentation were handled correctly, and whether the DMV can really prove what it needs to prove under its separate process.
Challenge the Legality of the Stop
Every DUI case starts with the stop, and the officer must have a lawful reason to pull the car over. If the stop was based on an assumption, a weak claim of a Vehicle Code violation, or a justification that doesn’t match the video or facts, the defense may challenge evidence gathered afterward.
Challenge the Detention and Testing Process
Underage cases often hinge on how testing was requested, administered, and recorded. The defense may focus on whether the testing device was used correctly, whether proper procedures and observation periods were followed where applicable, whether the timeline supports the alleged BAC, and whether the officer’s report matches what the video and time stamps show. When the paperwork and the footage don’t line up, it can create real leverage.
Mouth Alcohol and Timing Issues (Especially With Low BAC)
In 0.01-level cases, tiny procedural issues can matter more because the number is so low. Recent drinking, burping, mouthwash, or other factors can distort a low reading, and the defense often examines whether the result reflects true BAC or a short-lived mouth-alcohol effect. In these cases, facts and timing are everything.
Refusal Defenses (If Refusal Is Alleged)
If refusal is alleged, the dispute is often about what was said and when, whether there was confusion between different types of tests, whether communication problems affected what was understood, or whether there was a legitimate medical or physical inability to complete the test. Under-21 refusal cases can be harsh at the DMV level, so the defense often focuses on whether the refusal allegation actually meets the legal requirements and is supported by reliable documentation.
Fight the DMV Action Strategically
DMV actions can be independent of court outcomes, which is why underage DUI defense is often a two-track strategy. A strong approach builds the DMV case early—because that’s often how you protect the ability to drive while the rest of the case unfolds, and because missing deadlines can lock in a suspension even before the court case is resolved.
What to Do After an Underage DUI Stop or Arrest
If this happened recently, the most helpful steps are the ones that protect your license early and preserve the facts before they get distorted. Start by acting quickly on DMV issues, because the DMV process can move fast and any suspension or revocation is handled separately from the court case.
You should also preserve every piece of paperwork and write down your timeline while it’s still fresh. Note when you drove, when you were stopped, when any tests happened, what you ate or drank, and exactly what was said, because under-21 cases often turn on timing, testing details, and what the officer documented. Avoid trying to “talk your way out of it” after the fact—statements can be used in both DMV and court contexts, and even well-intended explanations can be misunderstood or taken out of context.
Finally, talk to a DUI attorney who handles under-21 cases. Underage DUIs involve different statutes, different DMV frameworks, and different consequences than adult DUIs, and strategy often depends on understanding how those tracks overlap and how to fight both effectively.
Underage DUI FAQs
Can I really lose my license for 0.01 BAC?
Yes—California’s driver handbook and statute summaries reflect that under-21 drivers face consequences at 0.01% BAC.
Is VC 23136 the same as “regular DUI”?
No. VC 23136 is a zero-tolerance framework for under-21 drivers and often plays out through DMV action, while 0.08% and “impairment” cases are typically handled under standard DUI law.
What if I refused the PAS or chemical test?
DMV guidance states refusal/failure-to-complete under 21 can trigger a one-year suspension for a first offense, with longer revocations for later events.
What if my BAC is 0.05 or higher?
That can trigger underage DUI provisions (VC 23140) in addition to zero tolerance and DMV action, depending on the case facts.