Can you refuse a breathalyzer in California? It is one of the most common questions I get, and the honest answer is that it depends entirely on which breath test you mean, because there are two very different ones, and the rules for each are opposite. I am Joel Brand, and I defend DUI cases across California. Here is the distinction clearly, what refusing actually costs, and why this is not a decision to make on a hunch at the roadside.
There are two breath tests, and people confuse them
The single biggest source of confusion in California DUI law is that the word breathalyzer covers two different devices used at two different moments. The first is the small handheld device an officer offers at the roadside, before any arrest. The second is the larger evidentiary machine at the police station, or a blood draw, after you are arrested. They look similar and they both measure alcohol, but legally they could not be more different.
The roadside handheld test is usually optional
The handheld roadside device is called a preliminary alcohol screening test, or PAS. For most adult drivers, those 21 and over who are not already on DUI probation, the PAS is voluntary. It is an investigative tool the officer uses to develop probable cause to arrest, and the officer is supposed to advise you that it is optional. Many people blow into it believing they have no choice, when in fact, for them, it is no different from the field sobriety tests in that it is generally something you can decline. I cover the roadside tests in refusing field sobriety tests.
The exceptions: under 21 and DUI probation
There are two important groups for whom the roadside PAS is not optional. If you are under 21, California's zero-tolerance scheme requires you to submit to a PAS, and refusing it triggers a license suspension on its own. The same is true if you are already on probation for a prior DUI. For those drivers, the roadside device carries the same kind of consequences as the evidentiary test, so the usual advice about it being optional does not apply.
The post-arrest evidentiary test is not optional
Once you are lawfully arrested for a DUI, a different rule takes over. Under California's implied consent law, found in Vehicle Code 23612, by driving in the state you are deemed to have agreed to submit to a chemical test of your breath or blood after a lawful DUI arrest. This is the evidentiary test, and refusing it is what carries the serious, automatic penalties people associate with refusing a breathalyzer. California no longer uses urine testing for alcohol, so the choice is generally breath or blood.
What refusing the evidentiary test actually costs
Refusing the post-arrest chemical test is expensive in ways that often outweigh whatever you think you are avoiding. A refusal triggers a longer license suspension than a standard DUI suspension, a full year for a first refusal, and unlike a standard first-offense suspension, a refusal generally does not allow the early restricted license that lets many people keep driving. A refusal also adds a sentencing enhancement on top of the DUI itself if you are convicted, which I explain in the refusal sentencing enhancement, and the separate license consequences are covered in the refusal license suspension. On top of all that, the prosecutor can argue your refusal to a jury as evidence that you knew you were guilty.
Refusing does not stop the test anyway
Here is the practical reality that surprises people. Refusing often does not even keep your blood alcohol out of evidence. Officers can and routinely do obtain a warrant, sometimes electronically in a matter of minutes, and then draw your blood whether you consent or not. So in many refusal cases the state ends up with a blood result and a refusal enhancement, which is the worst of both worlds. That is why refusing the evidentiary test is rarely the clever move it can feel like in the moment.
Breath or blood, if you do test
If you submit to the evidentiary test, you generally get to choose between breath and blood. Each has tradeoffs. A breath test is quick and gives an immediate number, but breath machines depend on calibration and proper procedure and cannot be retested later. A blood sample is preserved, which means your defense can have it independently re-analyzed, and blood draws have their own chain-of-custody and handling requirements that can be challenged. There is no universally right answer, but understanding the difference helps.
Refusal cases can still be defended
A refusal allegation is not the end of the case. The penalties for refusing only apply if the arrest was lawful and if the officer properly advised you of the consequences of refusing, in the specific way the law requires. Officers get that advisement wrong, or skip it, more often than you would expect, and confusion that looks like refusal is not always a legal refusal. The common errors are described in common police mistakes during a refusal and post-arrest test refusal.
The bottom line
So, can you refuse a breathalyzer in California? The roadside handheld PAS is usually optional for adults who are not on DUI probation. The post-arrest evidentiary test is not optional, and refusing it triggers a longer suspension, a sentencing enhancement, and often a warrant-drawn blood test anyway. Whatever happened in your case, including a refusal, the situation is more defensible than it feels, and the 10-day deadline that protects your license is the same either way, a point I explain in your DUI creates two separate cases. Get a free written case analysis below, or call me directly at (888) 271-6644. I answer my own phone, 24/7. You can also read more from the DUI blog.