What Happens If You Refuse a Breathalyzer in California?


It sounds logical in the moment: if they don’t have my BAC reading, they can’t prove I was drunk, right?

Wrong. And refusing a chemical test in California will likely make your situation significantly worse.

Here’s what actually happens.


When you got your California driver’s license, you legally agreed to something called implied consent. That means by driving on California roads, you’ve already consented to chemical testing (breath or blood) if you’re lawfully arrested for DUI.

The key word is arrested. The rules are different for pre-arrest roadside tests vs. post-arrest chemical tests:

  • Pre-arrest roadside breathalyzer (PAS test): You can legally refuse this one if you’re over 21 and not on DUI probation. It’s optional before arrest.
  • Post-arrest chemical test (breath or blood at the station): You cannot legally refuse this without consequences. Once you’re arrested, you must comply.

Most people who “refuse” are refusing the post-arrest test. That’s where the penalties hit hard.


The Consequences of Refusal

On Your Driver’s License (DMV)

A refusal triggers an automatic 1-year license suspension — regardless of whether you’re ever convicted of DUI in court.

For comparison: a standard first-offense DUI with BAC of 0.08%+ gets you 4 months of suspension.

Refuse once: 1 year. Refuse again within 10 years: 2 years. Third refusal: 3 years.

You can fight this at a DMV hearing, but the bar for winning a refusal case is high.

In Criminal Court

The refusal can be used as evidence against you. Prosecutors often argue it like this:

“If you weren’t drunk, why did you refuse the test?”

A jury can hear that argument. Judges can consider it. It often comes across as consciousness of guilt.

Enhanced Penalties

If you’re convicted of DUI with a refusal allegation, California law adds extra penalties on top of the standard DUI punishment:

OffenseMandatory Jail Addition
First DUI + refusalMinimum 48 additional hours in jail
Second DUI + refusalMinimum 96 additional hours
Third DUI + refusalMinimum 10 additional days

These are minimums added on top of whatever the base DUI penalty is.


Does Refusing Actually Help You Beat the Case?

Almost never.

Officers who suspect DUI have other evidence: your driving behavior, field sobriety test performance, physical observations (slurred speech, smell of alcohol, red eyes), and your statements. A DUI charge can be prosecuted without a BAC number.

In fact, many DUI attorneys say a refusal makes the case harder to defend because:

  1. It gives prosecutors a narrative (guilty consciousness)
  2. It adds an automatic license suspension separate from the DUI charge
  3. The enhanced penalties are mandatory, not discretionary

The One Situation Where It Gets Complicated

If you have a blood draw done instead of a breath test, you can request that a portion of your blood sample be independently tested by a lab of your choosing. This is a legitimate defense strategy — not a refusal.

Refusal means you said no to the entire process. Submitting to a blood draw and later challenging the results is completely different and generally much more defensible.


What To Do Instead

If you’re in a situation where you’re being asked to take a chemical test after a DUI arrest:

  • Take the test. The consequences of refusing are almost always worse than the BAC result.
  • Stay quiet otherwise. You don’t have to answer questions or explain yourself.
  • Contact a lawyer immediately. A DUI attorney can challenge the test results, the stop, the arrest — all of it. But they need something to work with.

A high BAC is a problem. Refusing creates two problems — the DUI charge and the refusal — with fewer ways to fight back.


Real Quick Summary

Standard DUI (0.08%+)DUI + Refusal
License suspension (first offense)4 months1 year
Used against you in court?NoYes
Extra jail time required?NoYes
Easier to fight?YesHarder

The math almost never adds up. Take the test.


See also: What Happens at a DMV Hearing — whether you took the test or refused, you have 10 days to request one.