DUI Chemical Tests in California

As DUI defense attorneys, we have many goals when it comes to defending people against driving under the influence charges. One of our goals is to help people better understand California’s DUI laws, especially since they can be difficult for the average person to understand.

In this post, we explain the state’s laws as they pertain to DUI and chemical testing. When we refer to chemical testing, we’re talking about breath, blood and urine tests, which measure the amount of alcohol in a person’s system. For the most part, law enforcement uses blood and breath tests for DUI cases, but occasionally they will use a urine test, especially when they are testing for the presence of alcohol and drugs in the DUI suspect’s system.


Under Section 23612 of the California Vehicle Code, when a person drives a motor vehicle in the state, he or she is deemed to have given their “consent” to a chemical test of their blood, breath, or urine for the purpose of determining the alcohol or drug content in their blood. Chemical testing is incidental to a lawful DUI arrest and it’s administered at the direction of a peace officer who has “reasonable cause” to believe the suspect was driving under the influence of alcohol or drugs under Sections 23140, 23152, or 23153.


If you’re pulled over and the law enforcement officer suspects that you’ve been driving under the influence of alcohol, illegal drugs, or even lawfully prescribed medication, and you refuse to submit to a chemical test after being arrested for DUI, you will face a mandatory license suspension even if you were NOT drinking prior to driving.

If you fail to complete a chemical test after a DUI arrest, or if you fail to take a chemical test at the request of a police officer, you will face an automatic one year driver’s license suspension, and mandatory imprisonment if you are ultimately found guilty of DUI under Sec. 23152 or 23153.


Under California law, if you are lawfully arrested for driving under the influence of alcohol, drugs, or a combination of alcohol and drugs, you will be given the choice between a blood or breath test, and the officer will ask, “Which one do you want to take?”

Which test should you take? If you were not drinking at all, or if you had very little to drink, we recommend taking a blood test because it is more accurate than a breath test. If your blood alcohol concentration (BAC) is questionable (you’re worried it may be too high), or if you probably had too much to drink, we recommend choosing the breathalyzer test because it is more prone to error, thus it’s easier to challenge in court.

If you’re looking for an experienced DUI attorney, call our office to work with a Board-Certified DUI specialist who is a member of the National College for DUI Defense!

Related Posts
  • How Will a DUI Impact Your Insurance Rates? Read More
  • Ultimate Guide to DUI Court Procedures Read More
  • 4 Types of DUI Charges Read More