“The legal limit in California for any adult, that’s somebody over 21, is 0.08 or above. The legal limit is 0.08. It is not uncommon for prosecutors to prosecute a DUI when the blood alcohol is even less than that.
For minors, the blood alcohol level is 0.05 but it’s also not uncommon for prosecutors if somebody, a minor, has a 0.04 to try to convict them as an impaired driver as opposed to having a certain blood alcohol level.
The other thing minors have to be concerned about is if you’re a minor in California and you’re driving with any alcohol in your system, 0.01 or more, the Department of Motor Vehicles will seek to suspend your driving privilege for one year, regardless of what happens in court.” – Daniel Greenberg