A first DUI conviction is punishable by a jail sentence of up to a maximum of 6 months. In addition to either jail time or probation, there is also a fine which, along with mandatory assessments can amount to over $1,500. In addition to jail and/or probation and fines, a suspension of your driver's license of up to 6 months may be imposed (usually four months for a first offense without aggravating factors), and attendance at a state-approved DUI school for three months or more will be required. If your blood alcohol level is 0.15% or higher, this could be increased to six or even nine months. It is possible but not typical in Marin County to also be required to perform community service, install an ignition interlock device (IID) in your car, and/ or Alcoholics Anonymous meetings. The usual period of probation (informal in most cases - meaning that you do not have to check in with a probation officer) is three years.
More severe penalties can be added due to various "enhancements". These can include having a child under the age of 14 in the car while driving under the influence, speeding in excess of 20 mph greater than the posted limit on surface streets or 30 mph on the highways, refusing to submit to chemical testing, or having one or more prior convictions within the previous ten years.