A first DUI offense is treated as a misdemeanor crime. The penalty includes a 12 month sentence, with a minimum of 24 hours in jail. Whatever non-jail time remains will be served on probation, and cannot be early terminated. While the judge can legally sentence you to serve up to 12 months in the county jail, you will normally spend the vast majority of the sentence on probation. During this time, you will be monitored by your probation officer, for which you will need to pay a supervision fee, usually around $50.00 per month while on active probation.