The mandatory minimum under the law is 120 days. You should retain an experienced DUI attorney to defend you immediately. Don't forget to request your DMV hearing w/in 10 days of your arrest or your license will automatically suspend on the 31st day after your arrest.
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It is highly recommended that you consult with and retain an experienced DUI lawyer in Los Angeles and that you request your APS hearing within 10 days of arrest. The first question should be what can I do to beat the case.
As for jail, it is common for people to serve less than the minimum jail time in actual county jail and instead serve "jail time" through a jail alternative program. An experienced private attorney or public defender can investigate the strengths and weaknesses of your particular case and your eligibility for alternative sentencing.
1 year maximum, 120 minimum... good time/work time results in minus 60 days. Sheriff's parole can result in further jail reduction. Electronic Monitoring (Home Detention) should be an option to help you keep your job. From your question you seem to just want to know the answer to your question and have resigned yourself to no hope. Even in a bad case an attorney can help though you have to decide how much that help is worth to you. Only a DUI atty will know the ends and outs of your case.