Does a backgrond check show county jail time served?

I'm looking for work and I am wondering if I need to tell the employer that I spent 100 days in the county jail last year for getting my 3rd DWI? I have quit drinking since being released and turned my life around for the better. If the application asks if I have any misdemeanors, I answer truthfully. At that point the employer usually asks if I have been to prison. I've been saying no and that I was put on probation. I'm currently on probation for the DWI's and have never been to state prison. Should I tell the employer that I went to county jail, or just say that I attended a community service program on the weekends for several months? The employer is going to know that I was punished in some fashion. I hate twisting the truth, but I tried that when first starting my job search and had no success when revealing my stay in the county jail.