To be eligible for jury service, you must be a citizen of the United States; at least 18 years old; a resident of the county; not have a pending lawsuit. Jurors in all counties in Illinois must have the legal qualifications herein prescribed.Written verification of medical excuses, proof of non-citizenship, and non-residency will be required. A valid reason is required to be exempt from jury service. Upon reporting for service jurors can expect to serve for the duration of one trial. If you have any problems, call 309-672-6076. 2. After I have served, when am I qualified to serve again? The purpose of this booklet is to help you understand the things that happen and the terms that are used during a trial. If you have questions regarding your jury duty, call (618) 482-9148 and leave a message. Disqualified. To be unqualified or ineligible to serve jury duty under Illinois Law.