In Illinois, any business or individual performing plumbing work must have a license issued by the Illinois Department of Public Health or the City of Chicago. To become a licensed plumber, you must:

• complete at least two years of high school or the equivalent;
• complete four to six years of licensed apprenticeship;
• pass the Illinois Plumbing exam; and
• pay the appropriate licensing fee(s).

List of the counties from the state of Illinois