United States · Licensing examBecoming an apprentice in Illinois
You must be at least 16 and sponsored by a licensed plumber or an approved apprenticeship program. The apprenticeship runs 48 to 72 months. If you haven't applied for or passed the exam after the 6-year maximum, the apprentice license can't be renewed.
How do you apply for an Illinois plumbing license?
- At least 4 years as an Illinois licensed apprentice plumber
- At least 2 years of high school or the equivalent, plus an approved course of study
- The application, due at least 30 days before the exam date, with the fee
IDPH's application form lists $175 for Illinois licensed apprentices and $225 for plumbers registered or licensed in Chicago or outside Illinois. Fees aren't refunded. If you fail, there's a separate retake form.
IDPH doesn't publish the exam's format or pass mark on its plumbing page, so ask the department when you apply.
Plumbing contractors in Illinois
Contractors register with IDPH every year and must carry general liability, property damage and workers' compensation insurance. Adverts must show the plumbing license number, and letting someone else use your license number can be charged as a Class A misdemeanor with a $1,000 fine.
Renewal and checking a license
Plumber licenses are renewed by April 30, with continuing education every year. IDPH runs an online verification tool.
Sources: Illinois Department of Public Health · IDPH. Checked October 2026.
- Illinois Department of Public Health: Plumbing ↗
- IDPH: Application for Examination for Plumber's License ↗
Rules and fees can change, so check the official site before your test.