If you’re a licensed plumber in Illinois—or considering hiring an apprentice—you’ve probably asked yourself: “How many apprentices can a licensed plumber have in Illinois?” It’s a critical question, especially if you’re running a plumbing business or planning to expand your team. Getting this wrong could mean fines, legal trouble, or even license suspension. But don’t worry—we’ve got you covered with clear, up-to-date guidance based on Illinois state law and industry best practices.
What Does Illinois Law Say About Apprentice Supervision?
In Illinois, plumbing is regulated by the Illinois Department of Public Health (IDPH) under the Plumbing License Law (225 ILCS 320/). According to Section 320/14.5, a licensed plumber may supervise no more than two (2) registered apprentices at any one time.
This rule exists to ensure that apprentices receive proper hands-on training and oversight—critical for both safety and skill development. Overloading a licensed plumber with too many trainees can compromise work quality and violate public health standards.
Key Takeaway: The legal limit is 2 apprentices per licensed plumber, regardless of the size of your company or job site.
Why Is There a Limit on Apprentice Supervision?
You might wonder why Illinois enforces such a strict ratio. The answer lies in safety, quality control, and workforce development:
- Safety: Plumbing involves working with pressurized systems, gas lines, and sewage—all of which pose serious risks if handled improperly.
- Skill Transfer: Effective mentorship requires one-on-one attention. A 1:2 ratio ensures apprentices learn correctly from day one.
- Regulatory Compliance: The IDPH aligns with national standards, including those from the U.S. Department of Labor’s Office of Apprenticeship, which emphasizes structured, supervised training.
According to a 2023 report by the National Association of Plumbing-Heating-Cooling Contractors (NAPHCC), states with stricter apprentice-to-journeyman ratios report 27% fewer code violations on residential plumbing inspections.
Who Qualifies as a “Licensed Plumber” in Illinois?
Not every plumber can supervise apprentices. Only individuals holding a valid Illinois Journeyman or Master Plumber license are authorized to oversee registered apprentices.
Here’s a quick breakdown:
| License Type | Can Supervise Apprentices? | Max Apprentices Allowed |
|---|---|---|
| Apprentice | ❌ No | 0 |
| Journeyman Plumber | ✅ Yes | 2 |
| Master Plumber | ✅ Yes | 2 |
Note: Even master plumbers—despite their advanced credentials—are still limited to two apprentices under current Illinois law.
For more background on licensing tiers, see the Wikipedia page on plumbing licenses in the U.S..
How to Register an Apprentice in Illinois
If you’re a licensed plumber ready to take on apprentices, follow these steps:
- Verify Your License Status: Ensure your Illinois plumbing license is active and in good standing via the IDPH License Lookup.
- Enroll the Apprentice: Submit an Apprentice Registration Application through the IDPH. Both you and the apprentice must sign it.
- Provide Proof of Employment: Include a letter confirming the apprentice will work under your direct supervision.
- Submit Required Fees: As of 2026, the registration fee is $50 per apprentice (subject to change).
- Maintain Records: Keep logs of training hours, tasks performed, and evaluations. The IDPH may audit these.
Apprentices must also be enrolled in an approved plumbing education program (e.g., through a trade school or union), completing at least 144 hours of classroom instruction annually alongside 2,000+ hours of on-the-job training.
Common Mistakes Plumbers Make with Apprentices
Even experienced professionals sometimes slip up. Here are frequent compliance errors:
- Exceeding the 2-apprentice limit by “informally” training unregistered helpers.
- Failing to register apprentices with the IDPH, assuming on-the-job learning is enough.
- Assigning complex tasks (like gas line installation) to apprentices without direct supervision.
- Not documenting training hours, leading to rejection of license upgrade applications later.
Remember: Unregistered workers do not count as legal apprentices, and using them as such can trigger penalties of up to $1,000 per violation.
What Happens If You Break the Rules?
The IDPH takes violations seriously. Consequences may include:
- Fines ranging from $500 to $5,000
- Suspension or revocation of your plumbing license
- Mandatory retraining or probationary status
- Ineligibility to sponsor future apprentices for 1–3 years
In 2024, the IDPH issued 42 enforcement actions against plumbing contractors for apprentice supervision violations—up 18% from 2022, signaling increased scrutiny.
Can Multiple Licensed Plumbers Share Apprentices?
Yes—but with caveats.
If your company employs multiple licensed plumbers, each can supervise up to two apprentices. However, an individual apprentice must be assigned to one primary supervisor for registration and evaluation purposes.
For example:
- A plumbing firm with 3 licensed journeymen can legally employ up to 6 registered apprentices.
- But one apprentice cannot be “shared” between two supervisors on paper—it creates accountability gaps.
Best practice: Assign each apprentice a dedicated mentor and rotate job-site exposure only under coordinated supervision.
FAQ Section
Q1: Can a master plumber in Illinois supervise more than two apprentices?
No. Despite higher credentials, Illinois law caps all licensed plumbers—journeymen and masters—at two registered apprentices each.
Q2: Do part-time apprentices count toward the limit?
Yes. Whether full-time or part-time, any registered apprentice counts toward your two-apprentice maximum.
Q3: What if I need more help on a big job?
You can hire additional licensed journeymen or helpers, but only registered apprentices count toward the 2-person limit. Helpers (unlicensed laborers) don’t require registration but cannot perform plumbing work—only assist with prep or cleanup.
Q4: How long does an apprenticeship last in Illinois?
Typically 4 to 5 years, including 8,000+ hours of on-the-job training and 576+ hours of classroom instruction.
Q5: Can I supervise apprentices remotely?
No. Illinois requires direct, on-site supervision. The licensed plumber must be physically present when the apprentice performs plumbing tasks.
Q6: Where can I find official Illinois plumbing apprentice forms?
Visit the Illinois Department of Public Health – Plumbing Division: https://dph.illinois.gov/topics-services/licensing/plumbing
Conclusion
Understanding how many apprentices a licensed plumber can have in Illinois isn’t just about following rules—it’s about building a safer, more skilled workforce. By sticking to the 2-apprentice limit, maintaining proper registration, and providing hands-on mentorship, you protect your license, your reputation, and the future of the trade.
If you found this guide helpful, share it with fellow plumbers or contractors on Facebook, LinkedIn, or your local trade group! And if you’re an apprentice, make sure your supervisor is playing by the rules—your career depends on it.
Stay compliant. Stay skilled. Keep Illinois plumbing strong. 💧🔧
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