State by state, sometimes city by city — never federal. That's the honest starting disclaimer for every trade in this network, and plumbing is no exception. Here's the general pattern, backed by real state examples.
The General Pattern
Plumbing licensing is near-universal and heavily code-driven, administered mostly at the state level (a handful of states delegate to municipalities). Exams test whichever plumbing code the state has adopted, plus state and local amendments.
| Tier | Typical Requirement | What It Grants |
|---|---|---|
| Apprentice | Registration while training | Legal work under supervision |
| Journeyman | Completed apprenticeship hours + exam | Independent work under a licensed contractor |
| Master | ~2 additional years + exam | Permits, supervision, contracting eligibility |
Three States, Three Different Numbers
Texas (TSBPE)
Requires 8,000 hours of experience plus a 48-hour approved training course (or enrollment in a DOL-registered program) to sit for the journeyman exam. Exam fee: $40. Initial license fee: $40.
Michigan
Requires 6,000 hours over at least 3 years for the journeyman license. The exam is 125 questions, requiring a 70% pass rate. Master license fee: $300.
Iowa
Requires a full four-year DOL-registered apprenticeship and passing the journeyperson exam — exam-approval fee $35 plus a $99 testing fee.
Same trade, same code family, three states, three genuinely different hour and fee structures. "How long does it take to get licensed" only has an answer once you specify which state.
The Code Divide: UPC vs. IPC
Which code your state tests changes what you study, not just where you work. The Uniform Plumbing Code (UPC) governs in most western states; the International Plumbing Code (IPC) governs in most eastern and central states. Full breakdown: UPC vs. IPC.
Substituting Experience for Formal Apprenticeship
Some states allow documented work experience to substitute for part of a formal apprenticeship — genuinely useful for career-changers coming from adjacent mechanical or construction work, but the specifics (how many years, what qualifies as documentation) vary enormously by state board. Never assume; always confirm directly.
Master Plumber and Specialty Endorsements
Beyond the standard tiers, many states offer specialty endorsements — medical gas, backflow prevention, water supply protection — each with its own exam and typically commanding a pay premium (specializations covered here).
How to Verify Your State in 15 Minutes
- Search "[your state] plumbing licensing board" — .gov result only.
- Confirm hour requirements, exam structure, and which code (UPC/IPC) is tested.
- Check continuing-education requirements for renewal.
- If relocating, verify reciprocity directly with both state boards — never assume a license transfers.