It depends on the state.
Whether you must register before doing paid plumbing work is decided where you live — by the state plumbing board, or by the city or county where licensing is local.
Texas, Louisiana, Maryland, Massachusetts, Michigan, North Dakota and Illinois make plumbing apprentices register or hold an entry-level license; Delaware is the opposite — apprentices work unlicensed under a master plumber.
Here is what an apprentice plumbing license or registration requires, and how hours start counting.
Which states require apprentice registration?
Two different registrations get called "apprentice licensing," and it helps to separate them.
The first is the apprenticeship program's registration with the U.S. Department of Labor's Office of Apprenticeship or a recognized State Apprenticeship Agency — DOL's recognition list (read September 29, 2026) places 31 jurisdictions under state agencies, with the federal office registering programs in the rest.
That registration belongs to your sponsor, not to you.
The second is the plumbing board's apprentice license or registration — a permission issued to you before you do plumbing work.
That one is what this page is about.
Massachusetts shows both layers: the Division of Apprentice Standards registers the training program, while the Board of State Examiners of Plumbers and Gas Fitters licenses the apprentice plumber.
Louisiana works the same way — an apprentice in a Louisiana Workforce Commission-approved program must also register with the State Plumbing Board.
The boards our research confirms require plumbing apprentices to register or hold an entry-level license:
- Texas — a Plumber's Apprentice registration with the Texas State Board of Plumbing Examiners.
- Louisiana — every unlicensed person doing plumbing or gas fitting must register as an apprentice with the State Plumbing Board of Louisiana, be in the employ of a master company and work under a journeyman or master.
- Massachusetts — apprentice plumber licenses come from the Board of State Examiners of Plumbers and Gas Fitters.
- Maryland — the Maryland State Board of Plumbing licenses Apprentice Plumber/Gas Fitters, and apprentices must be at least 16.
- Michigan — plumbing apprentices register with LARA as Apprentice Plumbers, regardless of program.
- North Dakota — every apprentice plumber must register with the state plumbing board within 30 days of beginning apprenticeship.
- Illinois — the state's two levels are the licensed apprentice plumber and the licensed plumber.
Treat that list as where the requirement is confirmed, not a census of every state — and the counter-model exists.
Delaware licenses only masters: apprentices and journeymen there work unlicensed, under the supervision of a master plumber who employs them or works full time for the same business.
The apprentice rung also sits at the bottom of a ladder that changes at every border; our guide to plumbing license requirements walks the whole ladder.
What can a plumbing apprentice legally do?
The registration is permission to learn the trade under supervision — not to work alone.
Texas draws the line in the rule itself: a Plumber's Apprentice may perform plumbing only under direct supervision, which the board defines as a TSBPE licensee being on the job site at all times the plumbing work is happening.
Louisiana's version: all work under the direct, on-the-job supervision of a journeyman or master, while in the employ of a master company.
And Michigan enforces the gate — you are not allowed to be on the job site without an active registration.
How many apprentices one plumber may supervise is written down twice.
Your program's standards must state a numeric apprentice-to-journeyworker ratio consistent with proper supervision, training, safety and continuity of employment — the federal rule requires the number to exist but sets no specific figure.
State licensing laws often set their own, so the binding ratio where you work can be the stricter of the two.
What the registration does not do is promote you.
Every pipe you fit is supervised experience on the way to the journeyman exam.
For what the job itself involves — the duties, the pay, the sponsors — see our plumbing apprentice career guide.
How do you apply for and renew an apprentice registration?
You apply for an apprentice plumbing license — or an apprentice registration; states use both words — with the state board named above, before your first day of plumbing work.
The paperwork is a short application, a fee and an age floor: Texas requires apprentices to be at least 16, and Maryland sets the same minimum.
Fees and renewal cycles are board-specific.
Texas: $15 to register, renewed for $15 a year.
Louisiana: $20 by check or money order, renewed every year by December 31, with no continuing education required of apprentices.
Maryland: $18.50, with renewals at the same $18.50, on a fee schedule updated July 1, 2025.
Massachusetts: apprentices are exempt from the 12 clock hours of continuing education licensed plumbers owe each two-year cycle.
Michigan's rule is the practical summary — keep the registration active, because you are not allowed to be on the job site without one.
Renewal is not a formality forever.
Maryland caps the apprentice license at two consecutive renewal cycles — after that, the holder must take the journey exam.
In Texas, a plumbing license that has been expired for more than two years cannot be renewed at all: the person must start over as a registered apprentice and re-pass the exams.
Fees and rules change — confirm with your board
How do apprentice hours count toward the journeyman exam?
Register before your first hour, because in the registering states the clock starts at registration.
Texas counts plumbing experience toward the Tradesman or Journeyman exam only after the worker is registered with TSBPE as a Plumber's Apprentice.
North Dakota is blunter: hours worked before registration do not count.
The hour totals you are logging toward are the board's, set state by state.
Texas: 4,000 hours for the Tradesman Plumber-Limited exam, 8,000 for Journeyman.
Maryland: 7,500 hours under a licensed master plumber, plus holding the apprentice license for at least 4 years, plus 32 hours of backflow prevention device testing training, plus the written exam.
Massachusetts: 6,800 clock hours as a licensed apprentice, plus 550 clock hours of plumbing and gasfitting theory over no less than four years, credited at no more than 165 hours per year.
Louisiana: 7,000 hours for an indentured apprentice or 8,000 for an unindentured one.
A registered apprenticeship feeds the same goal from two directions.
Its on-the-job component has a federal floor of at least 2,000 hours of on-the-job learning — but those program hours and the board's exam hours are two different ledgers, so keep both.
The apprenticeship can replace coursework: in Texas, enrolment in or completion of a DOL Office of Apprenticeship program exempts a candidate from the 24-hour Tradesman or 48-hour Journeyman training course.
What it does not replace is the license: finishing a registered apprenticeship earns a completion certificate from the registration agency — a record of a finished apprenticeship, not a plumbing license.
When the term ends, the next step is the journeyman plumber exam your board runs.
Career information, not legal advice. Licensing requirements change; confirm the current rules with your state licensing board, or the city or county office where licensing is local, before you apply, renew or count hours.