Union plumbing apprenticeships are run by the United Association's local unions, not by the UA's national office.
You get in by applying to a local's own training program — its JATC — while that local is taking applications.
UA apprenticeships are registered with the U.S. Department of Labor, typically last five years, and pair paid on-the-job training with classroom instruction.
Each local sets its own windows, screening and pay steps; here is how the process works.
How UA plumbing apprenticeships work
The United Association is the international union; its local unions run the apprenticeships.
The program you apply to belongs to a local — its training committee, which you will see called the JATC — and that program is registered with the U.S. Department of Labor.
If you are still getting oriented, our explainer of what the UA is covers the union's structure and how its locals work.
Registered is the load-bearing word.
Registered programs are listed either by the DOL's Office of Apprenticeship or by a recognized State Apprenticeship Agency acting for DOL, and the UA says its apprenticeships are registered with DOL and the corresponding Canadian authorities.
The shape of the program is earn-while-you-learn.
UA apprenticeships typically last five years, with tracks in plumbing, sprinkler fitting, pipefitting, HVACR, steamfitting and welding.
Apprentices are paid employees from the start: the UA describes its registered apprenticeships as including 2,000 hours of paid on-the-job training per year plus 216 hours of related classroom instruction, though the UA's page does not say whether the classroom figure repeats each year, so treat it as a program detail to confirm.
The pattern matches the trade at large — BLS says most plumbers, pipefitters and steamfitters learn the trade through a 4- or 5-year apprenticeship with about 2,000 hours of paid on-the-job training per year plus technical instruction.
Classroom work runs alongside the job.
DOL recommends at least 144 hours of related technical instruction per year of apprenticeship — a recommendation, not a federal requirement.
Each program's standards set what it actually asks for.
New apprentices also start on probation: a registered program's probationary period cannot exceed 25 percent of the program's length or 1 year, whichever is shorter, and time served on probation counts toward completion.
For scale: union membership is a real but minority share of these trades.
In 2025, 16.4 percent of employed wage-and-salary workers in construction and extraction occupations — the group that contains plumbers, pipefitters and steamfitters — were union members, with 17.4 percent represented by a union.
In installation, maintenance and repair occupations, the group that contains HVAC mechanics, 12.5 percent were members.
BLS's table covers occupation groups that broad; it publishes no membership rate for plumbers alone.
Requirements to apply
Every registered apprenticeship shares one federal floor: an apprentice must be at least 16 years old unless a higher minimum is set by law.
There is no federal maximum age, and the anti-discrimination rules for registered programs specifically protect apprentices and applicants aged 40 or older.
Beyond that floor, program sponsors — including union JATCs — may set other qualifications of their own.
The baseline for the trade itself, per BLS: a high school diploma or equivalent is typically required to become a plumber, and some plumbers attend a vocational-technical school before starting on-the-job training.
Note the direction of that sentence — the apprenticeship is itself the training route for most, not something you finish school to unlock.
What each local adds on top of the floor is where applicants get surprised.
Requirements differ from local to local, and the list printed on one local's flyer is not your list — the one in your local's standards is.
The practical move is to ask, ideally in writing:
- The local's minimum requirements — age, education, and anything else its standards list
- Which of the UA's trade tracks it trains and takes applications for
- When its next application window opens, and what documents it wants
- A copy of its program standards — wage schedule included — before you commit
If you are still weighing the union route against the others — merit-shop contractors, trade school, employer-sponsored programs — our guide to how to get a plumbing apprenticeship covers the application process every route shares.
The rest of this page stays on the union specifics.
Requirements are local — confirm with the JATC before you apply
The aptitude test and interview
Search for the plumbers union aptitude test and you will find prep courses describing a single, national exam.
We could not confirm that a single national exam exists.
Aptitude testing, application windows and pay steps are set by each local JATC, and our research did not confirm a standard UA-wide test format, section count or pass mark — so any page quoting "the" UA test with confidence is most likely describing somebody's local, not a union-wide rule.
What holds across programs is the sequence rather than the content: a local opens applications for a window, screens its applicants — which may include an aptitude test — and interviews the ones it advances before selecting its next class.
Where locals differ is everything specific: whether a given local tests at all, what its test covers, how it is scored, what happens if you need to retake it, and how much the interview counts.
Those answers live with the local, not with us.
Two practical rules follow.
First, prepare from the local's own materials: if the JATC publishes a study guide or names the subjects it tests, that list outranks any generic prep syllabus.
Second, ask your local what its screening involves before you pay for any course sold as preparation for the union test — it may point you to its own materials instead.
Confirm the calendar the same way.
Application windows are set locally, so the schedule you read about online may not be your local's.
Ask when the next window opens, how long it stays open, and what the local does between intakes.
Ask before you prep
How applicants are ranked
How a local turns its applicant pool into its next apprentice class is also a local matter, and our research did not confirm a national ranking formula.
What we can give you is the structure that shapes the selection and the questions that get you real answers.
The structural fact is the ratio.
Registered program standards must state a numeric apprentice-to-journeyworker ratio, set consistently with proper supervision, training, safety and continuity of employment.
The federal rule sets no specific number — each program's standards do.
That ratio bounds how many apprentices a program can carry at once, and intake timing and class size are therefore local decisions.
Why a given local's window opens when it does — how much the work available to its signatory contractors shapes the timing, for instance — is not something our research confirmed; ask the local how it schedules intake.
The rest of the ranking mechanics are the local's own.
When you contact a JATC, these are the questions worth asking, because none of them has a national answer:
- How applicants are ordered or scored
- How long an application or test score stays active, and whether you must reapply
- Whether prior trade experience or schooling counts for anything
- What its probationary period means for a new apprentice
Each question gets you a concrete answer from the only program that will actually rank you.
And while a local's window is closed, contractors across both trades still hire entry-level workers directly — our plumbing apprentice job listings show who is hiring now.
Pay and benefits while you train
You are paid from your first day, because the on-the-job hours are paid employment.
The raises are structured too: registered programs must pay apprentices a progressively increasing wage schedule tied to skill, and the entry wage may not be below the federal minimum wage where it applies.
Note what the federal rule does not do — it sets no percentage steps.
Each program's own standards set the raise ladder: when it steps up, and by how much.
That absence matters because blanket figures — union apprentices earn a fixed percentage of journeyman scale, everywhere, always — are exactly that: blanket.
The real schedule for your local is in its standards.
Ask the local for a copy of its current standards and wage schedule — ideally in writing — before you accept an offer, along with the classroom obligation that comes with it.
The other half of union compensation is the package around the wage.
What an apprentice qualifies for, and when eligibility starts, is set by the local's own agreements — ask the JATC what its current agreements provide for apprentices rather than assuming a national package.
Veterans have a documented layer on top: the Post-9/11 GI Bill pays a housing allowance to veterans in registered apprenticeships, stepping down as the program progresses — 100 percent of the E-5-with-dependents BAH rate for months 1 through 6, 80 percent for months 7 through 12, 60 percent for months 13 through 18, 40 percent for months 19 through 24, and 20 percent after 24 months.
Confirm current rates with the VA and ask the program how to use your benefits.
For the numbers behind the ladder, our plumbing apprentice salary page compiles the BLS figures for the role, and the plumber salary tables show the journeyman-scale context apprentices are working toward.
Career information, not legal or financial advice. Apprentice wage schedules, benefits, eligibility rules and application processes are set by each local's program under federal and state rules. Confirm the details that matter to you with your local's JATC, and check licensing questions with your state licensing board or the city or county where licensing is local.