Both routes train the same trade, and neither is universally better.
A union plumbing apprenticeship is run by a United Association local through its JATC; a non-union — merit shop — apprenticeship is run by an individual contractor or an association such as ABC or PHCC.
Both can be registered, both pay you while you train, and the same federal standards apply.
Here is how they actually differ: getting in, pay, and the work.
How union and non-union plumbing apprenticeships differ
The union route belongs to the United Association's locals.
Each local runs its own registered program through its training committee — the JATC — and the UA says its apprenticeships are registered with the U.S. Department of Labor, typically last five years, and cover tracks in plumbing, sprinkler fitting, pipefitting, HVACR, steamfitting and welding.
For scale, the UA represents approximately 409,000 plumbers, pipefitters, sprinkler fitters, HVACR service technicians, welders and pipeliners across North America.
Our guide to union plumbing apprenticeships covers that route in depth; this page stays on the comparison.
The non-union route — which contractors call the merit shop — is run by individual contractors and contractor associations instead of a union.
ABC (Associated Builders and Contractors) describes itself as founded on the merit shop philosophy and reports more than 24,000 members.
PHCC (Plumbing-Heating-Cooling Contractors Association) delivers apprenticeship content through an online learning academy, and its Educational Foundation is an EPA-approved 608 certifying program.
Which chapters run registered plumbing programs is decided chapter by chapter, so availability near you is a question for your local chapter or the contractors in your area.
One correction worth making, because search results get it backwards: MCAA (Mechanical Contractors Association of America) is not merit shop.
It partners with the United Association, and its PCA subsidiary represents union plumbing contractors.
What does not differ is the registration layer.
Any registered program — union or not — is listed by the DOL Office of Apprenticeship or a recognized State Apprenticeship Agency, and the same federal standards apply: at least 2,000 hours of on-the-job learning, plus 144 hours of related classroom instruction a year, which DOL recommends rather than requires.
Program terms can be time-based, competency-based, or a hybrid, on either side.
How you get in: JATC windows vs. applying to the contractor
The entry paths are shaped by who sponsors the program.
A union apprenticeship admits through a local JATC: you apply while that local's window is open, and the local runs its own screening and interviews — the specifics are set locally.
A merit shop plumbing apprenticeship is sponsored by the contractor or association running it, so you apply to that employer or program directly.
The federal floor is identical either way.
A registered apprentice must be at least 16 years old unless a higher minimum is set by law; there is no federal maximum age, and registered programs may not discriminate against applicants aged 40 or older.
Sponsors can add qualifications of their own on top.
Whichever route you take, you also start as a probationary apprentice: a registered program's probationary period cannot exceed 25 percent of the program's length or 1 year, whichever is shorter, and probation counts toward completion.
The application paperwork itself — documents, transcripts, timelines — works the same on both sides of the line.
Our guide to how to get a plumbing apprenticeship covers the process every route shares.
Confirm each program before you commit
Pay and benefits while you train
You are a paid employee on both routes.
In every registered program, apprentices must be paid a progressively increasing wage schedule tied to skill, and the entry wage may not fall below the federal minimum wage where it applies.
The federal rule sets no percentage steps — the raise ladder lives in each program's standards, whether a JATC's or a merit shop sponsor's.
Ask for the wage schedule in writing before you accept either.
Benefits follow the same logic.
A union apprentice's package comes out of the local's agreements; a merit shop apprentice's is whatever the sponsoring employer provides.
What we cannot give you is the comparison search results promise: a verified national figure for how much more one route pays than the other.
Our research found no such number, and pages that quote one are guessing.
What does exist is the trade-wide picture: our plumbing apprentice salary page and apprentice plumber pay guide show what apprentices earn, and the plumber salary tables show the journeyman-level endpoint both routes train toward.
The kind of work you train on
Union apprentices train in the UA's tracks — plumbing, sprinkler fitting, pipefitting, HVACR, steamfitting and welding — under the local's agreements with its signatory contractors; MCAA's PCA subsidiary represents union plumbing contractors in partnership with the UA.
Merit shop apprentices train under the contractor or association program that sponsors them: ABC's members are merit-shop contractors, and PHCC's are plumbing-heating-cooling contractors.
The registered standards govern the skills either way — what differs is which employers you train under.
Structure varies by program, not by union status.
A program's terms may be time-based, competency-based, or a hybrid, and its standards must state a numeric apprentice-to-journeyworker ratio so supervision keeps pace with training and safety.
So compare the programs in front of you individually rather than by union status alone.
On the mix of work — service calls versus new construction, residential versus commercial — our research did not confirm that one route always means one sector; ask each program what its apprentices actually spend their days doing.
Which is right for you?
Both routes are established, and neither owns the trade.
In 2025, 16.4 percent of employed wage-and-salary workers in construction and extraction occupations were union members, with 17.4 percent represented by a union; in installation, maintenance and repair occupations, 12.5 percent were members; in the construction industry, 11.1 percent.
BLS's table covers groups that broad — it publishes no membership rate for plumbers alone, so any stat quoting a precise share for the trade is not from BLS.
Since neither route is universally better, the decision comes down to the specific programs available to you.
Ask each one — union or merit shop — the same questions:
- Is the program registered, and with which agency — the DOL Office of Apprenticeship or a state apprenticeship agency?
- What is the written wage schedule, and when does each step up come?
- What work will I train on, and who are the sponsoring contractors?
- What does completion earn me — and what does my state licence require on top?
That last question matters on both routes: completing a registered apprenticeship earns a certificate from the registration agency, and it is not a trade licence.
Plumbing licensing is a separate layer, set by states and in some places by cities and counties, so confirm your state's requirements with the licensing board whichever route you choose.
Career information, not legal or financial advice. Program registration, wage schedules and entry rules are set by each sponsor under federal and state rules — confirm the details with the program and, for licensing, with your state licensing board or the city or county where licensing is local.