What interview questions should you ask a journeyman plumber? (with good answers)
A question bank for owners and service managers hiring on the journeyman rung: technical questions with the answers to listen for, customer and behavioural questions, a practical task, red flags and a scoring method.
A journeyman plumber interview needs three kinds of questions: technical questions with right answers that test journey-level judgment, customer and behavioural questions that show how the candidate runs a ticket, and a practical task performed in front of you.
This page gives you the bank for each — the answer a competent journeyman should give, the red-flag replies, and a scoring sheet that keeps candidates comparable.
Before the interview
Write the questions before the candidate is in the room — and write them from your own job description.
The duties you posted are the test blueprint: for a journeyman hire that means solo service work, permitted installations, inspection pass-offs and whatever supervision you expect over helpers.
Before an offer you may ask about an applicant's skills, education, work history and required certifications and licences, and you may ask them to describe or demonstrate how they would do the job's tasks — that is exactly what the technical and practical sections below do.
If the posting is not written yet, start from our journeyman plumber job description template and build the question sheet from it.
State the job's physical requirements and ask whether the candidate can meet them.
The EEOC's own examples are the ability to lift a certain amount of weight and the ability to climb ladders.
If your plumbing work means crawl spaces, trenches or heavy fixtures, the same applies — say what your trucks demand and ask the question directly; that is allowed.
What you may not do before a conditional offer is ask disability-related questions or require a medical examination.
Keep the off-limits subjects off the sheet, the phone screen and the small talk.
Before an offer, no questions about past job injuries or workers' compensation history — "ever hurt your back under a house?" stays out of the pre-offer conversation.
You may ask about current illegal drug use, but not about lawful prescription medication.
Salary history is its own trap: it is banned where state law says so, and the jurisdictions this research verified are Virginia, Hawaii, Rhode Island, D.C. and California — with other states unchecked, so treat that as a floor rather than the full map.
The safe habit anywhere: post the pay range and ask what the candidate is looking for.
Size decides which rules bind you.
Federal EEO laws — Title VII and the ADA — cover private employers with 15 or more employees; the age discrimination law (ADEA) covers those with 20 or more; the Equal Pay Act covers virtually all employers.
A shop with 4 to 14 employees is still covered by the Immigration Reform and Control Act's ban on national-origin and citizenship discrimination, which the U.S. Department of Justice enforces.
State laws often reach smaller employers than the federal ones, so check your state's rules too.
Then run the same questions, in the same order, for every candidate.
You will compare answers fairly, and your notes will still make sense when the last interview of the week is done.
The full sequence around this interview — sourcing, licence verification, pay, onboarding — is our guide to how to hire a journeyman plumber; this page picks up at the interview itself.
Which technical questions test real journeyman plumber skill, and what are good answers?
You open a ceiling for a repipe and the framing doesn't match the print. What do you do before you pipe it?
What to listen for: The work stops before the pipe comes off the truck: back to the drawing, then a conversation — with the contractor or homeowner, and with the inspector where the route touches code. 'I'd make it fit' is a helper's answer; the journeyman answer treats an undocumented deviation as the company's problem at inspection time.
Strong candidates also put a cost on the ambiguity — days and a revisit, not just inches.
The inspector fails your rough-in. Walk me through the rest of that week.
What to listen for: The correction list read as the scope of work: fix what's on it, ask the authority having jurisdiction about anything unclear instead of arguing from memory, schedule the re-inspection, and tell the customer straight.
Local plumbing code can differ from the model code, and a strong candidate defers to the local inspector rather than quoting a memorized rule.
The red flag inside this answer is any version of 'inspectors around here don't really check.'
A customer has a rocking toilet and a stain spreading on the ceiling below. Diagnose it for me.
What to listen for: An order of checks: pull the toilet, inspect the flange and the seal at its base, look at the subfloor around it, and rule out the supply and the drain above before blaming the ceiling on anything.
A journeyman separates the three suspects — failed seal, failed flange, water from another level — and prices the fix to the finding. 'New wax ring, no matter what' is the guess that generates your callback.
You've got a green helper on the truck and a rough-in due. What do you hand them, and what stays with you?
What to listen for: Delegation with a boundary: measuring, hauling, hanging strap, second-account work — with every joint and connection checked before the wall closes.
The boundary is the answer: whatever the licence's scope reserves, the final check, and anything the permit covers, stays with the journeyman.
A candidate who hands a helper the whole rough-in unsupervised is describing your next inspection failure.
Take me through getting your journeyman card — what it took, and what you could run the day after you had it.
What to listen for: The issuing board — or the city or county, where licensing is local — named without hesitation, the exam described in first person, and the part that matters to you: the scope change, what they could do unsupervised the day they held it that they couldn't the day before.
If their exam had a practical or drawing component, a real taker remembers it unprompted.
Whatever they claim, verify it against the issuer's own record — never a photo of the card.
A drain you rerouted needs to cross a joist bay too shallow for the fall it needs. What are your options?
What to listen for: Honesty about constraints: the fall is a code matter, not a feel call, and the structure is not theirs to cut on their own authority — so the options are reroute, rework the layout, or take the question to the contractor and the code official, before anything is cut.
Strong answers name the trade-off and hand the decision to whoever owns it. 'I'd notch it and sister it back' decided alone is how a floor structure ends up on your invoice.
Which customer and behavioural questions matter most?
A customer refuses the replacement you recommend and wants it patched. What do you say, and what do you write down?
What to listen for: Plain-language risk explained once, without scare tactics; the customer's decision respected; and the paperwork volunteered — what was recommended, what was declined, what was signed.
A journeyman protects the company twice on this call: once by documenting, once by leaving the relationship intact for the next visit.
Listen for contempt in the telling — resentful recommendations become your reviews.
Tell me about a job where the scope grew once you opened things up. How did the price conversation go?
What to listen for: Stop-and-price discipline: photos, options with prices, approval before the extra work proceeds.
Your journeyman runs the ticket, so the extra-work price conversation is theirs to have — and the ones you want treat a change order as customer service rather than an ambush.
A candidate who 'just did the work and put it on the bill' is handing you the dispute that outlives the job.
Tell me about a helper or apprentice you trained. What did you hand them, and how did you check their work?
What to listen for: A specific person and a specific method — show one, watch one, check everything that touches the permit.
On your trucks, this is the tier that trains the helpers, so how the candidate talks about teaching tells you how your own standards will travel. 'They pick it up or they don't' is a no-hire answer on a truck that runs helpers.
You're on call and a burst supply line, a backed-up restaurant and a no-water call land inside the same hour. What happens next?
What to listen for: Triage out loud: active damage first, then the business that can't operate, then the no-water call — with the other customers called and given real windows instead of silence.
Then the honest part: the point at which they escalate to the dispatcher or owner rather than promise coverage they don't have.
A hero who 'took them all' is a burnout and a missed-appointment generator.
Where does the next licence rung fit in your plan — the master tier, or whatever your state calls it?
What to listen for: A real answer about the next rung: exam prep, bigger scope, running crews.
You are listening for ambition you can attach to a retention path. 'I'm good where I am' is a legitimate answer too — but a candidate who has never thought about the next tier may have stopped following the code as well.
What practical task should a journeyman plumber candidate do?
Run a mock service call on our training rig — diagnose it, price it, and explain both to me as the customer.
What to listen for: The whole ticket in miniature: questions before conclusions, a diagnosis explained in plain language, a price stated without apology, and a check-back at the end — 'what questions do you have for me?'
This one task tests the technical and customer groups at once, and it is the closest an interview gets to a first day on a truck.
Here's the print for a two-bath rough-in. Don't mark the run — tell me what you'd want to know before rough day.
What to listen for: Print literacy plus planning: fixture rough-in locations, joist direction and depth, where the water heater lands, what the inspector will want to see at rough.
You are not testing whether they can draw the pipe — you are testing whether they find the ambiguities before the crew is standing on the job.
A candidate with no questions has either not read it or has never run one.
We've seeded a fault in this assembled lavatory and supply mock-up. Find it — then tell me what you'd tell the customer.
What to listen for: An isolation order you can follow: what they rule out first, what check changes their mind, and whether they can say 'I need to open this to confirm' instead of pointing and guessing.
Then the translation — the fault explained to a layperson, with a price and no jargon.
Hands and explanation back to back tell you whether the trade knowledge and the customer skills belong to the same person.
Pressure-test this assembly and narrate what you're doing while you do it.
What to listen for: The narration is the point: what they are testing, what a pass looks like, what they do on a fail, and who signs off before the wall closes.
A candidate who has stood next to an inspector and answered for a system tends to narrate; one who has only watched often goes quiet.
You are listening for sequence and sign-off, not for figures recited.
Which answers are red flags?
None of these is an automatic no on its own — but each should stop the interview long enough to check, and a couple should end it.
- A licence the candidate can't source. They say 'journeyman' but can't name the board, city or county that issued it or what the exam covered. You verify the card through the issuer's own record, so an unsourced licence cannot be checked before you offer.
- No answer on scope. Ask what they may run unsupervised and what needs a master or another licence tier, and get a shrug. On this hire the supervision boundary is the licence — hedging it is how unpermitted work lands under your company's name.
- Contempt for permits and inspections. 'We never pulled one' or 'the inspector never looked' — said as a boast. In jurisdictions that require permits, that habit becomes your liability the day the hire pulls one under your company's name.
- Guess-first stories. Every story ends 'so I replaced it and the problem went away' with no isolation step in between. You pay for the parts, the callback and the customer's patience.
- The hands-off helper story. Talks about running green helpers with no training method and no check — 'they figure it out.' Your standards don't travel on that truck, and neither does your warranty.
- Every past employer is a villain. One bad shop is a story; a row of them is a pattern. Ask what each owner would say about the candidate's work, then call and compare.
- Dodges the practical task. Too busy, does this every day, let's skip to the offer — from a hire you are counting on to work unsupervised, refusing to demonstrate is its own answer.
- Side work on your truck. Casually describes using your materials, your van or your company's name for after-hours jobs. However good the hands, this is the behaviour your other techs will copy.
After the interview
Score the same day, on the same sheet.
One row per group — technical answers, customer answers, the practical task, credentials — each on a 1-to-5 scale, with a line of notes on the strongest and weakest answer of the day.
Score before the next candidate sits down: memory grades on charm.
Ask every candidate the same questions in the same order — that is what makes the scores comparable.
Consistent questions and a written sheet also give you a record of how each candidate was judged.
Under the Uniform Guidelines on Employee Selection Procedures, a hiring test that has adverse impact on a race, sex or ethnic group is treated as discriminatory unless it has been validated.
So if you take the practical task out of the conference room and onto real work — a paid working interview for HVAC and plumbing techs — or you score candidates on a formal skills test, have an employment attorney review how you run it first.
Weight the rows for your trucks before the first interview, not after the first offer.
A service-and-repair shop leans on the diagnostic-sequence and customer-explanation answers; a remodel or repipe crew leans on the print-reading and bench tasks.
Same sheet, different weights — decided in advance, so the sheet decides the hire instead of the other way round.
Verify through the source, then close out the checks in the legal order.
Confirm the licence through the issuer's own record — the board's public lookup for a state licence, or the city or county where licensing is local; our guide to verifying licences has the steps — and take the references by phone.
After a conditional offer, you may ask disability-related questions and require medical examinations, as long as you do it for all entering employees in that job category.
If your background check comes from a screening company, the Fair Credit Reporting Act's notice and adverse-action steps apply, and the EEOC expects a targeted criminal-record screen — one that considers at least the nature of the offense, the time elapsed and the nature of the job.
When the sheet says yes, make sure the posting that found them still says the right things — and browse journeyman plumber jobs to see the board the way candidates see it.
This page is employer career information, not legal advice. Federal interview rules are enforced by the U.S. Equal Employment Opportunity Commission. For employers with 4 to 14 employees, the national-origin and citizenship discrimination rules are enforced by the U.S. Department of Justice. State and local laws often add rules and reach smaller employers. Confirm what applies to your company with your state's agencies and an employment attorney.
More hiring resources
Interviewing journeymen? Post the opening too.
Licensed journeyman plumbers look for their next truck on the job board built only for the two trades.