Free plumber interview questions template with a scoring rubric: technical, behavioral, apprentice, and phone-screen kits. Built for small businesses. Download as DOCX.
6 free interview kits for hiring plumbers, plus a 1-to-5 scoring rubric to compare candidates fairly, built for small plumbing businesses hiring without HR. Download as DOCX.
Hiring a plumber is high-stakes for a small trade business, because a weak hire shows up fast as callbacks, failed inspections, and unhappy customers in their own homes. The interview is where you catch it, but only if it is structured. A friendly conversation tells you who is likeable; a set of consistent questions plus a scorecard tells you who can actually diagnose a problem, work to code, and represent your company in a customer's house.
These six kits give you exactly that: ready-made question sets for standard, technical, apprentice, behavioral, and phone-screen interviews, plus a scoring rubric that turns a good conversation into a fair, documented decision. Download them free, no email required. They pair with the plumber job description for writing the posting, and the guide to conducting an interview for running the process well.
TL;DR
Strong plumber interview questions make a candidate show real skill, not just describe it: how they diagnose a hidden leak, choose pipe materials, and work to code. Use a kit matched to the role (technical, apprentice, behavioral, phone screen), verify the license level, and score every candidate 1 to 5 on the same rubric to compare fairly. Never ask about a protected characteristic. Download six kits plus a scorecard as DOCX.
How to Use These Templates
Each kit is a structured interview: the same questions for every candidate, with space for notes and a 1-to-5 score. That structure is the point. A structured interview predicts who can actually do the job far better than a free-form chat, and it keeps your hiring fair and consistent.
Pick the kit that matches the role and stage, ask every candidate the same questions, and score the answers right after each interview while they are fresh. Then compare scorecards side by side rather than relying on who left the best impression. For a plumbing owner without an HR department, this is the difference between a confident hire and a costly guess.
Which Interview Kit Should You Use?
Pick the kit by the role and the stage of hiring. Each set emphasizes the questions that matter for that hire, and they all pair with the same scoring rubric so you can compare candidates consistently.
Standard Scorecard
First round
The all-purpose set covering background, technical, safety, and customer questions, with a 1-to-5 score column. Start here for most hires.
Technical Skills
Hard skills
Deeper plumbing-specific questions on diagnostics, materials, and code, each with a note on what a strong answer sounds like.
Apprentice / Entry
Helper or apprentice
For a first or junior hire: weighted toward attitude, reliability, and willingness to learn over experience.
Behavioral / Service
Works in homes
STAR-method questions for a service plumber: customer service, professionalism, and composure under pressure.
Phone Screen
15-minute screen
Five to seven quick questions to decide whether to bring a candidate in for a full interview.
Scoring Rubric
Compare fairly
The differentiator: a 1-to-5 scorecard across eight competencies, with an Advance / Hold / Pass recommendation.
Match the Kit to the Hire
A standard first-round interview: Standard Scorecard. Assessing hands-on skill: Technical Skills. A helper or apprentice: Apprentice / Entry. A service plumber who works in homes: Behavioral / Service. A quick first pass before bringing someone in: Phone Screen. And whichever you use, pair it with the Scoring Rubric to compare candidates on the same scale.
6 Free Plumber Interview Kits to Download
Download all six as a single Word document, or copy individual kits. Each kit includes the questions, note space, and a score column; the rubric adds a full 1-to-5 scorecard. Free, with no email required.
Download All 6 Interview Kits and the Scorecard
Standard, technical, apprentice, behavioral, phone screen, and the scoring rubric. All in one DOCX.
Kit 1: Standard Plumber Interview Scorecard
The all-purpose first-round set covering background and licensing, technical, safety, and customer questions, with a 1-to-5 score column throughout. Start here for most hires.
Standard Plumber Interview Scorecard
STANDARD PLUMBER INTERVIEW SCORECARD
Candidate: __
Role: __
Interviewer: __
Date: __
Ask every candidate the same questions and score 1 to 5 so you can compare
fairly. 1 = poor, 3 = acceptable, 5 = excellent.
BACKGROUND AND LICENSING
1. Walk me through your plumbing background and training.
Notes: __ Score (1-5): ____
2. What is your current license level (apprentice, journeyman, master)?
Notes: __ Score (1-5): ____
3. Do you have more experience with residential or commercial work?
Notes: __ Score (1-5): ____
TECHNICAL
4. Walk me through how you diagnose and fix a leak you cannot see.
Notes: __ Score (1-5): ____
5. How do you decide which pipe material to use for a job?
Notes: __ Score (1-5): ____
6. Describe a difficult repair you completed and how you approached it.
Notes: __ Score (1-5): ____
SAFETY AND CUSTOMER
7. What safety steps do you take before and during a job?
Notes: __ Score (1-5): ____
8. A customer is upset about a price or a mess. What do you do?
Notes: __ Score (1-5): ____
9. How do you handle being on call for emergencies?
Notes: __ Score (1-5): ____
CLOSE
10. Why do you want to work for our company?
Notes: __ Score (1-5): ____
11. What questions do you have for us?
Notes: __
OVERALL
Total score: ______ / 50
Strengths: __ Concerns: __
Recommendation: [ ] Advance [ ] Hold [ ] Pass
Kit 2: Technical Skills Assessment Kit
Deeper plumbing-specific questions on diagnostics, materials, code, and repairs, each paired with a note on what a strong answer sounds like so a non-plumber can evaluate it.
Technical Skills Assessment Kit
TECHNICAL SKILLS ASSESSMENT KIT
Candidate: __
Interviewer: __
Date: __
For assessing hands-on plumbing skill. Listen for specifics, correct
terminology, and safe, code-aware practices. A strong answer is concrete, not
vague. (What a strong answer sounds like is noted under each question.)
DIAGNOSTICS
1. How do you locate a hidden leak behind a wall or under a slab?
Strong answer: methodical isolation, listening or moisture tools, checks
supply vs drain, minimizes demolition.
Notes: __ Score (1-5): ____
2. A water heater is leaking from the relief valve. What is your process?
Strong answer: checks temperature and pressure, tests the valve, considers
thermal expansion and a possible expansion tank, not just a parts swap.
Notes: __ Score (1-5): ____
MATERIALS AND CODE
3. When would you use copper versus PEX versus PVC, and why?
Strong answer: matches material to application, water type, temperature, and
local code; knows PVC is not for hot supply.
Notes: __ Score (1-5): ____
4. What do you check to keep a job code-compliant and inspection-ready?
Strong answer: references local code, permits, venting, backflow prevention,
and proper slope on drains.
Notes: __ Score (1-5): ____
REPAIRS AND TOOLS
5. Walk me through clearing a stubborn main drain clog.
Strong answer: diagnoses cause, chooses snake versus hydro-jetting
appropriately, considers camera inspection, protects the property.
Notes: __ Score (1-5): ____
6. How do you handle a soldered joint that keeps leaking?
Strong answer: clean and dry, proper flux and heat, knows why a wet line
will not solder; considers press fittings as an alternative.
For a helper or apprentice: weighted toward attitude, reliability, and willingness to learn over experience. Built to assess raw potential consistently.
Apprentice / Entry-Level Interview Kit
APPRENTICE / ENTRY-LEVEL INTERVIEW KIT
Candidate: __
Interviewer: __
Date: __
For a helper or apprentice, hire for attitude, reliability, and willingness to
learn over experience. The goal is potential and work ethic.
MOTIVATION AND LEARNING
1. Why do you want to become a plumber?
Notes: __ Score (1-5): ____
2. Tell me about a time you learned a hands-on skill. How did you pick it up?
Notes: __ Score (1-5): ____
3. How do you take direction and feedback on a job site?
Notes: __ Score (1-5): ____
RELIABILITY AND WORK ETHIC
4. This work means early starts and physical days. How do you feel about that?
Notes: __ Score (1-5): ____
5. Tell me about a time you showed up and worked hard when it was tough.
Notes: __ Score (1-5): ____
6. Do you have reliable transportation and a clean, valid license if needed?
Notes: __ Score (1-5): ____
BASICS AND SAFETY
7. What basic tools or plumbing tasks are you already familiar with?
Notes: __ Score (1-5): ____
8. Why does safety matter on a job site, in your view?
Notes: __ Score (1-5): ____
9. Are you willing to enroll in an apprenticeship and study for licensing?
A 15-minute screen to decide whether to bring a candidate in: license level, experience, availability, and pay expectations, kept short.
Phone Screen (5-7 Quick Questions)
PLUMBER PHONE SCREEN (5-7 QUICK QUESTIONS)
Candidate: __
Caller: __
Date: __
A 15-minute screen to decide whether to bring the candidate in. Keep it short.
QUICK SCREEN
1. What is your license level and how many years of experience do you have?
Notes: __
2. Residential, commercial, or both?
Notes: __
3. Why are you looking for a new role right now?
Notes: __
4. What are your pay expectations for this role?
(Ask expectations, not salary history, which some states ban.)
Notes: __
5. What is your availability, and are you open to on-call work?
Notes: __
6. Do you have a valid driver's license and reliable transportation?
Notes: __
7. Any licensing or background requirements we should know about?
Notes: __
DECISION
Bring in for full interview? [ ] Yes [ ] No [ ] Maybe
Notes: __
Kit 6: Plumber Scoring Rubric and Evaluation Form
The differentiator: a 1-to-5 scorecard across eight competencies, with evidence fields and an Advance, Hold, or Pass recommendation. Use it with any kit above.
Plumber Scoring Rubric and Evaluation Form
PLUMBER SCORING RUBRIC AND EVALUATION FORM
Candidate: __
Role: __
Interviewer: __
Date: __
Score each competency 1 to 5. Use the same form for every candidate so you can
Reminder: Score only job-related skills. Do not factor in age, sex, race,
religion, national origin, disability, or any protected characteristic.
Technical Questions and Strong Answers
The hardest part of hiring a plumber, especially for an owner who is stretched thin, is judging technical answers. The trick is to listen for process and specifics rather than buzzwords. Here is what separates a strong answer from a weak one, grouped into green, yellow, and red flags you can watch for in real time.
Green flags: what a strong plumber answer sounds like
Diagnoses a problem step by step before reaching for a fix
Uses correct terms and names specific materials and methods
Talks about code, permits, and safety without being prompted
Describes a real difficult job with a clear result
Explains repairs to a customer in plain, calm language
Yellow flags: probe further before deciding
Vague answers with no specifics or terminology
Jumps straight to a parts swap without diagnosing
Cannot clearly state their license level or experience
Shrugs off safety or code as someone else's job
No questions for you and little interest in the company
Red flags: serious concerns
Badmouths past employers or customers
Describes unsafe or clearly non-code shortcuts
Is dishonest or evasive about licensing
Shows no respect for working in a customer's home
Cannot describe any diagnostic process at all
The most revealing technical question is some version of walk me through how you would diagnose this problem. A strong plumber describes a methodical process, isolating the cause before reaching for a fix, and naturally mentions code and safety. A weak one jumps straight to replacing a part. You do not need to be a master plumber yourself to hear the difference.
How to Score a Plumber Candidate
Scoring turns a set of interviews into a fair decision. Right after each interview, while it is fresh, rate the candidate 1 to 5 on each job-related competency, then compare totals across candidates rather than relying on who left the best impression.
Competency
What a 5 looks like
Technical skill and diagnostics
Diagnoses methodically; knows materials and methods
Code and safety awareness
Works to code; takes safety seriously; inspection-ready
Licensing and experience fit
License level and experience match the role
Customer service
Professional in a customer's home; explains clearly
Reliability and work ethic
Shows up, works hard, dependable for on-call
Coachability
Open to feedback; wants to improve and advance
Weight the competencies that matter most for the role, for example technical skill and code awareness for a lead plumber, or attitude and coachability for an apprentice. The point of the rubric is consistency: the same scale for every candidate, scored on job-related skills only, gives you a fair comparison and a documented basis for the decision.
Apprentice, Journeyman, and Master
Plumbing has three license levels, and knowing which one a role needs is half of hiring well. The level tells you what a plumber can legally do, how much supervision they need, and roughly where their pay sits. Match the level to the job rather than over- or under-hiring.
Level
What it means
Typical scope
Apprentice
In training under a licensed plumber
Works supervised; completing a multi-year apprenticeship
Journeyman
Passed the licensing exam; works independently
Handles most installs and repairs on their own
Master
Additional experience and exam
Can pull permits and supervise in many states; can run a business
Requirements and exact titles vary by state and locality, so confirm what your state requires and verify any candidate's license through your licensing board. Match the level to the role: a service call business may need journeymen, while a growing company adds apprentices to train up under them.
Licensing and Questions You Cannot Ask
This is the part free question lists skip, and it is the part that protects your business: verifying licensing, keeping every question about the job, and avoiding the salary-history trap. The rules are simple once you know them.
Verify the license, and ask for the level, not assumptions
Plumbing is a licensed trade in most states, and the license level tells you what a candidate can legally do and what supervision they need. Ask directly whether they are an apprentice, journeyman, or master plumber, and verify it rather than taking it on faith. An apprentice works under supervision and is still learning; a journeyman can work independently; a master can pull permits and supervise others in many states. Match the level to the role you are filling, and confirm the license is current and valid in your state. Requirements vary by state and locality, so check your own rules. This is general information, not legal advice.
Keep every question about the job, never a protected characteristic
The questions you must not ask matter as much as the ones you should. Federal law makes it illegal to base a hiring decision on a protected characteristic, so never ask about age or date of birth, about religion, about national origin, birthplace, or accent, about disability or health, about marital status, family, or pregnancy, or about race. In the trades these slip in as friendly small talk, which is the trap. Keep every question tied to plumbing skill, licensing, safety, reliability, and how the candidate would do the work. The kits on this page are written to stay on the right side of that line. This is general information, not legal advice.
Ask the same questions and score them the same way
A structured interview, where you ask every candidate the same job-related questions and score their answers on the same scale, is both fairer and more predictive than a free-form chat. It reduces the chance a decision rests on a gut feeling that could mask bias, and it gives you a documented, defensible basis for the hire. That is the point of the scoring rubric in this kit. For a small plumbing business, the structure also simply produces better hires, because it keeps the focus on the skills and reliability that predict success on the job. This is general information, not legal advice.
Plumbers are hourly and non-exempt; mind salary-history bans
Plumbing is manual, skilled trade work, which does not qualify for the white-collar exemptions, so plumbers are generally non-exempt and entitled to overtime at one and a half times their regular rate for hours over 40 in a week. Because the work often includes on-call, nights, and weekends, track hours carefully. One interview trap to avoid: a growing number of states and cities prohibit asking a candidate what they currently or previously earned. You can almost always ask about pay expectations for the role instead. When in doubt, ask what they are looking for, not what they made. This is general information, not legal advice.
Keep Every Question About the Job, Not the Person
Federal anti-discrimination law, enforced by the EEOC, makes it illegal to base a hiring decision on age, sex, pregnancy, race, color, religion, national origin, disability, or genetic information, so do not ask about them. Many states also ban asking about salary history, though you can ask about pay expectations. When a question is about the candidate's life rather than the job, leave it out. This page is a general reference, not legal advice.
Plumbers are paid hourly, with pay varying by license level, region, and whether the work is residential, commercial, or industrial. Set your range using government data as a baseline, then adjust for your local market and the candidate's level.
Median Near $63,000 a Year (BLS)
Plumbers, pipefitters, and steamfitters had a median annual wage of $62,970 as of the May 2024 data, with the lowest 10 percent below $40,670 (largely apprentices) and the highest 10 percent above $105,150 (U.S. Bureau of Labor Statistics). The trade is projected to grow about 4 percent through 2034, with roughly 44,000 openings a year.
Because demand is steady and many experienced plumbers are nearing retirement, a competitive, transparent pay range matched to license level helps a small business attract reliable plumbers. Benchmark to your local market, since pay runs notably higher in some metro areas and states.
Hiring for a Small Plumbing Business
A large contractor hires through a recruiting team with a defined process. A small plumbing business owner usually hires personally, with no HR support and high stakes, because a bad trade hire reaches customers fast. That combination is exactly why a structured kit and scorecard help. Here is how to approach it.
The owner is the hiring manager, the dispatcher, and often still on the truck
Most plumbing companies are small. The average plumbing business runs around five employees, which means the owner usually hires personally, between running calls and everything else. There is no recruiter and no HR department to build a fair, repeatable interview. That is exactly why a ready kit with set questions and a scorecard helps: it turns hiring from a rushed, gut-feel conversation into a structured process you can run consistently, even on a busy week, so you choose the right plumber instead of the one who happened to interview well.
A bad plumbing hire shows up in callbacks, code issues, and lost customers
In a trade, a weak hire is not an abstract cost. It shows up as callbacks, failed inspections, unhappy customers in their own homes, and safety risk on the job. Hiring on a good first impression alone is how that happens. The fix is to make every candidate show their actual diagnostic process and to score the answers the same way: the technical kit and rubric on this page are built to surface who can really do the work, not just talk about it, before a mistake reaches a customer's house.
The interview is only worth it if the new plumber actually sticks and ramps
Hiring the right plumber is step one; keeping them and getting them productive is where the value is realized. A signed offer, the first-week setup, safety and tool orientation, and a clear ramp turn a good hire into a dependable crew member. FirstHR fits this side of the process: document management to store the signed offer and the interview scorecards, an onboarding wizard and task workflows to build the new plumber's first-week and 30-60-90 plan, and employee profiles to place them on the team. To be clear on scope, FirstHR is an onboarding and HR platform, with applicant tracking coming soon, so it supports the steps after you choose your hire, and it does not run payroll or administer benefits.
From Interview to Onboarding
The interview is step one. A good plumber still needs a proper start to become a dependable part of the crew, so the value of choosing the right person is only realized if the onboarding that follows is just as structured. The signed offer, first-week setup, safety and tool orientation, and a clear plan are what turn a good interview into a productive hire.
Run a structured interview
Use the kit for the role, ask every candidate the same questions, and take notes in the space provided.
Score on the rubric
Rate each candidate 1 to 5 across the same competencies, then compare scores side by side, not gut feelings.
Make the offer
Once you pick your plumber, send the offer and capture acceptance, keeping the scorecards with the record.
Onboard and ramp
Set up the first week, safety and tool orientation, and a clear plan so the new hire ramps quickly.
Once you have chosen your plumber, the offer letter template sends the offer, and an onboarding template structures the first weeks. FirstHR connects that path: document management to store the signed offer and the interview scorecards, an onboarding wizard and task workflows to build the new plumber's first-week and ramp plan, and employee profiles to place them on the team. FirstHR is an onboarding and HR platform, with applicant tracking coming soon, so it supports the steps after you choose your hire, and it does not run payroll or administer benefits, so connect those separately.
Key Takeaways
Strong plumber interview questions make a candidate show real skill: how they diagnose a hidden leak, choose materials, and work to code.
Match the kit to the role: standard, technical, apprentice, behavioral and service, or phone screen.
Verify the license level (apprentice, journeyman, or master) and match it to the role; requirements vary by state.
Score every candidate 1 to 5 on the same rubric to compare fairly rather than on a gut feeling.
Never ask about a protected characteristic, and avoid salary-history questions where state law bans them.
A bad trade hire shows up as callbacks and unhappy customers; a structured interview and scorecard are cheap insurance.
Frequently Asked Questions
What questions should I ask a plumber in an interview?
Ask questions that make a candidate show real skill, not just describe it. Strong plumber interview questions cover a few areas: their training and license level, whether they lean residential or commercial, how they diagnose a problem they cannot see, how they choose pipe materials, their approach to code and safety, and how they handle customers in their homes. A practical test is to walk through a specific repair scenario, like a leaking water heater relief valve, and listen for a methodical process rather than a quick parts swap. For apprentices, focus on attitude and willingness to learn. The kits on this page give you ready-made question sets by role, so you can ask every candidate the same job-related questions and compare them fairly.
What technical questions should I ask a plumber?
Ask technical questions that reveal diagnostic thinking and code awareness, not just memorized facts. Good examples include how they locate a hidden leak behind a wall or under a slab, when they would use copper versus PEX versus PVC and why, how they clear a stubborn main drain and when they would choose hydro-jetting over a snake, and what they check to keep a job code-compliant and inspection-ready. A strong candidate gives a step-by-step process, uses correct terminology, and brings up safety and permits without being prompted. A weak one jumps straight to replacing parts. The technical kit on this page lists these questions alongside a note on what a strong answer sounds like, so even a non-plumber owner can evaluate the response.
How do I interview an apprentice or entry-level plumber?
Hire for attitude, reliability, and willingness to learn rather than experience. When interviewing an apprentice or helper, weight your questions toward why they want to become a plumber, how they have picked up hands-on skills before, how they take direction and feedback, and whether they are prepared for early starts and physically demanding days. Confirm practical basics like reliable transportation and willingness to enroll in an apprenticeship and study for licensing. You are assessing potential and work ethic, not a track record. A great entry-level candidate shows genuine motivation and coachability even without experience. The apprentice kit on this page is built around exactly these traits so you can assess raw potential consistently.
What is the difference between an apprentice, journeyman, and master plumber?
They are the three license levels in the plumbing trade, and they tell you what a plumber can legally do. An apprentice is in training and works under the supervision of a licensed plumber, typically while completing a multi-year apprenticeship that combines paid on-the-job hours with classroom instruction. A journeyman has completed that training, passed a licensing exam, and can work independently. A master plumber has additional experience and examination, and in many states can pull permits, run a plumbing business, and supervise journeymen and apprentices. Exact requirements and titles vary by state and locality. When hiring, match the level to the role, verify the license is current, and check your state's specific rules. This is general information, not legal advice.
What questions are illegal to ask a plumber in an interview?
Any question that touches a protected characteristic rather than the job. You cannot base a hiring decision on age, sex, pregnancy or family plans, marital status, religion, national origin or accent, race, color, disability, or genetic information, so you should not ask about them. In the trades these often slip in as casual small talk, which is the danger, so keep every question tied to plumbing skill, licensing, safety, reliability, and how the candidate would do the work. You also cannot ask about salary history in a growing number of states and cities, although you can ask about pay expectations for the role. When in doubt, ask whether the question is about the job or about the person. This is general information, not legal advice.
How do I verify a plumber's license?
Ask directly for the candidate's license level and number, then confirm it through your state or local licensing board, since most states regulate the plumbing trade. Do not simply take a stated license level on faith, because the level determines what work the person can legally perform and what supervision they require. Many state boards offer an online lookup to confirm a license is current and in good standing. Also confirm any local permit or registration requirements that apply in your area. Verifying licensing protects your business, your customers, and your inspections. Requirements and verification methods vary by state and locality, so check the specific rules where you operate. This is general information, not legal advice.
How should I score plumber candidates to compare them fairly?
Use a structured scorecard and apply it the same way to every candidate. Rate each person 1 to 5 on the same job-related competencies, such as technical skill, code and safety awareness, licensing fit, customer service, reliability, problem solving, coachability, and team fit, then compare the totals side by side. This is far more reliable and fairer than relying on a gut feeling about who interviewed best. A structured rubric also gives you a documented basis for the decision. The scoring rubric included in this kit does this for you, with evidence fields and an overall Advance, Hold, or Pass recommendation. Score only job-related skills, never anything tied to a protected characteristic. This is general information, not legal advice.
How much does a plumber make?
Plumber pay varies widely by experience, license level, region, and whether the work is residential, commercial, or industrial. The Bureau of Labor Statistics reports a median annual wage of 62,970 dollars for plumbers, pipefitters, and steamfitters as of the May 2024 data, with the lowest 10 percent earning below 40,670 dollars, reflecting early-career and apprentice workers, and the highest 10 percent earning above 105,150 dollars. Pay tends to run higher in high-cost metro areas and in states with strong demand. For a job posting or an offer, benchmark to your local market and the candidate's license level rather than the national median, and post a pay range where your state requires it. This is general information, not legal advice.
