Top 25 Plumbing Interview Questions and Answers in 2024

Editorial Team

Plumbing Interview Questions

A plumber primarily installs, maintains, and repairs pipes and fixtures used for cooling, heating, water distribution, and sanitation system in commercial and residential homes. This job requires someone who has relevant experience in plumbing and possesses the skills needed to perform all the plumbing tasks. If you have an upcoming plumbing interview, here are questions you can expect and the best response to each of them.

1. Why Are You Interested in This Role?

I have been keenly following your company on social media. It is one of the leading in the industry. I also like the way you treat your employees and the support you give them while executing their work. For these reasons, I have always desired to be a part of your workforce. Given a chance, I will use my expertise to ensure plumbing issues are addressed on time.

2. What are The Roles of a Plumber?

A plumber analyzes the design and specifications of a building then maps up the layout for the drainage system, pipes, and other plumbing materials. He/she also installs pipes and fixes, i.e., sinks, toilet, gas, steam, air, water, and other liquids. Additionally, the plumber installs equipment, support for the pipes and fixtures prior to installation. After that, team up with electricians, general contractors, and other construction professionals in installing the drainage system, bathrooms, etc.

3. What Are the Qualities That a Plumber Should Poses to Be Effective?

An excellent plumber should have good problem-solving skills to analyze a situation, develop ideas quickly, and select the best course of action. He/she should have impressive communication skills to effectively communicate with a client and make them understand the problem and the equipment they need to solve the issue. Moreover, the plumber should be dedicated to his work and ensure proper time management to execute his work effectively.

4. What Major Challenges Did You Face During Your Last Role? How Did You Handle It?

The major challenge was the lack of cooperation from team members and customers. Most of my team members could argue on a task, and everyone wanted to apply their ideas. They wasted a lot of time trying to agree on the tools to use and install the fixtures. Some members were also reluctant to take up their duties, which made me work extra time to finish on the areas they had neglected.

5. Describe Your Daily Routine as a Plumber

I install and repair pipes that supply gas and water as well as dispose of waste away from businesses and homes. I fix plumbing fixtures such as sinks, bathtubs, toilets, and appliances like washing machines and dishwashers. Additionally, I train apprentices and supervise junior plumbers as well as diagnose and solve plumbing issues.

6. What Is the Biggest Challenge You Foresee in This Job?

The biggest challenge is working with a team that doesn’t collaborate. When people don’t cooperate, work becomes harder. Some customers may be rude and don’t understand the plumbing work. It becomes a challenge to explain to them the materials you need and the significance of those materials. However, I will use my experience to make my team work together and resolve issues before they escalate.

7. Briefly Explain Your Plumbing Experience

I have worked for over 15 years as a plumber. Over this period, I have worked with five companies. I have the skills to handle manual dexterity and physical damage, i.e., cleaning sewer lines, installing appliances such as water heaters, refrigerators, dishwashers, and water softeners. I am conversant with all the plumbing technology and possess general business and administration skills. Additionally, I comply with all the regulatory rules in plumbing.

8. How Do You Stay Motivated at Work?

My biggest motivation is when I manage to solve a plumbing issue and achieve the best results. I also get motivated when a customer recognizes, appreciates, and feels happy about my work. The appreciation makes me work harder and ensure the quality of my work is amazing. Additionally, I enjoy training junior plumbers, and I get motivated when I see them trying their best in the plumbing field.

9. Describe a Time You Failed in This Role and The Lessons You Learned

On one occasion, I assigned the newly hired plumbers some tasks and never supervised them. So, they ended up fixing pipes wrongly. I had to remove every pipe they had fixed and do it afresh. I learned to always work with inexperienced workers and help them learn. That way, mistakes that can be avoided will not occur.

10. List the Major Tools Required for Plumbing

The major tools that a plumber needs to execute his work effectively include:

  • Closet auger
  • Tubing cutter
  • Sink auger
  • Flange plunger
  • Teflon tape
  • Adjustable wipe wrench
  • Faucet packing and washers
  • Faucet valve reseating tool
  • Faucet valve seat wrench

These tools are very significant for fitting work, carrying out repairs, or fixing a tap. A plumber must handle these tools carefully to avoid damage.

11. How Do You Unclog a Blocked Sink?

A sink may block due to grease, hair, soap residues, or when other debris is caught up in your draining pipe. My first remedy would be pouring hot water into it. Hot water helps to melt any soap, fat, or greasy substances. In the case where the sink doesn’t unclog after using hot water, I would use a special wire and insert it into the sink drainage pipe to soften any solid substance inside the pipes. Then pour hot water once again.

12. What are The Different Types of Chemical Drain Plumbers Use?

Plumbers use oxidizing drain cleaners, which consist of household bleach, nitrates, and peroxides. The chemicals stimulate the organic material of the clog material to lose an electron and oxidizes it. The oxidizing drain chemicals additionally produce gas and heat, which clears the blockage. They also use acid drain cleaners, consisting of a higher concentration of hydronium ions and acids that reacts with the substance causing the clog and generates heat. The heat dissolves the substances and gets rid of the blockage.

13. What is an Angle Stop?

An angle stop is a shutoff valve in between a water supply pipe and the fixtures it supplies. Plumbers use it to shut off water to a fixture when a failure, repair, or leakage occurs.

14. Mention the Health and Safety Challenges a Plumber Faces

A plumber mainly gets exposed to flammable and combustible material. He/she works in risky areas that can cause musculoskeletal injuries. Their eyes are usually at risk from flying particles. Additionally, a plumber is at high risk of electric shock when working on pipes that are surrounded by electrical wires. Hot equipment such as water heaters and steam lines also poses a threat to plumbers.

15. What Causes Sump Pump Failure?

Plumbers primarily use a sump pump to get rid of water that accumulates during floods. However, the sump may stop functioning due to a switch problem or excess debris accumulating and interfering with the switching. Additionally, the pump may shift position and get in the basin and distort the switching mechanism.

16. How Do You Fix a Leaky PVC Water Pipe?

If a PVC water pipe is leaking, I will drain the water from the pipe and make sure the leakage pipe is dry, and cut the affected part. Then, I will ensure the halfpipe has a stop inside. Next, I will use an adhesive to rub the inside of the patch and ensure its length is enough to connect firmly with the leaking pipe. Lastly, I will put the patch on the pipe and slide it into the leaking pipe and keep it overnight for it to dry.

17. What is an Eductor?

An eductor refers to a device that uses a nozzle and throat fixed in a stream of water to create a partial vacuum that draws air or liquid into a stream. Plumbers use an eductor to draw regeneration chemicals into an ion exchange water treatment systems such as a water softener or deionizer.

18. Can a Clogged Vent Stop Drainage?

A toilet that lacks a vent will not flush out waste from its bowl. However, any other drains can work appropriately even without a vent.

19. Highlight the Home Remedies to Clear Clogged Drains

To clear a clogged drain, you need to take a cup full of baking soda and pour it into the drain. After that, pour half a cup of vinegar and flush after 15 minutes with hot water. You can also add equal amounts of vinegar, salt, and baking soda to the drain. Then pour hot water into it after one hour. Additionally, you can sprinkle half a cup of salt, and the same amounts of baking soda, then flush it with hot water.

20. What Precautions Should a Plumber Take for Health and Safety Purposes?

A plumber should put on suitable gloves and footwear while handling metal pipes or sewage plants and ensure the tools and equipment are in a good state to avoid accidents and damage. He/she should also ensure the working area is clear. To avoid electric shocks, plumbers should ensure to switch off the electricity when working on areas where water and electricity have come into contact.

21. How Can a Person Avoid Bathroom Clog?

You can prevent bathroom blockages by flashing out the drainage regularly with hot water. You can also apply a pipe shield to drain lines once every month to prevent soap scums from accumulating and causing clogs. Additionally, one can take a cup of vinegar, place it in a plastic bag and leave it in the showerhead overnight to eliminate mineral deposits in it.

22. How Do You Work on a Leaking Bathtub Drain Right at The Drain Hole?

A leaking bathtub drain can be caused by hairs in the drain hole. I would use pliers and stick the handle-end down the drain, then catch the nibs or hairs and unscrew. Next, I will wash off the old plumber’s putty and slide new washers in between the shoe and the underside of the tub. Lastly, I will put puffy around the chrome flange and screw it back in place.

23. How Do I Get a Snake from a Tub Drain

First of all, it is not possible for a snake to go through the drain hole at the end of the tub. However, if it happens, I will take off the overflow plate, which is the chrome thing on the tub wall having two screws, and then pull it out.

24. What Causes the Toilet to Bubble or Shower to Overflow When I Run the CWM?

There is a possibility that your washing machine is connected too close to the suds rinse zone. Thus, the washer waste ties into the soil line. What happens is the water rushes to the suds at a greater speed, pushing the head of the suds.

The suds then come up into the fixture or a toilet since the fixture is the nearest place of relief. To solve this problem, a plumber should connect the washing machine, shower, kitchen sink, or dishwasher at least 5 inches downstream from any fixture branch.

25. How Do You Seal the W/c Tank to The Bowl?

I would use a large donut gasket – the type that is square inside, to match the shape of the nut on the end of the tank. Then, I would tighten the bolts down uniformly until the tank is snug on the bowl. I ensure it is not overtight to prevent the tank or bowl from breaking.


To ace your next plumbing interview, study and practice these questions. Knowing the kind of questions to expect will give you the much-needed confidence in an interview. Also, remember to put on attire that fits an interview. Be audible when answering every question. Additionally, be sure to arrive on time to avoid becoming questionable about time management. Try to arrive at least 30 minutes before the time of the interview. That way, you will avoid the last-minute rush, which is not appropriate with an interview.