Plumbing Engineer Interview Questions: What to Ask New Hire

What is a plumbing engineer job description?

A career as a plumbing engineer overlaps several key industries, including civil engineering, mechanical engineering, and fire protection engineering, according to information from the National Institute of Building Sciences.

A plumbing engineer designs plumbing systems for private, public, or commercial buildings, and may be involved in designing systems for potable water, sewer waste, stormwater drainage, and fire suppression, according to ZipRecruiter’s job description. Typically, plumbing engineers use software, such as AutoCad or Revit, in the mechanical, electrical, and plumbing (MEP) fields.

Job search templates, guidelines, and job postings list requirements for a plumbing engineer as: A bachelor's degree in an engineering field, professional engineering licensure, a minimum of five years of experience, and plumbing design certification.

General interview questions

1. Why do you want to work in plumbing design?

2. Why do you want to work for our company?

3. What are your career goals?

4. Can you give us a list of references?

General plumbing engineer job interview questions allow employers to discover applicants' backgrounds, including their goals, what drives them, and how they approach challenges. Companies should formulate a hiring process to narrow the best candidates for the position.

At McWilliams & Son in Texas, a company that generated $12 million in annual sales in 2020, managers follow a layered hiring process to ensure new hires get placed in the right role.

“Interviews are always going to be with two different teams,” relates CFO Brad Pesek, who shared tips on a recent episode of ServiceTitan's “Toolbox for the Trades” podcast. “If they do well with the first team, they are passed on to a second round. Four people will have had a ‘touch’ on them before we consider hiring them.”

1. Why do you want to work in plumbing design?

The classic "Tell me about yourself" question remains relevant, because hiring managers need to know why an engineer candidate chose this field. It allows candidates to share why they have a passion for their work and how they want to continue their knowledge in the field. The best candidates communicate clearly and exhibit positive traits like integrity, dependability, and problem solving.

2. Why do you want to work for our company?

This allows applicants to demonstrate their knowledge of your company and its core values. Find out what applicants know about the position, and what type of work they expect to perform.

Are they looking for a better work-life balance? Do they want to work remotely? What are their work schedule expectations? Asking these questions puts their expectations, and yours, on the table for everyone to see.

This is also the time to ask about their qualifications, certifications, and work history, including how long they worked at previous jobs. You may also want to ask whether their current employer knows they're looking for a new job.

3. What are your career goals?

Do they simply want to earn more money, or are they interested in exploring a long-term career path? Either type of plumbing engineer candidate may be a perfect fit for your company. Knowing what drives an employee and what they aim to accomplish shows their motivation and long-range planning. It can also help you determine if your company can provide opportunities to meet their career goals, which may result in a long-term employee.

4. Can you give us a list of references?

Hiring managers need to hear from others how applicants performed at previous jobs, including information about their personality, interactions with co-workers, and how they tackled challenging design projects.

Behavioral interview questions

1. How do you work with other team members (or clients) to provide the best design?

2. How do you deal with difficult co-workers?

3. How do you prevent mistakes on your projects?

4. Here's a plumbing engineering scenario. How would you handle this?

The key to behavioral interview questions? Discovering the attitudes of your applicants to gain insight into how they approach problems and interact with others.

“We hire for attitude before we hire for aptitude,” says Angie Snow, Vice President of Western Heating & Air in Utah, who always asks one question to ascertain attitudes of candidates: “How’s your day going so far?”

She calls a simple question like that "experiential queries" to see how candidates answer questions. Their values, whether positive or negative, shine through in their answers and the way they answer, says Snow, who also serves as Director of Customer & Product Training at ServiceTitan, and Success Coach at GoTime Success Group and Snow Business Coaching.

1. How do you work with other team members (or clients) to provide the best design?

Gain understanding into how applicants approach teamwork, and how they communicate with co-workers, other professionals on the project, and clients. New construction presents many challenges, and good plumbing design is essential to the safety and efficiency of structures. Understanding building requirements and achieving solutions to problems requires knowledge, problem-solving skills, excellent communication, and teamwork.

2. How do you deal with difficult co-workers?

Resolving disagreements is a part of teamwork, so it's a good idea to ask about their strategy in resolving differences, especially if they oversee employees. If the role is managerial, they need to show an ability to facilitate solutions in the midst of differing opinions, and possess an effective management style. Your company's service to clients and the integrity of projects should be of utmost importance to everyone on the team.

3. How do you prevent mistakes on your projects?

Plumbing engineers need to be organized and detail-oriented. Finding out what checks and balances they use to detect mistakes, and how they remedy them, can show if they have a strong accountability process and how thoroughly they complete their work. 

4. Here's a plumbing engineering scenario. How would you handle this?

Giving applicants an unknown job scenario that requires a specific skill set gives them the opportunity to demonstrate quick thinking and intuitive problem-solving skills. Their answers will indicate their thought processes and breadth of knowledge.

Technical knowledge interview questions

1. How do you design sustainable systems?

2. What was your most challenging project, and what did you learn from it?

3. How do you approach design for a challenging layout?

Asking technical questions, such as preferred design software and why, measure an applicant's ability and knowledge. Plumbing questions about types of pipe fittings, materials like PEX tubing or PVC pipes, hot water heaters, and plumbing fixtures like faucets, get into the details. Those who design complex water, drainage, and fire protection systems must know how to take the right precautions to ensure safety and efficiency.

1. How do you design sustainable systems?

In this eco-conscious era, clients want increased efficiency and reduced energy use. Designing sustainable systems, whether through low-flow fixtures or the use of greywater systems, remains key. Assess candidates' knowledge on sustainability to deliver results that satisfy your customers.

2. What was your most challenging project, and what did you learn from it?

The answers to these questions provide insight into a candidate's knowledge, strengths, and ability to grow. Employees who can quickly learn and adapt to new challenges strengthen projects and, in turn, your company.

3. How do you approach design for a challenging layout?

Finding out how candidates approach challenges is key. The process used to uncover solutions to uncommon design challenges shows their level of critical thinking, which often dictates whether a project succeeds.

Technology interview questions

1. Are you familiar with job costing software?

2. What is your experience with using mobile technology in the industry?

3. How does construction software provide a better client experience?

Ask technology-related questions to see how much the candidate knows about industry trends and cloud-based software, such as ServiceTitan Plumbing Software, to streamline plumbing construction projects. Real-time project data and increased communication between stakeholders ensure projects get completed on time and on budget. 

1. Are you familiar with job costing software?

If your company uses job costing software, asking this question gauges their familiarity with the process. The software allows project managers to track actual vs. budgeted costs at every stage of the project, from processing expenses and purchase orders, to tracking labor hours through mobile timesheets.

2. What is your experience with using mobile technology in the industry?

Mobile technology allows those involved in the project to see real-time schedules and other critical job information. ServiceTitan Mobile streamlines communication from the field to the office, so nothing gets overlooked.

3. How does construction software provide a better client experience?

If the applicant has experience with construction software, they should be able to share how it enhanced coordination and communication between project participants. Construction software allows managers to coordinate with HVAC and other areas, and communicate progress to customers. 

Payroll interview questions

1. What are your salary expectations?

2. What do you expect in terms of bonuses?

Online job postings show a current demand for plumbing engineers or plumbing design engineers, from roughly 6,000 to 10,000 job openings nationwide, depending on job search website or job title. Nationally, jobs in the plumbing occupation are forecasted to rise by 20,900 jobs within a 10-year period ending in 2029, according to the U.S. Bureau of Labor Statistics. Offering a competitive salary puts your company at the forefront for top talent.

1. What are your salary expectations?

Offer competitive rates for plumbing engineers, based on the particular skill set and geographic area. In general, plumbing engineer salaries range from $38,500 to $121,000 annually, with a median of $80,566, according to ZipRecruiter. Business owners should also offer appealing benefits to attract the best job candidates and reduce turnover rates.

2. What do you expect in terms of bonuses?

Asking about bonuses or other incentives upfront allows you to share how your company values employee performance. These and other questions enable you to identify the best candidates and make the best hires for your company.