Principal Mechanical Engineer

idibu; England; Hybrid; GBP 65,000 - 80,000; Full time

Job summary

A leading water management company in the UK is looking for a Principal Mechanical Design Engineer to innovate and lead in water infrastructure. The role requires expertise in mechanical engineering and includes responsibilities like setting project requirements and leading design initiatives. Successful candidates will receive a competitive salary of £65,000 to £80,000, along with various benefits, including a car allowance.

Benefits

26 days holiday per year, increasing with service

Annual bonus

Private medical healthcare

Car allowance of £5,800

Cycle-to-Work schemes

Qualifications

• Degree qualified in mechanical engineering with charter.
• Background in water and wastewater treatment essential.
• Experience in lead design engineering roles.

Responsibilities

• Set technical requirements for strong project foundations.
• Lead innovative designs for water sectors.
• Achieve technical sign-off for project handover.

Skills

Mechanical Engineering expertise

Knowledge of sludge digestion

Experience with biogas and CHP systems

Understanding of regulatory requirements

Education

Degree in Mechanical Engineering

Job description

Lead the Future of Water Engineering – Become Our Principal Mechanical Design Engineer

Are you ready to shape the future of water and wastewater infrastructure? As our Principal Mechanical Design Engineer, you’ll take the lead in driving innovation, setting engineering standards, and mentoring a talented team of professionals. This is more than a technical role — it’s a strategic opportunity to become the ‘Intelligent Client’ at the heart of our AMP8 ambitions and beyond.

Your expertise will be pivotal in delivering sustainable, high-performing assets that make a real difference to communities and the environment.

What you’ll be doing as a Principal Mechanical Design Engineer

• Set precise technical requirements with Project Definition Briefs for strong project foundations.
• Refine Technical Asset Standards to enhance process efficiency and effectiveness.
• Uphold engineering standards in Mechanical Engineering to optimise asset performance.
• Lead the development of innovative designs for the water and wastewater sectors.
• Inspire teams on mechanically focused projects, driving meaningful change.
• Achieve technical sign‑off and assurance for seamless project handover.
• Support the advancement of innovative technologies through research.

Location: Hybrid – Clearwater Court, Reading (Office or site based 3‑4 days a week)

Working Pattern: 36 hours a week. This position requires the candidate to have access to a vehicle and a valid driver's licence. Additionally, there is a car allowance of £5,800 included.

What you should bring to the role

To thrive in this role, the essential criteria you’ll need are:

• Be degree qualified or equivalent in mechanical engineering with a charter through a relevant awarding body.
• A Mechanical Engineering background in one or more sludge digestion and treatment, biogas and CHP systems, water and wastewater treatment, pumps/piping systems, or process equipment is essential.
• Understand the regulatory environment to comply with our engineering regulatory requirements.
• Had exposure to lead design engineering roles.

Additional skills and experiences would be excellent to have/bring

• Previous experience in the water industry.

What’s in it for you?

• Offering between £65,000 to £80,000 per annum, depending on the skills and experience of the successful candidate, plus a £5,800 car allowance.
• 26 days holiday per year, increasing to 30 with the length of service (plus bank holidays).
• Car allowance.
• Annual bonus.
• Performance‑related pay plan directly linked to company performance measures and targets.
• Private medical health care.
• Access to a range of benefits to help you take care of you and your family’s health and well‑being, and your finances – from annual health MOTs and access to physiotherapy and counselling to Cycle‑to‑Work schemes, shopping vouchers and life assurance.

Find out more about our benefits and perks.

Who are we?

We’re the UK’s largest water and wastewater company, with more than 16 million customers relying on us every day to supply water for their taps and toilets. We want to build a better future for all, helping our customers, communities, people, and the planet to thrive. It’s a big job and we’ve got a long way to go, so we need help from passionate and skilled people, committed to making a difference and getting us to where we want to be in the years and decades to come.

Learn more about our purpose and values.

Working at Thames Water

Thames Water is a unique, rewarding, and diverse place to work, where every day you can make a difference, yet no day is the same. As part of our family, you’ll enjoy meaningful career opportunities, flexible working arrangements and excellent benefits. If you’re looking for a sustainable and successful career where you can make a daily difference to millions of people’s lives while helping to protect the world of water for future generations, we’ll be here to support you every step of the way. Together, we can build a better future for our customers, our region, and our planet. Real purpose, real support, real opportunities. Come and join the Thames Water family. Why choose us? Learn more.

We’re committed to being a great, diverse, and inclusive place to work. We welcome applications from everyone and want to ensure you feel supported throughout the recruitment process. If you need any adjustments, whether that’s extra time, accessible formats, or anything else, just let us know, we’re here to help and support. When a crisis happens, we all rally around to support our customers. As part of Team Thames, you’ll have the opportunity to sign up to support our customers on the frontline as an ambassador. Full training will be given for what is undoubtedly an incredibly rewarding experience. It’s also a great opportunity to learn more about our business and meet colleagues.

Disclaimer

Due to the high volume of applications we receive, we may close the advert earlier than the advertised date, so we encourage you to apply as soon as possible to avoid disappointment.