Senior Mechanical Engineer

Senior Mechanical Engineer – Wastewater Non‑Infrastructure Projects
Step into a role where your engineering expertise directly protects the environment, strengthens local communities, and shapes the future of wastewater treatment across the Thames Valley.

As a Senior Mechanical Engineer within our Thames Valley Delivery Office, you’ll play a leading role in modernising our wastewater treatment plants — from early design thinking through to construction and commissioning. You’ll work closely with a wide range of specialists, champion safe and sustainable design, and bring forward innovative solutions that improve life for millions of people.

This is an opportunity to apply your technical strengths while influencing real change across a major utility — in a team that values collaboration, diverse perspectives and continuous professional growth.

What you’ll be doing

• Leading mechanical design development across multiple wastewater treatment projects — from concept and feasibility through to contract award.
• Shaping clear and robust project briefs from a mechanical engineering standpoint.
• Identifying risks and opportunities to support accurate pricing and scope definition.
• Reviewing surveys, drawings and contractor proposals before construction begins.
• Providing design assurance throughout detailed design and construction phases.
• Supporting project teams during commissioning and asset handover.
• Carrying out design reviews to ensure safe, resilient and future‑focused solutions.
• Acting as the key contact for CDM Designer or Principal Designer responsibilities.
• Contributing to the ongoing improvement of our Technical Asset Standards.
• Demonstrating our zero‑compromise approach to health, safety and wellbeing.

We’re looking for someone who:

• Has experience developing technical solutions and project briefs within mechanical engineering.
• Holds an HNC/HND in Mechanical Engineering, a degree, or a Master’s degree.
• Understands industrial processes relevant to mechanical engineering.
• Is a chartered engineer or working towards chartership (other professional progression also considered).
• Has experience in wastewater treatment projects or similar highly regulated environments.
• Can engage confidently with different stakeholders — from on‑site teams to external partners.
• Is comfortable managing multiple projects and prioritising effectively.
• Understands the principles of project delivery in process industries.
• Has knowledge of health and safety requirements, including CDM Regulations 2015.

What’s in it for you?

You’ll be at the heart of how we deliver essential infrastructure — working alongside talented colleagues, contractors and specialists. We’ll support your technical development, professional progression and personal wellbeing, while empowering you to make a meaningful impact for our customers, our environment and future generations.

This is a role where your voice is valued, your expertise is respected, and your work truly matters.

• Competitive salary from £55,000 to £65,000 per annum.
• Annual Leave -26 days holiday per year, increasing to 30 with the length of service. (plus bank holidays)
• Access to many benefits to help you take care of your health 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.
• Performance-related pay plan directly linked to company performance measures and targets.
• Generous Pension Scheme through AON.

Find out more about our benefits and perks (Please note different T&Cs apply if on secondment)

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.