Principal Mechanical Engineer - Water

The Opportunity

The South of England is at the heart of one of the UK's largest periods of investment in water infrastructure. Through AMP8, water companies are investing in resilient, sustainable assets that will improve environmental performance, strengthen water security and support growing communities. At Stantec, we’re helping deliver these nationally significant programmes and are looking for a Principal Mechanical Engineer to join our growing team in Brighton, London, High Wycombe, Reading or Southampton.

As part of one of the UK's leading multidisciplinary water consultancies, you'll work alongside recognised technical specialists on a diverse portfolio of water and wastewater treatment works, pumping stations, conveyance systems and complex mechanical engineering projects. With a strong pipeline of work, investment in digital engineering and a collaborative culture, you'll have the opportunity to develop your career while helping shape the future of water infrastructure across the South of England.

As a Principal Mechanical Engineer, you will lead the technical delivery of mechanical engineering projects across the full project lifecycle, from feasibility and optioneering through to detailed design, construction support and commissioning. You'll collaborate closely with multidisciplinary teams, clients and contractors to develop practical, sustainable engineering solutions that deliver successful project outcomes.

You'll provide technical leadership across water and wastewater treatment facilities, pumping stations and mechanical process systems, ensuring designs meet the highest standards of quality, safety and sustainability. Alongside project delivery, you'll mentor engineers within the team, contribute to technical governance, support project planning and work with clients to deliver innovative engineering solutions.

Your expertise will help deliver vital infrastructure that improves water resilience, protects the environment and supports communities across the South of England. Through innovative mechanical engineering solutions, you'll contribute to projects that enhance operational performance, improve treatment processes and provide long-term value for our clients.

You'll also play an important role in developing future engineering talent by mentoring colleagues, sharing technical knowledge and strengthening capability across the business. Your contribution will reinforce client relationships, support successful project delivery and maintain Stantec’s reputation for technical excellence throughout AMP8 and beyond.

• Degree qualified (or equivalent) in Mechanical Engineering.
• Chartered or Incorporated Engineer (CEng/IEng) or actively working towards
• Experience delivering detailed mechanical design within the UK water sector.
• Strong understanding of water and wastewater treatment infrastructure, pumping stations and associated mechanical systems.
• Experience leading technical project delivery and coordinating multidisciplinary teams.
• Excellent communication and stakeholder management skills.
• Experience mentoring and supporting the development of junior engineers.

• Experience working alongside delivery contractors.
• Experience across both infrastructure and non-infrastructure projects.
• Experience supporting bids or business development activities.

We put people first: We're proud of our friendly, inclusive and collaborative environment where everyone feels valued and driven to succeed.

We are driven to achieve: Named in the top 50 companies to work by Glassdoor 2025. Recognised by Corporate Knights as one of the world's top 10 most sustainable companies 2025. Named ‘Best Place to Work’ and ‘International Consulting Firm of the Year’ at the NCE Awards 2024.

We do what is right: Industry leading training and development as well as paid for professional subscriptions. A professional progression plan, supporting you to become chartered with ICE.

We are better together: A supportive and collaborative team environment and Early Careers peer group and wider ERG network (see more on our ERGs here: Stantec Employee Resource Groups).

Growth: We're on an…