Principal Mechanical Design Engineer - Water Industry

Lead mechanical design for national water programmes Purpose And Scope Of The Role

Tetra Tech’s Water Consultancy is seeking multiple Principal Mechanical Design Engineers to lead mechanical design delivery across major, long‑term UK water industry frameworks. You will own mechanical design outputs for pumping systems, aeration and process plant equipment from optioneering through detailed design and construction support, producing specifications, P&IDs, schedules, calculations and procurement documentation. Projects include a £100 million, 10‑year United Utilities framework and a broad AMP8/AMP9 portfolio.

You will coordinate multi‑disciplinary teams of engineers, modellers and data analysts, engage clients and supply‑chain partners, and provide technical assurance on multi‑million‑pound capital schemes.

In the short term you will deliver robust mechanical designs and site survey outputs. Over the medium term you will optimise plant performance, improve constructability and reduce whole‑life carbon and cost across programmes. Longer term you will capture technical knowledge, develop technical leaders and influence regional delivery strategy, with clear progression into senior technical or programme leadership roles.

• Pumping and process systems design – Demonstrable experience sizing and specifying pumps, aeration systems and ancillaries with justified selection and performance calculations.
• Multidisciplinary coordination – Proven ability to integrate mechanical designs with civil, structural, electrical, process and ICA disciplines and lead technical workshops and HAZOPs.
• Technical documentation and digital skills – Proficiency producing P&IDs, GA drawings, datasheets and use of AutoCAD/3D tools or similar digital design workflows.
• Regulatory, safety and constructability awareness – Strong knowledge of CDM duties, statutory standards and designing for safe, maintainable installations.
• Commercial and client engagement – Track record managing design deliverables to time, cost and quality, advising clients and supporting procurement on NEC/ECC or similar contracts.

Expected: IMechE‑accredited degree or equivalent, chartered or working towards chartership, substantial water sector experience. Desirable: postgraduate qualification and demonstrable AMP programme experience.

Hybrid working with regional office attendance; typical expectation two to three days per week onsite depending on project needs. Travel to client sites and project locations across the UK will be required. Competitive salary and benefits; flexible arrangements considered in line with delivery requirements.

In alignment with the Equality Act 2010, we will make reasonable adjustments to support candidates and employees requiring additional arrangements. This could include adaptations to work schedules, training approaches, or the physical workspace. Please inform us if you need any accommodations during the recruitment process or in your day-to‑day role.