Principal Mechanical Design Engineer - South Division

MWH Treatment; Hattersley; Hybrid; GBP 70,000 - 100,000; Full time

Job summary

MWH Treatment is seeking a Principal Mechanical Design Engineer to provide authoritative technical leadership across UK water and wastewater projects. You will own complex mechanical designs, ensure safety, sustainability and buildability, and mentor engineering teams.

Working with Discipline Leads and clients, you will drive design governance, support major bids, and deliver cost-efficient, high-quality mechanical solutions that meet programme and budget constraints.

Qualifications

• Degree-qualified mechanical engineer with UK water/wastewater sector experience.
• Strong leadership and governance skills across multidisciplinary teams.
• Ability to develop practical, safe and economical mechanical designs.

Responsibilities

• Lead and coordinate complex mechanical designs for water/wastewater projects.
• Provide technical leadership across multidisciplinary teams.
• Develop innovative, risk-balanced engineering solutions.
• Ensure designs are safe, compliant, buildable and cost-effective.
• Produce and review design calculations, specs, drawings and reports.
• Support major bids and project delivery strategies.
• Mentor engineers and uphold engineering governance.

Skills

Leadership

Mechanical design

Project management

Communication skills

Technical judgement

Education

Degree in Mechanical Engineering (BEng/MEng)

Chartered Engineer (CEng)

Job description

We are looking to strengthen our engineering team with a Principal Civil Design Engineer to join our Southern Division with flexible working available.

Engineer the Future of Water Infrastructur e

At MWH Treatment, we're looking for an experienced Principal Mechanical Design Engineer to provide technical leadership across some of the UK's most critical water and wastewater infrastructure projects.

This is a fantastic opportunity for a proven mechanical engineering professional to take ownership of complex design solutions, influence project delivery strategies, support major bids, and mentor engineering teams. You'll play a key role in delivering safe, innovative and commercially effective mechanical designs that support the UK's essential water infrastructure.

As a recognised technical authority, you'll lead the development and assurance of mechanical engineering designs while driving quality, sustainability and engineering excellence across the business.

The Role

As a Principal Mechanical Design Engineer, you will provide authoritative technical leadership across a range of water and wastewater projects, ensuring designs are safe, compliant, buildable and cost effective.

Working closely with Discipline Leads, Chief Engineers, Project Managers, construction teams, clients and suppliers, you will transform complex engineering challenges into practical, high-quality solutions while maintaining the highest standards of technical governance and quality assurance.

Key responsibilities will include:

• Lead and coordinate the delivery of complex mechanical engineering designs within the water and wastewater sector.
• Provide technical leadership and guidance across multidisciplinary engineering teams.
• Develop innovative, practical and risk-balanced engineering solutions.
• Ensure all designs are safe, sustainable, compliant, buildable and commercially effective.
• Produce, review and approve mechanical design calculations, specifications, reports, drawings and technical documentation.
• Support major project bids and contribute to successful project delivery strategies.
• Act as a technical reviewer and maintain high standards of engineering governance and quality assurance.
• Manage technical delivery from broad project briefs, balancing programme, cost, quality and resource requirements.
• Identify and manage technical risks, ensuring issues are escalated and resolved effectively.
• Liaise with clients, contractors, suppliers and key stakeholders to deliver successful project outcomes.
• Support and mentor engineers, helping to strengthen technical capability across the business.
• Promote a culture of continuous improvement, innovation, safety and customer focus.

You’ll be an experienced Mechanical Design Engineer with strong leadership capabilities and a proven track record of delivering complex engineering solutions within the water industry.EssentialDegree qualified in Mechanical Engineering (BEng, MEng or equivalent).Significant experience delivering mechanical engineering designs within the UK water and wastewater sector.Strong understanding of water and sewage treatment processes and associated mechanical systems.Experience leading multidisciplinary engineering design projects.Knowledge of pumping systems, pipework design, valves, treatment process equipment, sludge handling systems and associated mechanical infrastructure.Ability to develop practical, efficient and economical engineering designs and plant layouts.Good understanding of related engineering disciplines including civil, electrical, process engineering and project management.Strong technical judgement and problem-solving abilities.Excellent communication skills with the ability to present technical proposals clearly, confidently and convincingly.Proven ability to manage competing priorities and deliver quality outcomes to programme.Commitment to health and safety, quality and engineering excellence.DesirableChartered Engineer (CEng) status.Experience acting as a technical reviewer, approver or signatory.Experience managing, mentoring or developing engineering teams.Strong understanding of relevant industry standards, specifications and regulations.Established professional network within the UK water sector.Experience delivering designs for treatment works, pumping stations and associated infrastructure projects.

Why Join MWH Treatment?

Work on nationally significant water and wastewater infrastructure projects.Influence key technical decisions across major programmes of work.Lead and develop talented engineering teams.Collaborate with highly experienced multidisciplinary professionals.Be part of a business committed to innovation, sustainability, safety and engineering excellence.Enjoy excellent opportunities for professional development and career progression.

Join Us

If you're an experienced Mechanical Design Engineer looking to step into a senior technical leadership role where you can drive innovation, influence project success and help shape the future of water infrastructure, we'd love to hear from you.

Join MWH Treatment and play a leading role in delivering the vital infrastructure that supports communities and protects the environment across the UK.