Principal Mechanical Engineer – WaterLeading Engineering Consultancy | Water Sector | Hybrid Working | Long-term Contract | Outside IR35 | Competitive RateThe Opportunity

We''re recruiting a Principal Mechanical Engineer to deliver high-quality mechanical engineering design and technical leadership across multiple water sector projects. You''ll be responsible for leading mechanical engineering workstreams, ensuring compliance with sector standards, managing design delivery, and mentoring engineering teams.

Contract Details: Outside IR35 | Competitive daily/monthly rate | Hybrid working| Long-term contract

MUST HAVE: Current water sector experience. This is a senior technical role for an SQEP (Suitably Qualified Experienced Person) mechanical engineer with proven, recent expertise in water, wastewater or biosolids treatment. You''ll have the capability to lead mechanical engineering on projects or groups of projects, managing design quality, timescales, cost and compliance. You''ll work collaboratively across disciplines, liaising with clients and partners to ensure integrated delivery.

Mechanical Engineering Design & Delivery

• Lead mechanical engineering workstreams on water sector projects
• Produce and approve mechanical design deliverables including:
  • Process Flow Diagrams and Plant Layouts
  • Equipment Specifications and Datasheets
  • Pumping system calculations
  • Material requisitions and procurement specifications
• Ensure designs are safe, practical, cost-effective and compliant with UK and international standards
• Manage design timescales, budgets and resource allocation
• Carry out Lead Mechanical Engineer roles on assigned projects or project groups

Technical Compliance & Quality

• Ensure full compliance with Company and Client policies, codes and standards
• Maintain rigorous Quality Assurance processes and auditable technical records
• Prepare and manage technical files in accordance with CDM requirements
• Conduct design reviews and approve design deliverables
• Ensure all work meets water sector regulatory and client specifications

Stakeholder & Partner Coordination

• Liaise effectively with other engineering disciplines (civil, electrical, process, etc.)
• Engage with clients and external partners to ensure integrated design delivery
• Communicate design decisions and progress to project management
• Manage supplier relationships and technical bid assessments
• Support value engineering and cost optimisation discussions

Specialist Mechanical Engineering

• Deliver mechanical engineering across multiple water treatment applications
• Provide expert input on pumping systems, chemical storage, asset condition
• Support feasibility studies and option appraisals
• Contribute technical knowledge to bid preparation and early contractor involvement projects

Essential Qualifications & Experience

• MUST HAVE: Current water sector experience - ongoing, active work in water treatment, wastewater or biosolids treatment design
• Degree in mechanical engineering or closely related discipline
• Chartered or Incorporated Engineer status with a relevant professional body, or clear evidence of working towards these professional titles
• SQEP (Suitably Qualified Experienced Person) - recognised as having specific knowledge and experience in mechanical engineering for water applications
• Minimum 12+ years'' mechanical engineering experience in water sector, with significant recent (current) work in water treatment
• Demonstrated expertise in one or more specialist mechanical engineering fields:
  • Water treatment
  • Wastewater treatment
  • Biosolids or sludge treatment
  • Pumping systems design and analysis
  • Chemical storage and dosing systems
  • Asset condition surveys and reporting
• Proficiency in delivering engineering design across multiple work categories and project types
• Expert-level knowledge of:
  • Mechanical design working practices and installation requirements
  • Equipment specification, sizing and selection
  • UK legislation, standards and water sector regulations
  • Pumping system hydraulics and calculations
  • Process and mechanical integration
  • Health, Safety and Environmental compliance
• Strong leadership capability - proven ability to lead engineering teams and manage project workstreams
• Excellent communication skills - confident engaging with clients, partners, internal teams and stakeholders
• Quality and compliance focused - meticulous approach to design quality, documentation and regulatory compliance
• Highly motivated -takes ownership of design delivery and technical excellence

Desirable

• Experience leading mechanical engineering on major water or infrastructure projects
• Familiarity with BIM and integrated design management
• Experience with asset management and condition-based maintenance
• Knowledge of water treatment processes and best practice design
• Experience mentoring and developing junior engineers
• Track record on early contractor involvement or design-build projects
• Fluency with mechanical design software (CAD, analysis tools, etc.)

You''ll work on a hybrid basis with flexible working arrangements. You''ll report to senior engineering leadership and lead mechanical engineering workstreams across multiple water sector projects. You''ll work collaboratively with civil, electrical, process and other engineering disciplines, ensuring mechanical designs integrate effectively with the overall project delivery.

This is senior technical work where your mechanical expertise, leadership and SQEP status directly impact project quality and delivery. You''ll be responsible for design quality, compliance and stakeholder satisfaction. Your decisions on technical approach, equipment selection and design strategy shape how projects are executed.