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Principal Mechanical Engineer


Job Location:

Bristol - UK

Monthly Salary: Not provided by the employer
Posted: 1 October 2026 (2 days ago)
Application Deadline: 29 December 2026
Vacancies: 1 Vacancy

Job Summary

Internal applicants are welcome


Mott MacDonald Bentley have been named a capital delivery partner on two multi-million-pound lots that will see the company deliver projects across the region through to 2030 - with the potential for a five-year extension into AMP9 thereafter.


Wessex Water serves 2.9 million customers with water and sewerage services across the southwest of England. Set for record investment in AMP8 more than double that of AMP7 MMB will bring its strong track record of innovation and direct-delivery to drive a programme of work. We will be delivering schemes located around Bournemouth Poole and South Dorset area.


As a Principal Mechanical Engineer you will contribute to projects that significantly impact our environment and communities. Working primarily in the UK water market MMB provides the feasibility design construction and commissioning services needed to keep water flowing and wastewater treated. Youll work on projects that make a real difference to our environment and our communities by enhancing the efficiency and effectiveness of water and wastewater treatment systems.


You will play a pivotal role in shaping the mechanical functions throughout the lifecycle of various projects.


The role of a Principal Mechanical Engineer includes:

  • Lead and oversee the design planning and execution of the mechanical engineering aspects of our projects.

  • Provide technical expertise and guidance to our mechanical engineers and project teams. Develop knowledge and excellence within the team.

  • Mentor and develop junior engineers and team members.

  • Lead the development of the mechanical design of water and wastewater infrastructure and non-infrastructure projects through the project lifecycle encompassing P&IDs valve schedules pumps tanks process equipment above ground pipework lifting and access steelwork

  • Coordinate with the wider design team of Electrical Civil Geotech and Process engineers.

  • Work closely with the project teams to ensure applications of clients asset standards and engage in particular technical discussions on best practice and standards waivers.

  • Working closely and collaboratively with the commercial operational and construction teams to develop efficient practical and safe solutions throughout design stages construction and beyond

  • Positively engage with the client managing relationships and adopting a one-team approach to supporting them in achieving their aims.


What youll need:

  • Chartered Mechanical Engineer or above

  • Degree in Mechanical Engineering or related field

  • Strong knowledge of the water and/or wastewater industry

  • Strong knowledge of mechanical engineering principles practices and standards relating to process industries.

  • Excellent communication leadership and problem-solving skills.

  • Proven ability to manage multiple design tasks and meet deadlines.


Whats in it for you:

Financial wellbeing

  • MMB match employee pension contributions between 4.5% and 7%.

  • As an independently owned business we share the financial success of the business with all our colleagues including our annual bonus schemes.

  • Payment of annual professional institution subscription costs

Health and wellbeing

  • A minimum of 33 days holiday each year inclusive of public holidays with the ability to buy sell or carry over annual leave through our flexible benefits programme.

  • Access to Life Assurance / Private Medical Insurance / Critical Illness Insurance and Health Screening options

  • We are happy to talk openly about flexible working and how we can support your responsibilities beyond the workplace.

  • Join a wide range of groups including our Advanced Employee Networks which support our LGBTQ gender race and ethnicity disability and parents/carers communities.

Enhanced family and carers leave

  • Enhanced family leave policies including 26 weeks paid maternity and adoption leave and two weeks paid paternity/partner leave plus the option for shared parental leave.

  • Up to 2 paid additional days leave are provided for those with significant caring responsibilities

Learning and development

  • MMB are committed to empowering our people to grow professionally and thrive in their careers. We offer structured development schemes that support your journey toward professional chartership. From day one employees are fast-tracked towards chartership reviews and benefit from mentorship hands-on experience and tailored training opportunities


**Mott MacDonald Bentley are not currently offering sponsorship to candidates under the Skilled Worker visa route in the UK. This decision is as a consequence of the changes made to the Skilled Worker route by the UK Government in April 2024. We continue to welcome applications from candidates who are eligible for alternative immigration routes in the UK that do not require sponsorship as a Skilled Worker now or in future.**




Required Experience:

Staff IC