Mechanical Supervisor - Southampton

MWH Treatment; Southampton; On-site; GBP 42,000 - 54,000; Full time

Job summary

MWH Treatment is seeking a Mechanical Supervisor for Southampton to lead on-site mechanical installations as part of the CMDP+ joint venture. You will oversee installation teams, ensure SHE standards, and deliver high-quality work aligned with current specifications.

Ideal candidates hold an HNC or higher in Mechanical Engineering and have water/wastewater site experience, with SSSTS/SMSTS and AAW membership to support safety and quality on site.

Qualifications

• HNC or higher in Mechanical Engineering.
• Previous water/wastewater site experience (preferred).
• SSSTS or SMSTS certification.
• AAW membership within a relevant professional Qualification.

Responsibilities

• Supervision of site mechanical installations.
• Ensuring SHE standards are maintained and safe systems of work are followed.
• Ensuring a high-quality product in line with standards and specifications.
• Attend site inductions and toolbox talks.
• Ensure mechanical safety rules are adhered to and documentation is produced.
• Carry out regular mechanical safety inspections on equipment.

Skills

Water/wastewater site experience

SSSTS or SMSTS

AAW Membership

Education

HNC or higher within Mechanical Engineering

Job description

Mechanical Supervisor - Southampton

2026-09-26T00:00:00

Southampton

Hampshire

GB

SO14 7

Any

2026-12-25T07:01:24.583

Mechanical Supervisor - Southampton Job Description

CMDP+ is looking for a Site Supervisor (Mechanical Bias) to join our Southern Water Framework. MWH Treatment and Costain Group are part of the CMDP+ joint venture that will deliver a range of construction schemes to maintain and improve Southern Water's water supply and wastewater treatment works within the South and Southeast regions.

At Costain, we believe diverse perspectives drive innovation. If you're passionate about making a positive impact and think you can bring value to our team, we'd love to hear from you - even if you don't tick every box. Your unique skills and experiences could be exactly what we need.

Responsibilities

• Supervision of site mechanical installations
• Ensuring SHE standards are maintained and safe systems of work are being adhered to
• Ensuring a high-quality product is being produced in line with current standards and specifications
• Attend site inductions and toolbox talks
• Ensure mechanical safety rules are adhered to and supporting documentation is produced in line with CMDP mechanical safety rules
• Carry out regular mechanical safety inspections on temporary and permanent equipment
• Assist with compilation

Knowledge, Skills, and Experience: Essential

• HNC or higher within Mechanical Engineering discipline
• Previous water/wastewater site experience (preferred)
• SSSTS or SMSTS
• AAW Membership within a relevant professional Qualifications

About Us

Costain helps to improve people's lives with integrated, leading edge, smart infrastructure solutions across the UK's energy, water, transportation and defence markets. We help our clients improve their business performance by increasing capacity, improving customer service, safeguarding security, enhancing resilience, decarbonising and delivering increased efficiency.

Our vision is to be the UK's leading smart infrastructure solutions company. We will achieve this by focusing on blue chip clients whose major spending plans are underpinned by strategic national needs, regulatory commitments, legislation or essential performance requirements.

We offer our clients leading edge solutions that are digitally optimised through the following five services which cover the whole lifecycle of their assets: future-shaping strategic consultancy; consultancy and advisory; digital technology solutions; asset optimisation and complex programme delivery.

Our culture and values underpin everything we do. Costain appreciates the time and effort taken when applying for one of our positions but, due to the high volume of responses, we are unable to provide individual feedback on candidates at the application phase. We do share individual feedback following an interview.

A Disability Confident employer will generally offer an interview to any applicant that discloses they have a disability and meets the minimum criteria for the job as defined by the employer. It is important to note that in certain recruitment situations such as high-volume, seasonal and high-peak times, the employer may wish to limit the overall numbers of interviews offered to both disabled people and non-disabled people. For more details, please go to the Disability Confident website.

The Team: CMDP is a joint venture between Costain and MWHT and delivers a range of schemes to maintain and improve Southern Water's water supply and wastewater treatment works in the eastern half of its region (Kent & Sussex).