Site Supervisor - Mechanical AP
MWH Treatment
April 11, 2026
Full-time
On-site
Rickmansworth, Hertfordshire, United Kingdom
Management & Supervision
We are looking to strengthen our Construction team with a Mechanical AP Site Supervisor based with in the Thames Region.
You will report directly to Senior Commissioning Manager and your role will supervise and control all mechanical site activities in the most efficient manner, to the specification and within the contract time without risk to the health and safety of all concerned and providing a quality end product, ensuring a Quality installation with all ITP,s completed as the work progresses. You will be required to undertake a mechanical appointed person(AP) assessment & be able to hold that position.
Key responsibilities will include:
- Support the Site Manager in maintaining a safe working environment for all employees, supply chain partners and visitors;
- Ensure that all relevant HS&E documents are correctly recorded and reviewed when received and that they are the latest version;
- Check that all relevant documents adequately describe the work to be carried out;
- Review and comment on Method Statements and Work Instructions as required by the Project Execution Plan;
- Manage mechanical permits, hot works permits & client issued permits
- Supervise work to ensure that it is carried out in accordance with Method Statements and Work Instructions;
- Record the progress of the works on record drawings or other suitable means when required;
- Record all non-conformance and improvement opportunities and agree action with the person in charge of the works.
About You
Knowledge/Experience:
- Several years experience of working in the Water sector. Understands pipework fabrication, welding and erection. Recognises quality welding. Can punch and snag mechanical works in accordance with Isometric, GA and P&ID drawings effectively.
- Previous experience in a mechanical AP role, issuing mechanical permits & managing mechanical works
Education/Qualifications
- HNC / HND in Mechanical Engineering or good apprenticeship in pipework and welding along with experience
- SSSTS
- CSCS
- First Aider
About Us
MWH Treatment is an integrated design and build provider working in the water sector. With over 1400 staff working across eight regional centres, supporting six long-term water sector frameworks and two recently won frameworks, operating both as a sole contractor but also in joint ventures and alliances.
At MWH Treatment we believe that people matter. We know to build successful, creative teams we need a diverse workforce that can deliver innovative ways of thinking. We provide an environment where you will have the freedom to develop and grow to your full potential, creating opportunity by inviting, embracing, and celebrating difference, our goal as an employer is to motivate, and develop our employees. By fostering a diverse range of talents and perspectives we ensure we have the breadth of viewpoints, experiences, and skills needed to succeed. Embracing diversity of all kinds enables us to provide a work environment and culture that plays a key role in attracting and retaining the right people with the right skills.
As signatories to the Armed Forces Corporate Covenant, we have made a promise to support our forces, working with the CTP to help ex veterans find work in the civilian world. We also support Mates in Mind, a charitable programme to improve and promote positive mental health in the workplace. We don’t just tick boxes; we live these values every day.
What MWH offer
Packages include -
A competitive salary
Hybrid Working (Jobs needs dependent)
Car/car allowance (Jobs needs dependent)
25 days holiday + Bank Holidays (with an additional 5 days available to buy)
Contribution Pension scheme
Life Assurance
Health Insurance
Private Medical Insurance
And many more benefits including – cycle to work scheme, discounts and savings Hub, Kids Pass etc
At MWH Treatment we believe that people matter. We know to build successful, creative teams we need a diverse workforce that can deliver innovative ways of thinking. We provide an environment where you will have the freedom to develop and grow to your full potential, creating opportunity by inviting, embracing, and celebrating difference, our goal as an employer is to motivate, and develop our employees. By fostering a diverse range of talents and perspectives we ensure we have the breadth of viewpoints, experiences, and skills needed to succeed. Embracing diversity of all kinds enables us to provide a work environment and culture that plays a key role in attracting and retaining the right people with the right skills.
As signatories to the Armed Forces Corporate Covenant, we have made a promise to support our forces, working with the CTP to help ex veterans find work in the civilian world. We also support Mates in Mind, a charitable programme to improve and promote positive mental health in the workplace. We don’t just tick boxes; we live these values every day.
What MWH offer
Packages include -
A competitive salary
Hybrid Working (Jobs needs dependent)
Car/car allowance (Jobs needs dependent)
25 days holiday + Bank Holidays (with an additional 5 days available to buy)
Contribution Pension scheme
Life Assurance
Health Insurance
Private Medical Insurance
And many more benefits including – cycle to work scheme, discounts and savings Hub, Kids Pass etc