Role Overview: We are seeking a skilled and reliable Mobile Water Hygiene/Treatment Engineer to join our expanding team. Based in London, you will be responsible for carrying out a range of water hygiene, treatment, and compliance services at commercial and industrial client sites. This is a field-based role, and candidates must be willing to travel across the Greater London area and occasionally beyond. Key Responsibilities: Conduct routine monitoring and sampling of domestic and process water systems Carry out water temperature checks, inspection of calorifiers, and cold water storage tanks Clean and disinfect water systems including tanks and showers (chlorination) Conduct closed system analysis (heating and chilled systems) and chemical dosing Assist in the delivery of legionella control measures as per ACOP L8 and HSG274 Perform remedial works such as TMV servicing, descaling, and minor plumbing tasks Complete on-site reports and submit documentation via tablet or company system Liaise professionally with clients, providing advice and updates as needed Maintain equipment and chemicals securely and in line with safety standards Participate in out-of-hours call-outs and emergency response as required Requirements: Essential: Proven experience in water hygiene/treatment or a plumbing-related background Understanding of water hygiene legislation and compliance (ACoP L8, HSG274) Full UK driving licence (clean) Strong communication and customer se