If you are someone in control of premises, you must understand the health risks associated with legionella.
Thanks to forum member Trout39843 who has provided some useful water testing record sheets.
Duties under the Health and Safety at Work etc Act 1974 (HSWA) extend to risks from legionella bacteria, which may arise from work activities. The Management of Health and Safety at Work Regulations (MHSWR) provide a broad framework for controlling health and safety at work. More specifically, the Control of Substances Hazardous to Health Regulations 2002 (COSHH) provide a framework of actions designed to assess, prevent or control the risk from bacteria like Legionella and take suitable precautions.
You can find more information on the HSE website HERE
The HSE provides an Approved Code of Practice (ACoP) with regards to Legionella. Download the HSE ACoP