The Health and Safety Executive publish the Approved Code of Practice (ACoP) L8 - The control of legionella bacteria in water systems and the guidance document HSG 274, both of which are available from HSE books. More info

If the property where the water system is installed falls under the Health and Safety at Work etc.. Act 1974, then yes, any domestic water system within requires a legionella risk assessment under the Control of Substances Hazardous to Health Regulations 2002. More info

There is a guidance document provided by the Deparment of Health called HTM 04.01 that details the considerations required for legionella control in healthcare premeis. More info

Legionella bacteria will die within two minutes at 60°C or above. Therefore, all water heaters with a capacity greater than 15 litres should be able to heat their entire contents to greater than 60°C. 60°C is recognised as a pasteurisation temperature for legionella. More info

In order to be able to demonstrate that your water systems are effictively managed, your site logbook should contain; Management structure and contact information, your legionella risk assessment, an up to date schematic of the water system, your written scheme, procedures for emergencies and a record of the monitoring and maintenance tasks identified in your written scheme. More info