Also known as a water hygiene survey/water hygiene risk assessment/ legionellosis risk assessment, A Legionella risk assessment is conducted based on the following legislation and guidelines:
Health and Safety at Work Act 1974 – Sections 2, 3 and 4;
Control Of Substances Hazardous to Health (COSHH) Regulations 2002 and Amendment 2003 and 2004;
The Approved Code of Practice and Guidance – Legionnaires’ Disease ‘The Control of Legionella Bacteria in Water Systems’;
Minimising the Risk of Legionnaires’ Disease – Technical Memorandum TM13 CIBSE 1991;
Safe Operation of Cooling Towers, B.A.C.S., 1989;
British Standard 6700;
Water Supply (Water Fittings) Regulations 1999 and Water Byelaws 2000, Scotland;
EC Directive relating to the Quality of Water Intended for Human Consumption (80/778/EEC);
Where applicable, the relevant Local Authority Code Of Practice.
Legionella risk assessments are mandatory for employers with more than 5 employees, even where the system is simply one mains supplied cold tap. COSHH regulations require the risk of operating a water system to be assessed.

The process generally involves a surveyor attending site, carrying out a visual inspection of all available pipework, cold water storage tanks, calorifiers / boilers / electric water heaters / other plant, all outlets (wash hand basins, sinks, WC’s, showers, bidets, spray taps, etc etc) to ensure compliance with the above guidelines. An asset register is compiled, simple schematic drawing produced and reccomendations made on bringing the system up to standard where applicable.