Back to School: Managing the risk of Legionella

Are our washrooms ready for the return to school? Having adapted rapidly to lockdown conditions, re-opening facilities is more complex. Whether buildings have been partially or fully closed, a major concern is Legionella prevention. During lockdown, certain toilets or sinks may have been out-of-action, and with social distancing, this could continue for the foreseeable future. Any mothballed point-of-use has an increased risk of Legionella contamination.

Occurring naturally in water, Legionella bacteria develop in standing water that has a source of nutrients, such as biofilm in pipes or rusted water storage tanks. They multiply at 20-45°C and can be harmful if inhaled in aerosol form.


The solutions are simple: prevent water from reaching temperatures where bacteria multiply (see table 1) and limit water stagnation. If there is evidence of contamination or stagnation, and if the hot and cold water have not been used for a long time, Health and Safety Executive guidelines state that the system should be cleaned, flushed and disinfected. Subsequent regular, flushing will minimise the risk of further contamination. However, manual flushing is labour intensive and expensive.

Technical Solutions

DELABIE’s electronic controls have a pre-programmed duty flush which prevents stagnation. An automatic rinse activates every 24 hours after the last use, running for 60 seconds. The solenoid valve is piston-operated, replacing a traditional diaphragm which can trap water and harbour bacteria. It is possible to install one electronic control at the end of a pipe run without switching to electronic controls throughout: battery-operated taps are easy to install and will automatically flush the pipework, preventing stagnation. User hygiene is also optimised as they operate without manual contact, preventing the spread of germs. 

Hygiene is likely to remain firmly on the public health agenda. Understanding the risks and installing products specifically designed to meet these challenges makes it easy to overcome the risk of contamination.