School Still Closed? Monitor your Hot Water System to Prevent Legionella Bacteria

The Covid-19 pandemic had prevented schools in England from re-opening, caretakers have been furloughed and hot water systems are lying dormant encouraging water system stagnation and potentially increasing the risk of Legionnaires Disease.

Legionella, which causes the lethal Legionnaire’s Disease is a potentially serious form of pneumonia contracted when you inhale droplets of water from a contaminated water sources and can be caught when bacteria gets in the water supply.  

The Health and Safety Executive (HSE) recently produced guidance on the risk of legionella following the Covid-19 outbreak stating “if you are an employer, self-employed or in control of premises (e.g. a landlord), you have a duty to identify and control risks associated with legionella. If your building was closed or has had reduced occupancy during the  outbreak, water system stagnation may occur due to lack of use, increasing the risks of Legionnaires’ disease”.

With headteachers uncertain as to when schools are likely to re-open, a DfE spokesperson said: “While schools are partially closed, school buildings and grounds still need to be looked after to ensure they remain functional and safe. Schools are responsible for their health and safety measures and statutory compliance with regulations – this includes water safety management”.

Schools have re-opened in Wales, yet sadly three schools have had to close again in Blaenau Gwent after bacteria that can cause Legionnaire’s disease was found in pipes (bbc.co.uk).

So what can you do?

It is evident that when you leave water systems switched off, they are more likely to breed legionella bacteria, therefore it would be safer to leave the system switched on and monitor it.

According to the HSE, controlling water temperature is the primary method in reducing legionella growth and temperatures should be as follows:

  • Hot water storage cylinders (calorifiers) should store water at 60°C or higher
  • Hot water should be distributed at 50°C or higher (thermostatic mixer valves need to be fitted as close as possible to outlets, where a scald risk is identified).
  • Cold water should be stored and distributed below 20°C.

At Ver Facil, we can help schools to monitor the temperature of their stored hot water and alert head teachers or facility managers if it drops below 45 degrees centigrade for more than 24hrs.

Our LoRaWAN temperature probe is an easily installed, wireless means of monitoring the water temperature in your water system – basically, the probe can be strapped or bonded to hot water cylinders, flow pipework and end of line pipework and when linked to an internal LoRaWAN gateway provide constant monitoring of the temperature in your water system.


This system can be set up so that you can receive alerts when:

  • the hot water cylinder outlet drops below 50
  • the hot water return and outlet temperatures drop below 40
  • the temperature is less than 40 degC for more than 24hrs.


The constant monitoring combined with the alerts means that you will know as soon as the temperatures drop outside of the acceptable range and fix it before risking legionella bacteria growing and spreading through your water system ... and what is more …. it’s affordable!

Contact Ver Facil today on 01208 811277 or office@verfacil.co.uk for more information.