Due to the current situation with COVID-19, many places of work such as hotels, leisure facilities, offices, dental clinics and hairdressers have had to temporarily close with only essential businesses staying open.

As a result, the control of Legionella Bacteria may not be considered a priority and control measures may be neglected. It is vital that businesses reopening consider control measures and make every effort to ensure water storage systems are maintained.

Legionnaires’ disease is a potentially fatal form of pneumonia with symptoms very similar to COVID 19. The illness usually starts with flu-like symptoms including fever, tiredness, headache, and muscle pains. This is followed by a dry cough and breathing difficulties that may progress to a severe pneumonia.

People may become infected when they breathe in tiny water droplets (aerosols) or droplet nuclei (particles left after the water has evaporated) contaminated with elevated concentrations of Legionella bacteria. Legionella bacteria grow best between temperatures of 20°C–45°C with optimum growth temperature being 35°C–40°C. High temperatures (minimum 60°C) kill the bacteria. Legionnaires’ disease can affect anyone. People with immuno-suppressed systems, the elderly or people suffering from respiratory problems may be particularly vulnerable.

See The HSA document for the "Control of Legionella Bacteria During and After the COVID-19 Pandemic" here.... 

The primary method used to control the risk from Legionella is water temperature control.
Water services should be operated at temperatures that prevent Legionella growth these may well have been turned off during the COVID-19 Closure.

  • Hot water storage cylinders 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.

Routinely check, inspect and clean water systems, in accordance with the risk assessment.

HH Solutions have a Range of Legionella Test Kits for the monitoring and testing of water. View our Temperature Test Kits Here....

Monthly checking of the distribution temperatures at outlets closest and furthest from storage tanks is recommended. You should also check the hot water storage cylinder temperatures every month and cold water tank temperatures at least every six months.

Stagnant water favours Legionella growth. To reduce the risk you should remove dead legs/dead ends in pipe-work, flush out infrequently used outlets (including shower heads and taps) at least weekly and clean and de-scale shower heads and hoses at least quarterly. Cold-water storage tanks should be cleaned periodically and water should be drained.


There are on average about 10 cases of legionnaires disease reported each year in Ireland. It can affect all age groups but it is more common in those over 50 years of age. Smokers, heavy drinkers and those with chronic illnesses whose immune systems are weakened are also at greater risk. Males are at higher risk than females. (Source HSE Environmental Health Service, Date of Issue: January 2009)

Read More here....

Particular attention should be paid to premises or parts of premises that operate on a periodic basis (e.g. closed or partially closed hospital wards, seasonal hotels, hostels etc.) In these situations a full maintenance and cleaning programme should be carried out on the water system/air conditioning system prior to reopening.

HSE HPSC Cautions to Be Aware and Prepare to Prevent Legionnaires’ Disease;

Media Release 18th May 2020

Legionnaires disease is a type of pneumonia which causes serious illness in people aged over 50 years, smokers, and those with underlying health conditions. Legionnaires Disease and the milder form, Pontiac fever, a flu-like illness, are caused by the growth of Legionella bacteria in water systems which are not adequately managed.

During the Covid-19 pandemic, many buildings have been closed, or their use restricted. This can increase the risk of Legionella growth in the water systems and associated equipment including evaporative air conditioning systems, water fountains, showers, spa pools, and other equipment if the water systems have not been managed adequately.

Dr Suzanne Cotter, Specialist in Public Health Medicine, HSE Health Protection Surveillance Centre explains: Read More here...



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