Managing Legionella Post COVID-19 Lockdown

Legionella Risks

Global outbreaks of COVID-19 (Coronavirus) have resulted in the compulsory closure of a number of large buildings such as schools, universities, leisure facilities and office blocks at a scale previously not seen. Now, as these buildings start to re-open after the imposed lockdown, there is a genuine risk that they could have become a breeding ground for another infection – Legionnaires’ disease (Legionella).

The long periods of inactivity in buildings, a result of the COVID-19 lockdown, has greatly increased the risk of the Legionella pneumophilia bacteria developing in large water tanks and pipework. The bacteria survives in the biofilm that gathers on pipe and tank surfaces and likes to feed on the sludge and sediment that builds up there. Legionnaires’ disease, or Legionella as it is more commonly known, is caused by inhaling water droplets, via hot tubs, showers and heating systems that contain the bacteria infected water.

The coincidence of the easing of lockdown measures and the onset of warmer weather conditions has increased the potential for Legionnaires’ outbreaks. The Legionella bacteria flourishes in warm conditions, as the optimum range for the bacteria is between 20-45°C (68-113°F).

Possible Sources of Exposure

Potential Sources of Exposure to Legionella

Quick Facts


A severe form of pneumonia caused by Legionella bacteria. Symptoms of this type of respiratory infection include high fever, chills, cough, muscle aches, headaches and diarrhoea


People over 45, especially smokers and heavy drinkers, or those suffering from a chronic respiratory disease, diabetes, kidney or heart disease or anyone with an impaired immune system


Hospitals, hotels and large office buildings are common locations for Legionella outbreaks and the most common source tends to be the drinking water supply

Health departments reported nearly 10,000 cases of Legionnaires’ disease in the United States in 2018. However, because Legionnaires’ disease is likely underdiagnosed, this number may underestimate the true incidence

Source: CDC – Legionella Fast Facts

Keeping Safe

We recommend that anyone involved in the maintenance of facilities carry out comprehensive risk assessments of all water systems in the premises that they manage, before use of the building returns to normal, or workers start to return to work. There is a general legal requirement in most countries for employers to protect employees and other users of the building from infection involving Legionella Bacteria. Implementing a water management program in large buildings and facilities is a must. Generally speaking, regular and continuous testing should help reduce the likelihood of a Legionnaires’ disease outbreak.

Legionella Kits

If you have responsibility for management of water systems at your facility then our Legionella Kits are designed to make your job easier. One of the primary methods of control over Legionella Bacteria growth is temperature control.

Ensure stored water is either cooled to below 68°F or heated to above 140°F.

KM330P12KIT KM330 Legionella Kit

Legionnaires’ disease (Legionella) cannot be transmitted from person to person. The symptoms will usually present and worsen over a seven-day period. As Legionnaires’ disease is caused by bacteria, it needs to be treated with antibiotics as soon as possible after symptoms present themselves. Delaying treatment could result in severe respiratory failure.

COVID-19 Similarities

The symptoms of Legionnaires’ disease could easily be mistaken for those of COVID-19 as they include fever, dry cough, shortness of breath and muscle pain. Self-isolating is not a recommended course of action however, due to the requirement for prompt antibiotic treatment and because Legionella is not a communicable disease.

Anyone presenting with the symptoms described above, who tests negative test for coronavirus (esp. COVID-19), should be further tested for Legionnaires’ disease and not simply encouraged to recuperate alone.

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