What is Legionella?

Female hands under running water in the sink

What is Legionella?

Estimated reading time: 4 minutes

Legionella is the name given to a family of bacteria which cause severe lung illnesses. These conditions include illnesses such as Pontiac Fever, Lochgoilhead fever and the most common one called Legionnaire’s disease. Legionnaire’s disease is predominantly caused by one strain of the bacteria called Legionella Pneumophilla but can be caused by several other strains of the bacteria.



What is Legionella?

Legionnaire’s is a potentially fatal form of pneumonia (around 10% of cases are fatal). The bacterium is typically found in water and can contaminate things such as spas, hot tubs, hot water tanks, showers, air conditioning units and cooling towers. The bacteria like to live in environments where the water temperature is between 20-45°C, especially where there are deposits such as rust, sludge, scale, organic matter or biofilms. This is specially the case in areas where the water is not flushed through and allowed to settle. If left alone, this rarely causes an issue, but when the water is used and if it can cause a fine mist to be created, the water droplets can carry the bacteria into the lungs and cause Legionnaire’s disease. Typically, the illness will not pass from person to person and it cannot normally be caught by drinking water contaminated with the bacteria. It is rare to catch the disease at home.

Legionella Symptoms

Some of the symptoms of the illness are having a high temperature, a cough, muscle pains, shortness of breath and other flu-like symptoms and symptoms will typically occur between 2 and 10 days after exposure. There are some factors which make having Legionnaire’s disease worse such as age, smoking, pre-existing lung conditions or a compromised immune system.

What is Legionella? Finger adjusting temperature on a domestic boiler

Legionella in the Workplace

The legal framework that governs how legionella should be controlled in the workplace comes under the L8 approved code of practice and there are a few steps to robustly controlling legionella:

  • Carry out a risk assessment to identify water systems where the temperature is between 20°C and 45°C, where water droplets can be formed, where the water might stagnate or contain deposits which can support bacterial growth.
  • Once these have been identified control measures need to be put into place and these can include:
    • Keep the water system’s temperature below 20°C or above 50°C. Ensure, though, that the water is not so hot so as to cause scalding when used.
    • Ensure that pipe runs and water storage systems have no dead spots where water can stagnate or where bacteria promoting material can accumulate. Also ensure that any piping systems are as short as possible
    • Prevent contamination in tanks and other water storage systems by ensuring they have lids or are sealed
    • Flush out water systems regularly to keep the water fresh. This could be for taps or shower heads in areas that aren’t used often. Ensure that the system is flushed for long enough to ensure that all the water in the pipes is flushed through
    • Where possible consider treating the water with biocide or ionisation treatments to kill the bacteria
    • Descale water systems regularly
    • In systems where legionella build up is possible, consideration should be made to regularly test the water for contamination to show that the control measures are working

Legionella Training

At Chris Garland Training we have two courses dedicated to Legionella: Our Basic Legionella Management course, aimed at facilities managers and maintenance professionals covers the basic requirements of how to effectively control Legionella in water systems; our Legionella Awareness  course is designed for anyone in charge of a premises, known as the duty holder, to give them the basic awareness of their responsibilities under the L8 legislation.

For any questions on these courses or any of the courses we run, please do contact us either on our website contact page, via email on [email protected] or just give us a call on 01565 746555. We look forward to hearing from you. 


What is Legionella?

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