Controlling and preventing legionella growth is essential to minimise the risk from this potentially harmful bacteria.

Legionella thrives in certain conditions, so it is important to identify the risk first, and then to modify or change these conditions to kill any legionella bacteria, and prevent further growth.

What Contributes to Legionella Growth?

Legionella lives and grows in biofilm. Biofilm is a deposit of bacteria, fungi and algae and it grows and thrives in water systems, appearing as slimy deposits inside pipework.

Why are man-made water systems so attractive to legionella?

  • They may include sections where stagnant water lies and where biofilm then builds up.
  • They can contain and transmit warm water, at temperatures that encourage bacterial growth.
  • Where water systems are continually wet, this can encourage the growth of legionella.
  • If the system emits fine droplets of water, this can lead to airborne transmission of the legionella bacteria.

This makes it essential to maintain water systems and related equipment.

External factors may also contribute to the spread of legionella, such as construction or interruptions or changes to the water supply.

How Harmful is Legionella Bacteria?

The legionella bacteria can cause various pneumonia-like illnesses, and the most well-known of these is legionnaires’ disease.

It infects the lungs and if it is not treated, it can prevent them from functioning properly. In certain cases, people with legionnaires’ disease suffer a severe bacterial reaction that leads to sepsis.

This illness is potentially fatal, and it can infect anyone. However, certain groups are more at risk of developing severe symptoms than others.

These groups include:

  • People aged 45 or over
  • Smokers and heavy drinkers
  • People with chronic respiratory disease, kidney disease or cancer
  • People with weak immune systems.

What Methods Will Kill Legionella Bacteria?

Legionella likes water temperatures between 20°C and 45°C. Water within this temperature range can encourage rapid bacterial growth.

Water that has not been adequately treated can also encourage the growth of legionella, through the build-up of biofilm.

Therefore, the two main ways of killing legionella bacteria are:

  • Managing water temperatures, and
  • Applying an effective water treatment.

Managing Water Temperatures

To kill legionella bacteria and minimise legionella risk, you should maintain water systems at temperatures that avoid the dangerous temperatures in which bacteria thrive.

In simple terms, your cold water should be cold, below the 20°C threshold, and your hot water hot enough to be consistently 50°C or hotter.

But other conditions encourage legionella growth, such as stagnant, slow-flowing or contaminated water.

This is where water treatment using hydrogen peroxide is an effective way to kill legionella.

Hydrogen Peroxide in Water Treatment

Hydrogen peroxide is a proven disinfectant for water treatment. This chemical compound disintegrates quickly, generating free radicals that oxidise and disinfect the water.

This leaves behind no trace of chemical residues, but it will kill legionella.

Oxyl-Pro uses aseptic grade hydrogen peroxide to treat water systems, removing and preventing biofilm build-up in pipework.

Oxyl-Pro quickly kills bacteria, helping to control and prevent the spread of legionella.

For more information about legionella prevention methods and water treatments, please call us on +44 1606 851 782, email or complete our contact form.