28 June 2023

Legionellosis is a collective term for diseases caused by legionella bacteria including the most serious Legionnaires’ disease.

Legionella positive test sample

This is a potentially fatal form of pneumonia, contracted by inhaling small droplets of water (aerosols) suspended in the air, which contain the bacteria.

There may be an increased risk from legionella bacteria particularly if there are air conditioners and humidifiers; dead legs (dead end pipes) or long runs of pipe work containing warm water in the water system, and showers.

You may need to:

  • complete, record and revise where necessary a specific risk assessment to identify what precautions are needed
  • make sure that these precautions are taken and are properly maintained, with some needing to be examined and tested at specified intervals
  • provide information and training to staff on what they need to do
  • document your arrangements for preventing injury from legionella, keeping certain records.