• Legionella pneumophila is a rod-shaped bacterium which belongs to the genus 'Legionella'

  • It is naturally occurring in soil and water environments, and multiply rapidly in nutritious environments created by biofilm and sedimen

  • At low temperatures (under 20oC) the bacteria survive but do not multiply, over 60oC the bacteria die

  • Legionella bacteria can only infect your body through inhalation of contaminated water droplets, and flourish under certain conditions;

    • at a temperature between 20-50oC; with optimum growth occurring at a temperature of 37oC

    • in stagnant water; little or no water movement provides an excellent breeding ground for the bacteria

  • Water systems which produce water vapour / aerosols are high risk as they can enhance the spread of bacteria and include:

    • Showers, taps (especially spray taps), and baths

    • Cooling towers

    • Air conditioning units

    • Hot tubs / Jacuzzis


  • Everyone is susceptible to infection, but some people are at higher risk including those who are:

    • over 45 years of age

    • smokers and heavy drinkers

    • elderly and infirm

    • suffering from chronic respiratory or kidney disease, or an impaired immune systems e.g. transplant patients


What are my responsibilities?


The Health and Safety Executive's Approved Code of Practice (L8) provides guidelines for the management of risk of exposure to Legionella, and is recommended reading for all those responsible for water systems. The Health and Safety at Work Act 1974 (HSWA), Control of Substances Hazardous to Health Regulations 1999 (COSHH) and Management of Health and Safety at Work Regulations 1999 (MHSWR) all cite the HSE’s Approved Code of Practice L8.


Health and Safety Approved Code of Practice (L8)

Legionella Bacteria

What is Legionella?