Legionella and Legionnaires' Disease

This site provides information on Legionella and how to control risks from exposure to Legionella from man-made water systems in the workplace.

What is Legionella?

Legionella bacteria are common and can be found, usually in low numbers, in water sources such as rivers, reservoirs and lakes.  As legionella bacteria are encountered in natural environmental water sources they may eventually colonise in manufactured water systems and particularly hot and cold water systems, cooling towers and other equipment and plant that stores water.   

Legionnaires' disease is normally contracted by inhaling legionella bacteria either in droplets of water or ingestion of contaminated water.  It can lead to a potentially fatal form of pneumonia which can affect anyone, but more so the elderly, those already suffering an illness and smokers.

What are the symptoms?

The symptoms are similar to those of flu, i.e. high temperature, fever and chills, cough, muscle pains and headache. In a severe case, there may also be pneumonia, and occasionally diarrhoea, as well as signs of mental confusion. Legionnaires' disease is not known to spread from person to person.

Are there Legionella risks in my workplace?

There may be a risk of exposure to Legionella if your workplace or premises has:

Further guidance on how to control legionella risks in the workplace can be obtained from the Health and Safety Executive.

Duties of Employers, Controllers of Premises and Landlords

  • identify and assess sources of legionella risk
  • manage any risks
  • prevent or control any risks
  • keep the correct records
  • carry out any other duties you may have

Further details of how to manage risks and carry out a risk assessment can be obtained from the Health and Safety Executive.

Some cases of Legionellosis are reportable under RIDDORFurther guidance can be obtained from the Health and Safety Executive.

Controllers of premises have a duty under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992 to notify the local authority in writing with details of 'notifiable devices'. Further details on how to do this can be found on our Cooling Towers and Evaporative Condensers website.


Useful Information

Information for leisure centres with spa pools, care homes and other organisations that use hot and cold water systems for bathing and washing or in manufacturing processes.