How Often Should a Legionella Risk Assessment Be Carried Out?

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Do you know how often you should perform a Legionella risk assessment for a commercial or public building in the UK? Do you know why you need to perform them in the first place and what diseases are caused by Legionella bacteria? If you don’t know the answer to any of these questions, don’t worry as you’ll find all of the information you need right here. Let’s tackle these questions in reverse order so you understand why you need to perform risk assessments and what the dangers are if you do not.


What Diseases Can Legionella Bacteria Cause in Humans?

Legionella bacteria may cause a number of different diseases, all of which come under the umbrella term Legionellosis. There are two main types of disease that the bacteria frequently causes in the UK, one of which is non-pneumonic and one of which is pneumonic:


  • Pontiac Disease – This is the main non-pneumonic form in the UK: a flu-like virus that normally lasts for 2-5 days and is not known to be fatal.
  • Legionnaires’ Disease – This is the main pneumonic form in the UK, the one that makes all the headlines whenever there is an outbreak. It can cause a range of symptoms, from nothing more than a mild cough, to severe pneumonia symptoms and death.


There are other diseases it may potentially cause but they are not commonly encountered in this country.


Why Do You Have to Perform Legionella Risk Assessments?

Low levels of Legionella bacteria can be found in virtually all bodies of water around the world, including lakes, rivers and streams. Due to the open nature of these environments, the bacteria does not normally pose a serious health risk. However, in a closed environment such as a commercial air conditioning system, the bacteria can quickly multiply until it reached dangerous levels of concentration.


How Often Should a Legionella Risk Assessment Be Carried Out?

The Approved Code of Practice published by the HSE in the UK recommends regular reviews of risk assessment procedures for all public buildings and commercial premises. It goes on to specify 2-year intervals in between assessments for buildings with a low risk factor. However, if any substantial changes are made to a building, this should precipitate an immediate reassessment.


If you would like to discuss your Legionella risk assessment procedures with one of our experienced specialists, please do not hesitate to call or message us now.

This article was written by Andrew