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Practical advice on controlling legionella bacteria in water systems

25 November 2013

Health and safety information on managing and controlling legionella bacteria in water systems has been updated and clarified.

The Health and Safety Executive (HSE) has revised the Legionnaires’ disease Approved Code of Practice (ACOP) (L8), removing the technical guidance which has been published separately online.

Highlighting the benefits of the change, Lorraine Medcalf, HSE’s Legionella policy lead, said: “The revised ACOP provides greater clarity for dutyholders on what constitutes legal requirements and what is guidance. Where possible we have simplified terminology.

“The review also enabled us to update technical guidance to incorporate technological advancements and separate it from general guidance on the regulations, making it available on our website”.

The ACOP, which is aimed at dutyholders including employers; those in control of premises; and people with health and safety responsibilities for others, was one of several identified for review and revision; consolidation; or withdrawal, in line with a recommendation by Professor Ragnar Löfstedt in his report ‘Reclaiming health and safety for all’.

The revised publication was subject to consultation and received HSE Board and ministerial approval. It includes information on identifying and assessing sources of risk; preparing a scheme to prevent or control risk; implementing, managing and monitoring precautions; keeping records of precautions; and appointing a competent person with sufficient authority and knowledge of an installation to help take measures needed to comply with the law.

The revised ACOP is available on the HSE website at:  

Legal responsibilities to protect workers’ health and safety are not altered by any changes to ACOPs.


Notes to editors

  1. Professor Ragnar Löfstedt’s review of health and safety legislation is available on the Department for Work and Pensions (DWP) website at  
  2. An ACOP provides practical guidance on complying with the general duties of the Health and Safety at Work Act (HSWA) or the requirements of goal-setting regulations. ACOPs are not law but do have a special legal status; if the advice in ACOP material is followed in relevant circumstances dutyholders can be confident they are complying with the law. 
  3. The revised ACOP L8 replaces the previous version, which included technical guidance. The technical guidance is 13 years old and significantly out of date, necessitating a detailed and thorough revision of its content. HSE has worked with the Industry Review Group to revise and update the technical guidance and publish it separately (HSG274). This guidance comprises of three sections – Part 1: Evaporative Cooling Systems, Part 2: Hot and cold water systems and Part 3: Other Risk Systems. It is available at 
  4. The Health and Safety Executive is Britain’s national regulator for workplace health and safety. It aims to reduce work-related death, injury and ill health. It does so through research, information and advice; promoting training; new or revised regulations and codes of practice; and working with local authority partners by inspection, investigation and enforcement.

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