Legionella regulations – what must you do to comply?

11th November 2020

Legionnaires’ Disease is a potentially fatal form of pneumonia caused by the bacterium Legionella pneumophila, commonly found in potable and HVAC water systems. 

Employers, building and facilities managers and anyone with a health and safety responsibility must comply with relevant legislation to avoid fines, reputation damage and – most importantly – harm to occupants.

Positive legionella samples have increased by around 20% over lockdown compared to the same time last year due to buildings not being used at their capacity.

During these challenging times when public health is at the forefront and building occupancy is changing, legionella compliance and prevention should be a priority.


The Health & Safety Executive’s (HSE) Approved Code of Practice L8: Legionnaires’ Disease – The control of legionella bacteria in water systems (ACOP L8) contains legionella control guidelines – a vital resource for duty holders.

HSG274 Legionnaires’ Disease – Technical Guidance

Formerly part of ACoP L8, HSG274 contains comprehensive practical and technical guidance, published in three parts:

It covers legal requirements under the Health and Safety at Work etc Act 1974 (HSWA), the Control of Substances Hazardous to Health Regulations 2002 (COSHH) and the Management of Health and Safety at Work Regulations 1999 (MHSWR).

What do I need to do?

Under ACoP L8 and HSG274, duty holders need to do the following:

  • Legionella Risk Assessment – thorough identification and assessment of all potential sources of Legionella risk, carried out in accordance with BS 8580:2010 – Water-quality Risk Assessment for Legionella control.
  • Legionella prevention and treatment scheme – keep a prepared copy, in writing.
  • Appoint a ‘competent person’ – appoint a person with the relevant competence, skills and knowledge to help you implement said scheme and manage the risk.
  • Keep clear and comprehensive records – businesses with more than five employees must keep written records; the same is not required of businesses with less than five employees, however, it is advisable to do so regardless. Most records must be kept for 2 years, but results of monitoring inspections, tests or checks carried out must be kept for 5 years.
  • Any other duties – things like notifying the local authority under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992, and notifying cases of Legionnaires’ Disease or other illness caused by legionella under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations (RIDDOR).

Guardian Water Treatment offers a range of legionella control services, helping businesses at every stage of this process; from ACoP L8 compliance, through to ongoing water treatment.

For more information, click here.