What a Legionnaires' Disease Risk Assessment Must Include

by Water Hygiene Centre, on 22-06-2017
Find me on:

What a Legionnaires' Disease Risk Assessment Must Include

Here, we review what a Legionnaires' disease risk assessment should include as part of an effective Water Safety Plan and to comply with regulations and guidance documents, in order to minimise the risk of legionella proliferation in water systems within buildings.

If you are the Responsible Person [Water] or the Authorised Person [Water] for the estate or building management of healthcare organisation / provider, this essential Blog is aimed at helping you understand a little more of what a Legionella risk assessment must include.

New call-to-action


What we already know about Legionella Risk Assessments!

The concept of Legionella risk assessments is nothing new!  The approaches to completing a risk assessment and what it should include can vary greatly.  When working with clients invariably we review the assessments they’ve commissioned with contractors or consultants, it never ceases to amaze we find the same failing:

  • A subjective assessment where there is no risk scoring matrix or it is illogical;

  • A condition survey ‘badged’ as a risk assessment;

  • A catalogue that lists every outlet [with photos];

  • Unworkable time scales / priority order of recommendations;

  • Not all risk systems are included i.e. Air Handling Units, hydrotherapy pools and those other risk systems listed HSG 274 part 3.

  • Failure to consider occupant susceptibility;

As we have seen in our previous article, it’s important to consider carefully your choice of water hygiene company, keeping the delivery of Legionellosis risk assessment separate from the contractor who undertakes the remedial work arising from the assessment.  It is worth noting this is not an exhaustive list of failings detailed above.


Read more about what is a legionella risk assessment, Mistakes to Avoid and Frequency >


Identification, assessment and review of risks

The HSE reissued ACoP L8 in November 2013 with supporting HSG274 suite of guidance documents:

The ACOP L8 and HSG274 suite of documents, offers advice on managing water systems. Including the need to carry out a risk assessment, as such identifying the risks and how to control them. 


The HSE have detailed a checklist in each of the HSG274 documents outlining the most common key requirements when assessing risk [we are not going to duplicate the lists here] although some of the more interesting requirements include:

  • Details of management processes;

  • An assessment of competence of this involved in the management, control and monitoring [inc. training];

  • Identification of roles and responsibilities;

  • Evidence of proactive management and follow up to the previous risk assessment;

  • An assessment on the validity of the schematic diagram;

You can see that risk assessments are not just looking at water systems! Consultancies who offer risk assessment must ensure the requirements detailed in the HSG274 checklists are included in their risk assessment methodology.

The Department of Health [DoH] has also prepared guidance in the form of ‘HTM04-01: Safe Water in Healthcare Premises’.  The specification of what a risk assessment should include mirrors that of the HSE guidance.  There are however, additional elements detailed by the DoH, such as:

  • Susceptibility of those exposed to water;

  • Clinical practices with water contact to patients and their invasive devices;

  • Disposal of blood, body fluids and patient waste-water;

  • Other devices such as ice machines & water chillers;

  • Unnecessary use of flexible hoses.

To further compliment the guidance, the HSE & DoH refers to ‘BS8580-1: 2019 Water quality. Risk assessments for Legionella control’ published by BSi.  This standard is applicable to any premises where any work activity where water is used or stored that could cause a reasonably foreseeable risk of exposure to legionellae.  The methodology of the standard covers risk assessments completed for the first time, review and auditing of control measures.

Risk assessments completed to ‘BS8580-1: 2019 methodology must consider the following:

  • An assessment of:

    • occupant susceptibility;

    • management processes;

    • processes for monitoring data;

    • record keeping;

    • Inherent risk and actual risk.

  • A defined score matrix [although one is not defined in ‘BS8580-1: 2019];

  • A.L.A.R.P. [as low as reasonably practicable];

Again this is not an exhaustive list, but here we’ve highlighted the need to consider occupant susceptibility [this should be considered by building, systems, departments].  With previous risk assessments completed, the objective was always to get to low risk or no risk, which wasn’t always achievable, to this end BS8580:2010 has introduced As Low As Reasonably Praticable [ALARP].  A more pragmatic approach to ensuring each risk system is being managed appropriately.


Legionella Risk Assessment Forms – the outputs

Risk Assessment  Remedial WorksAfter completion of the assessment process, the assessor(s) must produce a risk assessment report outlining imminent dangers, highlight the differences between the inherent risk and actual risks, the risks for each system should then be compared to their target ALARP i.e. based on susceptibility. The risk assessment report is more of an executive summary.  The main output being the risk minimisation scheme, which contains detailed recommendations, listed in order of priority and identification of who is responsible for the recommendation. 

The risk minimisation scheme report can include ‘many’ recommendations, these recommendations and the priority order should be reviewed and agreed by the Water Safety Group [WSG].  Subsequent implementation of the risk minimisation scheme should be updated at future WSG providing an informed position on the status of risk minimisation.



In this blog we’ve highlighted issues with current Legionnaires' disease risk assessments and their failures. 


There is guidance from the HSE, DoH and BSi when it comes to risk assessments and what they should include.  The appointment of a consultancy to complete your risk assessment is one where the competency and experience needs to be evident and they remain impartial from provision of remedial works.  This blog has detailed the sources which outline what a risk assessment should include so they are suitable and sufficient.


If you have questions regarding the issues raised above or you would like to speak with one of our consultants please click here to get in touch.

Editors Note: The information provided in this blog is correct at date of original publication - June 2017. 

© Water Hygiene Centre 2019

water safety for healthcare

About the author

Water Hygiene Centre

The Water Hygiene Centre was established in 2009 to address the lack of independent water hygiene consultancy within the industry. From our humble beginnings, we have established ourselves as a market leader, helping clients identify and minimise the risk of waterborne contamination and disease, whilst improving compliance performance.

Share your thoughts