Legionella Risk Assessment

IWM specialise in providing clear and concise Legionella risk assessments, for a wide range of healthcare, industrial and commercial clients.

Our risk assessment system complies with the requirements of British Standard BS 8580 Water quality – Guide to risk assessments for Legionella Control. However, we also supply simple and to the point summary reports as the sometimes long and wordy risk assessment documents required by standards and guidance are needed but not always the easiest for determining what action to take. Summary reports can focus on what you need to know, so you can see where you need to prioritise your remedial actions and what you have to do to comply with the regulations.
Our risk assessors are highly experienced, as there is surprisingly no standard qualification required to be a Legionella risk assessor it is worth enquiring on previous assessment experience for a premises similar to that requiring assessment.

IWM use an external software based risk assessment system, that has been used to create over 12,000 risk assessments.

Water hygiene (Legionella) risk assessment in Healthcare

Guidelines for the Prevention and Control of Infection from Water Systems in Healthcare Facilities advocates Water Safety Plans and risk assessments of water systems.

The UKs Department of Health HTM04-01: 2015 Part B was also updated to include WSPs and a more overall safe water throughout the premises approach.

This requires Legionella risk assessment to be woven into assessments on scalding risks, and other bacteria for example pseudomonas and any chemical risks from secondary dosing.


It is imperative that a competent person with the relevant skills, knowledge and experience carries out the risk assessment. Industrial Water Management Ltd maintains membership with the Legionella Control Association for carrying out risk assessments. (Certificate hyperlink)

Legionella Risk Assessments – Commercial buildings

We are often asked, “Do we need to complete a Legionella risk assessment?”
The intent and purpose of the Safety, Health and Welfare at Work Act 2005 is protection of the health of employees from hazards arising from work-related activities or workplace conditions. Nevertheless, in any given building, it is clear that Legionella exposure risks apply, not only to workers, but also to others present at the workplace who may be affected by virtue of the work

The National Guidelines for the Control of Legionellosis in Ireland: 2009 makes it clear that the UK ACoP L8 should be read in conjunction with Irish guide as it is not in itself definitive.
The UK ACOP L8 indicates that a suitable and sufficient risk assessment is the first step in Legionnaires’ Disease prevention. The objective is to identify all water systems where legionella bacteria could potentially grow and assess the risk of people being exposed to contaminated aerosols from them. All water systems need to be included in the legionella risk assessment.

Legionella Risk Assessments – Industrial process & cooling water

At the end of 2013 the Health and Safety Executive in the UK released HSG 274 Part 1. The control of legionella bacteria in evaporative cooling systems.

Among many changes in the guidance is the ability to drive the need for cleaning and disinfection from an assessment of the actual internal conditions and degree of water treatment control.

The risk assessment should consider all aspects of operation of the cooling system and should be specific to the individual system under review. Consult site personnel who manage the systems to determine current operational practice. The commissioning, decommissioning, periods of operation, maintenance, treatment and subsequent management of each individual aspect of operation will require review and validation to ensure site procedures are effective.

IWM believe that cooling systems can only be effectively assessed by individuals who have extensive water treatment experience of evaporative cooling systems.

Legionella risk assessment reviews

How often do I need to update my Risk Assessment?
The National Guidelines for the Control of Legionellosis in Ireland: 2009

The UK ACOP L8 legionnaires risk assessments should be reviewed regularly and specifically whenever there is reason to suspect it is no longer valid.
The guidance used to say that a legionella risk assessment should be reviewed at least every 2 years but now it says the risk assessment should be a living document which must be regularly reviewed to ensure it remains up to date.

For a simple system the risk assessment review may be a straight forward confirmation of previous findings. For more complex systems or those that have changed significantly it is probably best to carry out a complete re-assessment.