Is Your Legionella Risk Assessment Up to Standard?

Ensuring your Legionella risk assessment is up to standard is not just best practice, in many cases, it’s a legal obligation. With water systems providing a potential breeding ground for Legionella bacteria, a robust and regularly reviewed assessment is essential for maintaining workplace water safety and regulatory compliance. Whether you’re managing a small office or a complex facility like a hospital, the quality of your risk assessment could be the difference between safe operations and serious health risks.

In this article, we explore what a Legionella risk assessment entails, who should carry it out, and why assessor competence is so critical. You’ll also learn when assessments should be reviewed, how they fit into broader water safety plans, and how to ensure they remain effective as your premises evolve. If you’re unsure whether your current approach meets legal and safety standards, this guide will help clarify your responsibilities and highlight key areas for improvement.

What is a Legionella risk assessment?

A Legionella risk assessment is a structured process designed to identify, assess, and control the risks associated with Legionella bacteria in engineered water systems. The bacterium can lead to serious illnesses, such as Legionnaires’ disease, if water systems are not properly managed.

The primary objective of the assessment is to ensure that water systems, such as cooling towers, hot and cold water systems, and spas, are maintained in a way that prevents the growth and spread of Legionella.

In the UK, this type of assessment is required by law, and is designed to determine whether a building or facility is safe to use or whether it poses a heightened risk of problems stemming from Legionella bacteria. The organism can be found in natural water sources, but they are also present in engineered water systems which is where they can become problematic. It is virtually impossible to completely eradicate the bacteria, but it is necessary to make sure they do not develop beyond safe levels.

Promoting Legionella safety in the workplace

A Legionella risk assessment is a vital tool to help those in control of the management and safety of a building or facility that uses water. It should identify and assess all potential risk factors within those premises. This forms the backbone of all Legionella risk assessments, and yet not all assessments will be identical. The assessment should reflect each individual building or premises and the risks therein.

According to guidance provided by the Health and Safety Executive (HSE), a Legionella risk assessment must be carried out and updated whenever necessary. This is a requirement under UK Health and Safety law and is set out in more detail in the HSEs ACOP L8 and HSG274 guidance documents. You can see, therefore, that it is not enough to merely carry out a risk assessment. It should be done by someone with the right knowledge and experience to carry out that task.

Further, it should be updated whenever necessary. Even if the original risk assessment was sufficient, circumstances can change that mean it should be repeated. A good example would be if an upgrade or renovation took place in part of the premises. This may incur a change to the water system, which would require the risk assessment to be done again.

Is your Legionella risk assessment sufficient to protect your people?

Is the assessment suitable for the situation? To give an example, a small self-contained office with its own small kitchen and bathroom would have a much simpler water system than a large hospital with multiple buildings and complex water services. This showcases two very different examples, with the latter requiring a far more detailed risk assessment to identify any potential Legionella risks that may be present.

In the case of the small office, someone with common sense and knowledge of the risks imposed by Legionella could likely perform a simple risk assessment. This would note where any potential risks might lie, incurring only the simplest of measures to keep the bacteria under control.

We can see that in the case of the hospital, someone who is qualified, trained, and experienced in the control of Legionella and the latest legislation and guidance should take on the risk assessment. The risks may be different from one area of the hospital to another, depending on the susceptibility of people in these areas and the way water is used.

Suffice to say no two risk assessments can be approached in the same way. They must all consider the surroundings, the people using those surroundings, and the water system and how it works within the space. Only then can the risks be identified, and the steps to control or remove those risks can take place.

How often should you review a Legionella risk assessment?

The basic answer is ‘regularly’ – but of course, that covers a multitude of possibilities. Previously, the HSE’s ACOP L8 document, Legionnaires’ disease: The control of Legionella bacteria in water systems, suggested a two-year review of every risk assessment. However, this was removed – a good decision as it could lead to complacency. The idea that you can review the assessment every two years and then forget about it should therefore be avoided thanks to this change in wording.

In truth, the Legionella risk assessment should be reviewed and checked whenever a change occurs that could mean Legionella has a chance to take over part of a water system. For instance, if any portion of the water system changes, it’s time to review the risk assessment. This might mean noting a new risk factor or identifying an older one that no longer exists. For instance, an old disused bathroom might be removed, therefore removing any risks previously associated with it.

Other risk factors that can affect the risk levels over time include any changes in staff who were previously responsible for helping to maintain water safety or the condition of the system. Obviously, if a suspected case of Legionellosis or Legionnaires’ disease should occur, this also requires a risk assessment update to identify any potential issues.

In short, it is better to conduct a risk assessment for Legionella or updated assessment whenever possible, even if you are not sure whether it is required. The suitability of your assessment and its regularity can also depend on the type of building you are assessing. It is likely that care homes, hospitals, and other such buildings will require a more frequent review than another public buildings that are far simpler and smaller in size.

How to use your Legionella risk assessment

This should become part of your Water Safety Plan – a vital document that allows you to develop the required procedures and monitoring processes to ensure your water systems are correctly run, maintained, and cleaned.

The assessment may identify certain risk factors that can be removed, which is the ideal scenario. In other cases, remedial work may be required, to improve the safety of the water system and make all necessary changes to achieve this.

Good communication is key to successful water safety

Smaller businesses may only have one person handling their water safety requirements. Indeed, this may be all that is required, with simple measures ensuring the safety of the water system. However, the bigger and more complex the business, building or location becomes, the more people will be involved in managing the situation.

Everyone who participates in the Water Safety Group should be communicative, so that everyone knows what is happening, and who is responsible for what. This alone can be a key factor in ensuring the right measures are taken on an ongoing basis.

The Legionella risk assessment is a vital tool, and many will recognise that. However, it is not to be completed and then forgotten about – far from it. It must be compiled by someone competent to do so, and then be regularly checked to see whether any changes are required. This is the only way to ensure it does the job it is intended to do – and that you won’t run into problems along the way.

Expert Water Treatment and Water Safety Solutions

Water Treatment Services provide a comprehensive range of water and wastewater treatment, water quality analysis, consultancy, and water engineering solutions to support business owners and those responsible for the safe and efficient operation of water systems in the workplace.

Contact us today to learn how our water treatment specialists can help you manage your water systems, maintain regulatory compliance, and ensure safe, reliable performance.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South West England and Wales), Leeds (North and North East), and Glasgow (Scotland), supported by regional teams of highly trained technicians and engineers, we deliver specialist consultancy, water quality analysis, engineering support, and risk management solutions across the UK and internationally.