As Legionella risks continue to rise in the UK, Greg Rankin, CEO of Legionella testing authority Hydrosense, explains how installers can contribute to risk assessment and early detection, playing a crucial role in protecting public health.

Legionella is not a new concern. For decades, this bacterium – responsible for the potentially fatal Legionnaires’ disease – has been present in various man-made water systems, including taps, showers, air conditioning units, pools, and hot tubs. Most industry professionals, including installers, are well-versed in the safety standards necessary to minimise risks during installation and maintenance.

However, recent trends indicate a rising threat due to a combination of factors such as aging infrastructure, climate change, evolving water usage patterns and increasingly complex water systems. This trend is reflected in the increasing number of Legionnaires’ disease cases worldwide. In 2021, for instance, the European Union recorded its highest annual notification rate of Legionnaires’ disease. Similarly, the UK saw a more than 20% rise in Legionellosis cases between 2017 and 2023.

Installers on the front line

 This escalating risk has significant implications for installers. As water system professionals working directly with these infrastructures, installers are uniquely positioned to help detect, prevent, and mitigate Legionella contamination in commercial plumbing systems. This makes it more critical than ever for them to stay informed about the latest detection solutions and best practices to enhance building safety.

Ensuring high Legionella control standards should also be viewed as a matter of self-protection. The UK’s installer workforce is predominantly male, with two-thirds over the age of 45 and more than a third aged 55 or older. Given that individuals over 50 – and men in particular – are at higher risk of Legionnaires’ disease, installers working with unmanaged water systems may be exposing themselves to significant health risks. Thus prioritising Legionella prevention is not just about safeguarding clients – it is also about protecting those who work closely with water systems every day.

As Legionella-related challenges continue to evolve, the argument for proactive engagement in risk assessment and early detection becomes even stronger. But what practical steps can installers take?

Best practice

At first glance the established approach to preventing Legionella growth appears fairly simple – hot water should be stored above 60°C and distributed above 50°C, while cold water storage and distribution should be below 20°C. Infrequently used outlets should be flushed out regularly and showerheads de-scaled and cleaned. Thermostatic Mixing Valves (TMVs) play a key role in this by allowing water to be stored and distributed at temperatures high enough to kill Legionella bacteria, while reducing it to a safe temperature for use by mixing it with cold water.

However, while TMVs are essential for minimising the risk of scalding, they can inadvertently increase the risk of Legionella growth. This is because the blended water downstream of a TMV can create an environment conducive to the bacteria’s multiplication. Ensuring safe TMV use depends on implementing a robust maintenance programme, including regular flushing to prevent water stagnation – a known factor for promoting Legionella. Despite this, the consensus is that TMV maintenance, inspections, and servicing are not necessarily always as thorough as they need to be.

Couple this with the UK’s increasingly intricate water systems and rising Legionella counts and, arguably, there is a clear case to place a sharpened focus on current practices.

Lab limitations

At the same time, at a duty holder level it is clear that there is scope to improve and modernise the standard approach to Legionella testing. For the uninitiated, most duty holders will tend to rely on the lab-culture method, whereby water samples are collected from water systems on site and sent to a UKAS accredited laboratory which will identify the presence or absence of Legionella. However, this approach is timely, cumbersome and has limitations.

Foremost, most lab culture tests take 7-10 days to return results. Yet Legionella can double in a day. This large time lag means increased exposure and risk for installers and the premises they serve. Water samples can also get damaged in the transportation process, potentially killing the Legionella inside and increasing the risk of a false negative result. Lab culture testing is also unable to detect Viable but Non-Culturable Legionella (VBNC) – which though dormant can still be incredibly dangerous due to their ability to resuscitate and reinfect a water system – also being able to directly infect human cells even in their dormant state.

To address these limitations, the latest generation of rapid testing kits enable the detection of Legionella in just 25 minutes and are incredibly accurate at quickly detecting the potentially fatal Legionella pneumophila. Not only does using this method during installation help reduce risk and minimise potential exposure, but it also offers additional information during necessary reviews of risk assessment, and provides peace of mind for the customer.

Proactive inspection

But what exactly, you may ask, does this all mean for the installer? Historically, installers may not have been heavily involved in the realm of Legionella testing. However, as the breadth of Legionella happening in the UK continues to increase, it’s crucial that every possible step is taken to minimise exposure and risk for the British public. Being out on the front line and with a deep expertise of water systems, it makes sense for installers to play a much more active role in Legionella risk assessment and detection to help in this.

Put bluntly, this presents a huge opportunity. By proactively monitoring and identifying potential Legionella breeding conditions and advocating for and even conducting regular rapid inspections of water systems as part of existing works, installers can help to reduce liability risks for the commercial clients they serve. As part of this, installers could even provide on-site rapid testing as part of an installation or maintenance package.

The benefits of this are twofold. Foremost, proactive inspection efforts can not only help to ensure safer water systems for everyone but create a new revenue stream for installers. Also, amid growing awareness about Legionella and the need for more robust preventative measures, those early adopters of this approach will be more likely to gain market share as demand increases – especially in industries with heightened health and safety priorities.

For further information please visit: https://hydrosense-legionella.com/