Understanding the Increasing Threat of Legionella: Risks, Causes, and Prevention
Recent data from the Legionellosis in Residents of England and Wales: 2017-2023 report by the UK Health Security Agency (UK HSA) highlights a concerning upward trend in cases of Legionella-related illness. Since 2022, the report highlights the UK has seen a significant increase in reported cases, with 604 instances recorded in 2023—the highest number to date.
As these cases continue to rise across the UK, we ask Jemma Tennant, Chair of the Water Management Society and SMS Environmental Technical Consultant, to provide her perspective on the recent report from the UK HSA. She highlighted key challenges driving the trend and the need for balanced public health and sustainability efforts.
Key Insights from the Latest Report:
- Community-acquired infections make up the majority of cases.
- The demographic most affected continues to be men (70.2%), with those over 60 (64.2%) at the greatest risk.
These figures highlight the urgent need for enhanced water hygiene and safety in both public and private sectors. The rising risk of Legionella calls for proactive measures from businesses and property owners to safeguard their buildings and occupants. Compliance with health regulations and bacteria-free water systems is essential.
Legionella Cases on the Rise: Contributing Factors
Hazel Henderson, Public Health Scotland, states that the rise in Legionella cases maybe influenced by a combination of enhanced testing, environmental changes, and technological advancements.
Enhanced Surveillance: More Testing, More Cases
Better surveillance has led to more Legionella cases being detected, particularly in Scotland and England. While increased testing is beneficial for public health, it highlights the need for improved management of water systems, especially those serving vulnerable populations. Addressing environmental and design factors is crucial to tackling the growing risks.
Net-Zero Push and Water Systems
Efforts to reach net-zero carbon emissions are contributing to Legionella risks. Energy-efficient technologies like solar heating and heat pumps often cannot maintain the high temperatures needed to prevent Legionella growth. As bacteria thrive in water between 20°C and 45°C, eco-friendly systems that cannot heat water above 60°C create an ideal breeding ground.
Changing Building Occupancy
The shift to hybrid work models has reduced water demand in commercial buildings, leading to stagnant water in pipes. With buildings designed for higher occupancy, this stagnation increases Legionella risks. Addressing reduced water usage is critical to maintaining safe water systems.
Vulnerable Ageing Population
As life expectancy increases, more elderly individuals, who are more susceptible to Legionella, are living in communities. Additionally, long-term COVID-19 effects leave many with weakened immune systems. Facilities serving at-risk populations must prioritise water system maintenance to safeguard against Legionella.
Global Warming and Rising Water Temperatures
Warmer temperatures due to climate change increase the risk of Legionella, a harmful bacteria that thrives in water systems. Mains water is now more likely to exceed the 20°C threshold considered safe for preventing Legionella growth, and rising energy costs make it more difficult to maintain the necessary hot water temperatures.
Balancing energy efficiency with Legionella prevention has become an ongoing challenge.
To prevent Legionella, we need to keep cold water cold and hot water hot—and we need to keep it moving. However, many of the systems designed to reduce water usage, such reduced flow showers and taps, can inadvertently lead to water stagnation, creating an ideal breeding ground for bacteria.
Mitigating the Risks: A Call for Better Water Management
Proactive water system management is essential to prevent Legionella growth. This involves regular risk assessments, proper system design, and ongoing maintenance to ensure water safety.
It’s crucial that building designers, managers, and maintenance teams understand the risks and take a proactive approach to Legionella prevention. This means ensuring systems are properly designed, regularly assessed, and well-maintained to keep water systems safe, efficient, and under control.
Balancing Sustainability and Safety
Efforts to increase sustainability must not inadvertently raise Legionella risks. Proper temperature control, minimising stagnation, and maintaining water flow are essential for safe water systems. Building designers, facility managers, and maintenance professionals must stay informed and adjust strategies to balance sustainability with health and safety.
Sustainability and Safety Must Go Hand in Hand
As we adopt new technologies for energy efficiency and water conservation, we must ensure that proper safeguards are in place to protect the safety of our water systems. With increased awareness, proactive management, and a balanced focus on both sustainability and safety, we can continue to make progress toward a healthier, more sustainable future.
While sustainability is vital, it’s essential that we don’t compromise public health in the process. Energy-efficient systems and water-saving designs should never create conditions that promote Legionella growth. Balancing innovation with vigilant water management is key to creating safe, sustainable buildings for all.
At SMS Environmental, we have long been at the forefront of advocating for stringent water hygiene protocols. This includes regular testing, thorough risk assessments, and robust preventive measures to safeguard public health. Legionella bacteria thrive in poorly maintained water systems, and the risks to vulnerable groups must never be overlooked.
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References:
UK Health Security Agency -Legionellosis in Residents of England and Wales: 2017-2023 [2024
