Legionellosis in England & Wales: Key 2024 Insights

The UK Health Security Agency (UKHSA) has published its Legionellosis in Residents of England and Wales: 2024 official statistics, providing a comprehensive overview of Legionnaires’ disease across the two countries. The report offers valuable insights into incident rates, trends, and risk factors, highlighting both progress in controlling the disease and areas where vigilance remains essential. 

Legionnaires’ disease is a severe form of pneumonia caused by Legionella bacteria, which are naturally present in water systems but can become a health risk when they grow in man-made water systems such as cooling towers, hot and cold water systems, spa pools, and decorative fountains. While the disease is relatively uncommon, it can be serious and even fatal, particularly for older adults and individuals with underlying health conditions. Understanding the latest statistics is essential for public health, building operators, and anyone responsible for water safety.

Key findings from the 2024 report include:

• A total of 472 legionellosis cases were reported in 2024, representing a 22% decrease compared with 2023 and returning to levels similar to those seen in 2021–22. This decline may reflect improved awareness, water safety management, and public health interventions.
  
  

• The incidence rate of Legionnaires’ disease dropped to 0.7 cases per 100,000 population, down from 1.0 in 2023. This figure confirms the disease remains relatively rare, though vigilance is still required given the potentially severe outcomes.
  
  

• The majority of cases continue to affect older adults, with people aged 60 and over accounting for nearly two-thirds of reported cases. Men represented 68% of cases, consistent with previous years. These demographics underline the importance of targeting high-risk populations for prevention and early diagnosis.
  
  

• Just over half of all exposures were community-acquired, while a significant proportion were linked to travel abroad. A smaller share of cases was associated with healthcare settings. These findings highlight the diverse environments in which Legionella exposure can occur and the need for robust water system management across sectors.
  
  

• The case fatality rate (CFR) for 2024 was 2.8%, similar to the previous year. This emphasizes that while most people recover, Legionnaires’ disease can still have serious consequences, particularly if diagnosis or treatment is delayed.
  
  

The 2024 data also underline the seasonal nature of Legionnaires’ disease. Cases are typically higher during the warmer months when conditions are more favourable for bacterial growth in water systems. UKHSA recommends ongoing monitoring, regular maintenance of water systems, and prompt investigation of any suspected outbreaks to minimise risk.

For organisations responsible for water safety — including healthcare providers, residential facilities, hotels, and public buildings — the report serves as a reminder that effective water management plans and adherence to control measures remain critical. Regular Legionella risk assessments, routine water testing, and Legionella training are key components in preventing Legionella growth and protecting public health.

The 2024 report is a valuable resource for anyone involved in water hygiene management, public health, or policy planning. By examining trends, demographics, and sources of exposure, stakeholders can identify priorities for prevention and intervention, ensuring that the risk of Legionnaires’ disease continues to be reduced.

📄 Read the full UKHSA report for detailed data and analysis. — Published 20 November 2025