Legionella bacteria can easily proliferate in hot and cold water systems where conditions are right and appropriate controls are not in place. Employers and landlords responsible for building management have a legal obligation to control this risk, through proper assessment, planning and prevention measures.
Legionnaires’ disease is a dangerous condition spread by inhaling microscopic droplets of water contaminated with the legionella bacterium. The bacteria lives in water, thrives in temperatures between 20 oC and 45 oC and grows fast where stagnation is able to occur and biofilm allowed to build up. The disease can be deadly for anyone, but it is particularly dangerous for those in high-risk groups such as the sick and elderly.
The range of measures that can and should be taken include:
Legionella growth is typically controlled in water systems through consistent temperature control.
Those designing and maintaining systems should seek to minimise Legionella growth, by:
Water stagnates when it stands unused for sustained periods and this encourages the growth of legionella bacteria. To prevent this it is recommended those managing water systems:
Depending on the level of risk of bacteria growth and the vulnerability of those using the building, some premises may require additional or alternative risk controls for their hot and cold water systems. These include treating water with:
In these cases there are specific regulatory requirements for maintaining treatment regimes, including weekly, monthly and annual testing to prevent over or underdosing.
The requirements for documenting, monitoring and controlling the risk of legionella growth in hot and cold water systems can be extensive and onerous. Individuals responsible for these duties need the right training to ensure watertight and demonstrable compliance.
Employers, landlords and others with responsibility for managing buildings are required by the Health and Safety at Work Act 1974 to carry out legionella risk assessment and depending on the outcome of that assessment, manage hot and cold water systems in order to control the growth of the legionella bacterium.
The size of your premises, the complexity of your water systems and the vulnerability of the people who use them, will all dictate the extent of the control measures you need to take.
For example, to fulfil these duties in a care home settings, a water safety plan tailored to your specific water system is essential. This plan should include risk assessment, monitoring (regular testing of water samples for Legionella), and control measures such as temperature management, biocide treatments, and physical cleaning
The various assessments and controls required for different kinds of buildings’ hot and cold water systems are detailed in the following technical guidelines:
The code of practice for legionella control:
L8 ACOP Legionnaires’ disease: The control of Legionella bacteria in water systems
Guidelines for hotels, hospitals and other large premises:
Guidelines for those running care homes and the like:
Control of Legionella in hot and cold water systems in care services / settings using temperature
Preventing and treating Legionella in water systems is a critical aspect of building maintenance and public health. Regular maintenance, proper water treatment, and a comprehensive water safety plan are key to keeping Legionella at bay. By understanding the risks and implementing these strategies, we can significantly reduce the likelihood of Legionnaires' disease outbreaks.
Remember, while these guidelines provide a good starting point, it's essential to consult with water treatment professionals and adhere to local regulations and guidelines for managing Legionella risks in your specific context. Stay informed, stay vigilant, and keep your water systems safe.