Legionella bacteria growth temperatures
Legionella bacteria growth and spread depends allot on water temperature within a facility potable water network. As the graphic shows, the ideal growth ranges for Legionella bacteria can easily fall directly in line with the typical domestic hot water (DHW) temperatures or point of entry (POE) water temperatures in warmer geographical areas such as the Southern USA, Central & South America, The Middle East and parts of Asia.In colder climates, such as the Midwest & Northern USA, Canada, Europe, and parts of Australia, domestic hot water needs to be kept at or below 120°F at point of use to avoid potential scalding and conserve energy. This again aligns with the ideal growth range for Legionella.
As a result, these scenarios present a relatively higher risk of Legionella exposure compared to Legionella bacteria growth temperatures below 68°F (20°C), and secondary potable water treatment is required. Copper Silver Ionization (CSI) technologies provide effective long term and effective Legionella growth prevention and remediation to protect facility occupants against the risk of exposure.
The most effective strategy to combat Legionella is to prevent its growth in the first place. This can be done by implementing secondary water disinfection such as copper silver ionization and ensuring that all hot water systems are adequately maintained and monitored. Hot water tanks and other associated equipment should be regularly inspected for leaks or any signs of corrosion, scale or sediment. In addition, water should be maintained at the right temperature, ideally between 55-60 degrees Celsius. This is the temperature at which Legionella will not thrive, but where other bacteria can still live and multiply. However, these temperatures can be logistically challenging to maintain at distal points of use and why secondary disinfection should be continually implemented.
Building owners and managers should consider maintaining a logbook or database of work done to the potable cold or hot water system. Information such as data related to Legionella bacteria growth temperatures, water network inspections, plumbing maintenance, and water testing results are all important to keep track. This will help to identify any potential future issues or warning signs relating to Legionella, as well as allowing a quick response if an outbreak were to occur.
See more about the differences between POE and DHW solutions here