Avoiding Legionella contamination in your hot water
Avoiding Legionella contamination in your hot water
If you manage a hospital, hotel or own any heating system read our tips how to avoid Legionella.
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What is Legionella?
Legionella bacteria in water systems
Drawing 1. A 3D visualization of Legionella pneumophila
How does Legionella breed?
How to fight with Legionella
Legionella in systems can be eliminated using a chemical or thermal method. In clean systems that are free from biofilms, the Legionella bacteria don’t reproduce as much, hence the importance of correct design and execution of the domestic hot water system. You can prevent proliferation of bacteria in water supply systems by employing correct technical solutions:
- At draw-off points, the temperature of usable water should range above 55°C.
- Ensure that the water is periodically heated to 70–80°C in order to perform thermal disinfection.
- Use a domestic hot water circulation system.
- Eliminate discontinuities in thermal insulation and replace one that is used up, damp or does not meet the requirements with new insulation that has an appropriate thickness and as low heat conductivity as possible.
- Periodically disinfect hot water pipes.
- Properly balance the system in order to eliminate zones with too low flow rates which pose the threat of dangerously lowered temperatures or water stagnation.
- Eliminate the so-called “dead ends”. If such branch-offs cannot be excluded, the water inside them must be periodically overheated.
- Ensure proper technical and sanitary condition of the system.
Highest number of Legionnaires’ disease cases ever reported in 2014
With 6 941 cases reported, the rate of Legionnaires’ disease in the EU/EEA in 2014 was 13.5 cases per million, the highest ever observed. This is in line with the increasing trend observed over the 2009–2014 period, notwithstanding the large community outbreak that occurred in Vila Franca de Xira near Lisbon, Portugal, in 2014, which contributed substantially to the high number of reported cases. Further investigations, such as an analysis of meteorological conditions favourable to Legionnaires’ disease, may explain the other reasons for this increase.
France, Germany, Italy, Portugal, and Spain accounted for 74% of all cases. You can find a list of Legionnaires' disease outbreaks here