How great is the risk of legionella in cold water?
Created: 10/05/2022, 2:00 p.m
By: Franziska Kaindl
Due to rising energy costs, savings are being made in numerous households - some even on hot water.
But does this increase the risk of legionella?
Saving energy is the order of the day in many households.
There are many options, from heating to energy-guzzling devices to lighting, consumers can come up with many ideas to keep costs down this winter.
Many also see savings potential in hot water.
However, experts warn against legionella.
What are legionella?
According to the Federal Center for Health Education (BZgA), legionella are environmental germs that are distributed all over the world and are a natural component of surface water and groundwater in small numbers.
According to the Robert Koch Institute (RKI), they can also be found in moist biotopes, such as in mixed soil for potted plants or in compost.
In their natural ecosystem, legionella normally do not cause any problems - they only become relevant to health when they appear in technical facilities such as drinking water systems or sewage treatment plants and aerosols are formed there that are contaminated with legionella.
Legionella can be absorbed by aerosols in the air.
© Norbert Schmidt/Imago
What diseases are caused by legionella?
Legionella cause two different clinical pictures in humans:
Legionnaires
' disease , also known as legionellosis or legionella pneumonia, is a form of pneumonia.
Symptoms include cough, chills, headache, feeling very sick or high fever.
If left untreated, it can become severe.
If it is discovered and treated in time, the chances of recovery are good.
Pontiac fever
: This is an acute febrile infection without pneumonia.
Those affected usually suffer from mild flu-like symptoms, including headaches and body aches, chest pains and a dry cough.
The symptoms usually subside after a few days without antibiotic treatment.
People with a weakened immune system are particularly affected, for example due to an illness or medication, as the RKI reports.
People with underlying diseases such as diabetes mellitus or chronic heart/lung diseases also become ill more frequently.
There are also smokers and the elderly.
It affects men two to three times as often as women.
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How do you become infected with Legionella?
The pathogen is transmitted by inhaling atomized, nebulized water, as the BZgA informs.
This is usually the case when showering, in whirlpools or in connection with humidifiers.
Infection occurs less frequently when legionella are ingested through drinking water, since the bacteria in the stomach are killed by the gastric acid.
An exception is when the contaminated water accidentally gets into the trachea and not the esophagus.
These viruses and bacteria make us sick
View photo gallery
When do legionella multiply in water?
In order to ban the risk of legionella at home, the temperature of water should always be above 50 degrees Celsius - according to the RKI, growth is then effectively inhibited.
From 60 degrees Celsius, the germs die off.
Temperatures between 25 and 45 degrees Celsius should be avoided, as these offer ideal growth conditions for legionella.
The bacteria can also be found in cold water, but at temperatures below 20 degrees they no longer multiply significantly.
"Make sure that the warm water is always at a temperature of at least 55 degrees Celsius everywhere in the pipe system.
This is the only way to reliably prevent legionella growth.
It would be a health risk to save energy here,” advises the Federal Environment Agency (UBA).
The water should ideally have been heated to 60 degrees before it comes out of the pipe warm, according to information from the German Association for Gas and Water (DVGW), among others.
"It's not so much about the temperature as it leaves the shower, it's about the temperature in the storage tank itself or in the pipes," says Benedikt Schäfer from the Federal Environment Agency, according to
Deutschlandfunknova
.
Thanks to a mixer tap, the water on the tap can be regulated to a comfortable temperature again.
