Germs and bacteria in the water

In recent years, reports on Tapwater contaminated with bacteria and germs have steadily increased in Germany (see table below). The fact is that despite rigorous controls, drinking water in Germany is comparatively often contaminated with bacteria and germs.

Whether and how this affects people depends on various factors - such as the type of pathogen, the amount of germs and the health constitution of the individual.
In this Guidebook , we explain how to ...

• ... which types of bacteria and germs are found in drinking water,
• ... how high the burden in Germany currently is,
• ... how contamination with germs and bacteria occurs in the water,
• ... when transmission can become dangerous for humans
• ... and how you can remove germs and bacteria from drinking water.

What germs and bacteria are found in drinking water?

There are many different types of germs and bacteria that can be found in drinking water. The most common include legionella, E. coli and enterococci. These can cause serious health problems, such as diarrhea, nausea or vomiting.

In the graphic below you can see all the germs and bacteria thatare regularly detected in Tapwater . You will then find detailed information on the individual microorganisms.

Legionella

Legionella are aerobic bacteria that are mainly found in fresh water and hot water pipes. They are so-called wet germs that multiply explosively in water under certain conditions. They thrive best at temperatures of 20 - 50 °C. The germs only die at temperatures above approx. 60 °C.

In contrast to most other pathogens, legionella do not cause infections by drinking water, but when they are inhaled. Infection in humans usually occurs through...

• the water vapor when showering,
• tiny water droplets (aerosols) in swimming pools and steam baths,
• the use of air conditioning systems,
  
• or in the vicinity of cooling towers.
  

If Legionella bacteria enter our lungs, this can lead to flu-like Pontiac fever and Legionnaires' disease. The latter is a severe pneumonia that can be fatal. Infants, sick people and the elderly in particular belong to the risk groups.

E. coli and other coliform bacteria

E. coli and coliform bacteria, colloquially known as coliform bacteria, are an indication of contamination of drinking water by faeces. E. coli, short for Escherichia coli, is a group of bacteria normally found in the intestines of humans and animals. Although most strains of E. coli are harmless, there are some that can have serious health effects, including diarrhoea, fever and kidney failure.

Coliform bacteria are often found in the Alps or low mountain ranges, where faecal bacteria can often still be detected in drinking water supplies even after multi-stage conventional treatment by sewage treatment plants . Especially in the summer months, when more cracks form in the dry soil, "germs from faeces" can more easily "overcome the most important filter layer [the humus]", as the Bavarian State Office for Health and Food Safety wrote in a statement on climate change in Bavaria back in 2006³.

Enterococci

Enterococci belong to the group of lactic acid bacteria and occur naturally in certain quantities in the human organism. They are also used in the fermentation and maturing processes of numerous foods. However, some types of enterococci can have serious consequences.

Enterococci are also an indicator of contamination of drinking water by faeces. Such bacteria can enter the groundwater through agricultural fertilizer or farm animal faeces. Heavy rainfall then transports them into the groundwater. However, technical faults in the sewage treatment plant or repair work in the public pipeline network can also transport enterococci into the drinking water.

In people with a weakened immune system, enterococci can lead to infections in various parts of the body, particularly in the urinary tract, but also in the abdomen and heart. In women, it can lead to inflammation of the fallopian tubes or an infection of the bladder.

Wound infections and abscesses are also possible consequences. Treatment is sometimes difficult because some strains of enterococci have developed resistance to antibiotics ⁴.

Pseudomonas aeruginos

A far more dangerous bacterium in drinking water is Pseudomonas aeruginosa, which is found almost everywhere and is a natural component of groundwater sources. Because it is particularly undemanding and able to survive in a wide variety of environments, Pseudomonas aeruginosa can withstand many antibiotics and disinfectants. This makes it a great danger, especially for immunocompromised people, for example in hospitals or care facilities.

The bacterium is therefore particularly well known as a hospital germ with dangerous multiple resistance to antibiotics ⁵. Accounting for around 10 % of all hospital infections , Pseudomonas aeruginosa is one of the most common hospital germs in Germany.

The bacterium can enter the building's cold water pipe network via the service pipe and multiply there in the biofilm - especially in dead pipes or during prolonged stagnation. Once it has established itself in the pipe system of a house, it can only be removed again with costly measures such as chlorine flushing.

In humans, Pseudomonas aeruginosa can cause various infections or pus formation. An infection with the bacterium can lead to serious complications, especially for risk groups with a weakened immune system or pre-existing illnesses, such as

• Pneumonia,
  
• Wound infections
  
• and blood poisoning
  

Although the bacterium is less dangerous for healthy people, it can also cause infections of the skin, nails, hair roots or the cornea of the eye, as well as inflammation of the ear canal.

Multi-resistant germs

Multi-resistant germs are pathogens that have become resistant to drugs such as antibiotics over the course of several generations because they have adapted. This resistance is passed on to the next generation of bacteria. The medication thus becomes ineffective.

Such multi-resistant germs arise because antibiotics are used unnecessarily, too frequently or incorrectly. Multi-resistant germs then enter the environment via wastewater, survive sewage treatment plants and are discharged into rivers with the treated water. The excessive use of antibiotics in factory farming also causes multi-resistant pathogens to enter fields via livestock manure and from there into bodies of water.

We often hear about multi-resistant germs in hospitals, but such germs have now also been detected in rivers and bathing lakes. According to extensive research by Norddeutscher Rundfunk in 2018, it is "largely unknown how heavily contaminated bodies of water are, as there have been no systematic checks for such pathogens to date"⁸.

The antibiotics expert interviewed in the article, Dr. Tim Eckmanns from the Robert Koch Institute (RKI), considers the findings to be "truly alarming". His reasoning: "The pathogens have apparently arrived in the environment and to an extent that surprises me."

Parasites

Parasites in drinking water, especially the parasite species Cryptosporidium parvum and Giardia lamblia, are so-called zoonoses. These are diseases and infections that are transmitted naturally by the fecal-oral route between vertebrates and humans. Cryptosporidia and Giardia are also widespread in Germany⁹.

Extensive investigations by the Baden-Württemberg State Health Office have shown that parasites can be detected in up to 50 % of river, lake and karst waters - albeit in small numbers.

In rare cases, such parasites can lead to epidemics - for example, many years ago in Milwaukee in the USA. There, despite chlorination of the drinking water, more than 400,000 people fell ill with severe diarrhea caused by cryptosporidia¹⁰. More than 100 people even died. Especially in immunocompromised people, such parasite-transmitted diarrhea can also lead to death.

Viruses

Individual viruses can break through the barriers of drinking water treatment and thus reach the consumer via the pipe network¹¹. However, this only affects a small fraction of human pathogenic viruses that enter the water cycle via wastewater or slurry and manure from diseased livestock. These viruses include, for example

• Noroviruses
  
• Rotaviruses
  
• Hepatitis A viruses
• Echoviruses
  

Noroviruses in particular are repeatedly feared in drinking water¹². Transmission via contaminated water is one of the possible routes of transmission of this virus, alongside infection from person to person and via contaminated surfaces, objects or food. Noroviruses are highly infectious, so even the smallest concentrations are sufficient for infection.

Noroviruses are known to cause an acute onset of gastrointestinal flu, which is accompanied by violent, gushing vomiting and severe diarrhoea and can lead to a considerable lack of fluids. In rare cases, symptoms may be limited to either vomiting without diarrhea or diarrhea without vomiting. Often sufferers experience severe abdominal pain, nausea, headaches, muscle aches and fatigue. There may be a slight increase in body temperature, but fever is not usually to be expected.

In principle, the risk of viruses in drinking water to human health depends, among other things, on the type and concentration of the viruses and the state of the immune system. Even a low concentration can be sufficient for an infection under certain circumstances.

The Drinking Water Ordinance does not prescribe any explicit limit values for viruses in drinking water.
It merely states that

Drinking water must not contain pathogens within the meaning of Section 2 No. 1 of the Infection Protection Act that can be transmitted through water in concentrations that give rise to concerns of harm to human health.⁶

Germs and bacteria in Tapwater: incidents in Germany

As German sewage treatment plants are generally not equipped to filter out all germs, there are repeated worrying reports of temporary chlorination of drinking water and requests to boil the water for a certain period of time¹³.

This is the only way to ensure that coliform bacteria, enterococci or even the bacterium Pseudomonas aeruginosa do not pose a risk to humans.

We have collected some of the reports from 2022 and 2023 here:

How do germs & bacteria get into drinking water?

There are various ways in which germs and bacteria can get into drinking water. Here are a few possibilities:

• Contamination of the water source: If the source of the drinking water, such as a lake or river, is contaminated with germs or bacteria, these can pass into the drinking water. Possible reasons for this include waste water, agricultural waste or faeces.
• Inadequate water treatment: If the water is treated in treatment plants to remove impurities, contamination with germs and bacteria can occur under certain circumstances - for example due to malfunctions or inadequate cleaning of the systems.
• Outdated water pipes: The pipe network itself can also be a source of bacteria and germs in drinking water. If the system has leaks, cracks or other weak points, microorganisms can easily sneak into the water.
• Improper storage of drinking water: If Tapwater is stored improperly, for example in dirty containers or at high temperatures, germs and bacteria can form and multiply.

In the summer of 2021, for example, the flooding that occurred in many regions of Germany led to dangerous bacteria from rivers or lakes entering public wells and hundreds of thousands of people having to boil their water¹⁴.

The fact is that up to 200,000 germs can be found in one milliliter Tapwater . However, water is never germ-free, as the Federal Environment Agency states in an article on microbiology¹⁵:

Drinking water is not germ-free. Even after proper treatment, it still contains microorganisms. (...) However, according to the German Drinking Water Ordinance, drinking water must not contain pathogens in concentrations that could endanger human health.

Health effects of bacteria and germs in water

Pathogens in drinking water can be dangerous to humans in two ways. In most cases, people become infected by drinking contaminated water, e.g. Pseudomonas aeruginosa, E. coli or coliform bacteria. A special case, however, is legionella, which infects humans by inhaling water vapor contaminated with legionella - for example in the shower.

How dangerous germs and bacteria are for the human body in individual cases depends on the type of pathogen, the quantity and the state of health of the person concerned. Infants, sick people and the elderly (e.g. in care homes) are among the highest risk groups. The most common symptoms and illnesses caused by bacteria and germs include

• Pontiac fever and Legionnaires' disease (Legionella only)
• Pneumonia and urinary tract infections (with Pseudomonas aeruginosa)
• Gastrointestinal complications (with coliform bacteria)
• Appendicitis and peritonitis (with coliform bacteria)

What to do about bacteria and germs in drinking water?

So there are good reasons to take measures against bacteria in the water. The safest way to protect yourself from unwanted microorganisms is to filter the drinking water. The following options are available:

• Distillation
• Reverse osmosis
  
• Activated carbon
• Ultrafiltration
  

Distillation

Theoretically, bacteria and germs can be removed by boiling water, i.e. by steam distillation.
The procedure is as follows:

• The drinking water is boiled.
  
• The water evaporates and rises to the top.
  
• The pollutants stick to the ground.
  
• Once at the top, the steam condenses and cools down again.
• The condensed water can drip off in an external container.

The disadvantage of distillation: During distillation, the container used must be thoroughly cleaned and valuable minerals are also filtered out of the water during the evaporation process. As a result, healthy substances are lost and the water may taste less good.

Reverse osmosis filter

In principle, osmosis filters are suitable for filtering(coliform) bacteria out of the water. However, osmosis water is not only free from harmful substances such as bacteria and germs. It also contains significantly fewer minerals than water filtered with activated carbon, for example.

The disadvantage of reverse osmosis: the water consumption is comparatively high and valuable minerals are lost with this method.

Activated carbon filter

Activated carbon can filter germs and bacteria to a certain extent. However, this depends very much on the shape of the activated carbon and the design of the filter as a whole. Only in conjunction with other filtration technologies can activated carbon filters remove bacteria and germs from drinking water almost without a trace.

Caution: Activated carbon in granulated form, such as that found in table can filters, is not suitable for filtering germs and bacteria in drinking water!

Ultrafiltration

As activated carbon alone cannot provide sufficient protection against all bacteria and germs, drinking water filters with activated carbon are ideally combined with a high-performance membrane. This so-called ultrafiltration retains bacteria purely mechanically. The pore size is in the range of 0.1 µm - that is 0.001 mm.

This is why these water filters are very effective against acute bacterial contamination in drinking water pipes - 99.99% of the time!

No to germs and bacteria in the water!

Finally, it is important to emphasize once again that germs and bacteria in water pose a potential risk to your health. Due to contamination of the water source, inadequate water treatment, outdated water pipes or improper storage, they can enter your drinking water unnoticed in the blink of an eye.

Especially if you live in an area where there have been repeated problems with bacteria or other germs in drinking water, a water filter can be a great help. A high-quality filter can be permanently installed under the kitchen tap or flexibly attached to the tap or in the shower and continuously ensures good water quality. Don't leave your health to chance, take precautions with a suitable water filter!

Water filter for drinking water - from Alb Filter

Improve your water quality with a high-quality drinking water filter from Alb Filter!

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