Legionella are naturally occurring bacteria. They become a health risk when they enter and multiply in water and sanitary systems. The risk of illness from drinking tap water is still low, as Legionella attacks the respiratory tract and is therefore particularly dangerous when inhaled (from steam in the shower and at the sink). However, immunocompromised individuals are at high risk of serious illness. If you detect Legionella in your home's plumbing, you must take action. While measures are being taken to combat the Legionella, suitable shower and sink filters can provide safety.
Legionella in water – What you need to know
What are Legionella?
Legionella bacteria are commonly found in water, especially warm freshwater lakes and streams. They generally only become a health threat when they enter and multiply in water and sanitation systems.
Legionella in drinking water – How do you get there?
Legionella bacteria multiply where temperatures between 20 and 45°C are present and nutrients are present. Below 20°C, these naturally growing bacteria are inactive and do not survive at temperatures above 60°C.
Legionella finds optimal growth conditions in water pipes inside buildings. Water systems, in particular, provide Legionella with a good supply of nutrients, e.g., due to microbial biofilm in water pipes.
Both warm and stagnant water and corroding water pipes provide a favorable environment for the pathogens to thrive. Showers, sinks, toilets, whirlpools, etc. are therefore among the most common sources of Legionella in water.
Legionella and Drinking Water Ordinance
To protect the public from Legionella in water, the Federal Ministry introduced mandatory testing for commercial operators and landlords in 2011. The regulations regarding the testing of Legionella in drinking water installations are laid down in the Drinking Water Ordinance.
According to the Drinking Water Ordinance, most owners of water supply systems are subject to testing requirements. Unless otherwise prescribed, drinking water must be tested for Legionella once a year.
Entrepreneurs or other owners of large-scale drinking water heating systems (e.g. in apartment buildings) must check at least every three years whether the limit values for Legionella in drinking water are not exceeded.
Legionella limit values
The Drinking Water Ordinance sets a limit, the so-called "technical action value." This is 100 "colony-forming units" in 100 ml of water. Any exceedance of this limit must be reported immediately to the responsible health authority.
In the event of a limit value being exceeded, the operator or owner of the water supply system must carry out a risk analysis in accordance with Section 16 Paragraph 7 Number 2 of the Drinking Water Ordinance.
There is also an obligation to immediately inform the affected consumers (e.g. tenants) and to take appropriate measures to protect their health.
How are Legionella transmitted?
Legionella is transmitted through misted and atomized water. In building water systems where Legionella grows and multiplies, there is a risk for humans to inhale the small water droplets containing the bacteria through the air. This can happen, for example, when showering and inhaling water vapor contaminated with Legionella.
Even small amounts of inhaled germs are enough to cause infection with, for example, Legionnaires' disease (a dangerous lung disease) or Pontiac fever.
Are Legionella bacteria dangerous in drinking water?
Legionella bacteria in drinking water can sometimes cause Legionnaires' disease or Pontiac fever. Although this is rare, there is a real risk of choking while drinking water and thus becoming infected.
Normally, drinking water passes through the esophagus into the stomach. However, if swallowed, the water can accidentally enter the lungs. If drinking water is contaminated with Legionella, the bacteria have direct access to the lungs and can cause pneumonia.
Legionella in drinking water is not the most common source of infection for Legionnaires' disease, but it is nevertheless a health risk that should not be underestimated.
What diseases do Legionella cause in water?
Legionella in water can lead to various diseases:
- Legionnaires' disease: This severe form of pneumonia is most commonly caused by Legionella bacteria in water. Signs and symptoms of Legionnaires' disease include cough, shortness of breath, high fever, muscle aches, and headache. Nausea, vomiting, and diarrhea may also occasionally occur.
- Pontiac fever: Pontiac fever is a mild flu-like illness caused by Legionella bacteria in water. Symptoms include fever, chills, headache, muscle aches, loss of appetite, fatigue, and sometimes diarrhea.
- Urinary tract infection: Legionella in water can, in exceptional cases, also lead to a urinary tract infection.
Legionella in water – who is particularly at risk?
For some people, Legionella in water poses an increased health risk. The following risk groups are particularly at risk:
- Middle-aged people, 50 and older
- Smokers and former smokers
- People with chronic lung disease
- Immunocompromised individuals, including those taking immunocompromising
- take medication
- Cancer patients
- diabetic
- People with kidney or liver disease
- Newborns, as their immune systems are still developing
Combating Legionella – What methods are there?
Legionella in water poses a threat to your health. Therefore, you should combat Legionella or prevent its proliferation in drinking water. If you're wondering what you can do to eliminate Legionella, here are some tips:
Legionella in shower head and faucet
Standing water in pipes promotes the growth of Legionella bacteria. For example, if you haven't used your shower in a while, rinse the showerhead with hot water for a few minutes. This reduces the risk of Legionella bacteria in the water. Flush even rarely used faucets weekly. Shower heads should also be cleaned and descaled at least every three months.
Killing Legionella through thermal disinfection
One way to prevent and avoid Legionella in drinking water is through thermal disinfection. This involves preventing temperatures favorable for Legionella growth throughout the entire drinking water system. Legionella can no longer multiply above 55°C. The taps are rinsed with hot water (temperature > 60°C).
...but how effective is thermal disinfection actually?
Thermal disinfection can contribute to killing Legionella to a certain extent. However, it is not an effective method for combating Legionella in water. Furthermore, depending on the bacterial strain, Legionella bacteria exhibit varying sensitivity to heat and, accordingly, to thermal treatment.
Which water filters can I use to prevent Legionella?
To ensure reliable protection against Legionella in water, various water filters are available depending on the area of application.
Legionella filter for the shower
There's a particularly high risk of infection from Legionella in the water, especially in the shower. As described above, Legionella bacteria are spread through water droplets in the air. The spray and water vapor created when showering provide the perfect mechanism for Legionella to be transmitted to humans.
If your water is contaminated with Legionella, you risk inhaling the bacteria and contracting Legionnaires' disease. The risk of the pathogens settling in the lungs and causing significant health damage is particularly high in immunocompromised individuals.
Therefore, if you belong to the high-risk group (see above), we recommend using high-quality Legionella filters such as the Pall-Kleenpak sterile water filter. The Pall sterile water filter is an effective Legionella filter for the shower . Thanks to its double-layer Supor sterile membrane with integrated pre-filtration membrane, this water filter offers reliable protection against microorganisms such as Legionella and Pseudomonas.
The Pall Legionella filter is designed for use at temperatures up to 60°C. The material can also withstand a maximum temperature of 70°C for a total of 30 minutes, making it suitable for thermal disinfection. The robust material is also ideal for chemical disinfection.
Legionella filter tap
Legionella in drinking water can be prevented with the Pall sink filter . This Legionella filter for your sink provides you with clean drinking water that is free of waterborne microorganisms such as Legionella, Pseudomonas, and Cryptosporidium.
You can install the Kleenpak Legionella filter from Pall quickly and easily in your home. This way, you can immediately obtain hygienically clean water or drinking water without interrupting your water supply.
The Pall sink filter can typically be used for the following applications:
- Bathe
- drinking water
- Personal hygiene
- Food preparation
- Ice machines
