Legionella - completely natural and yet a risk

– are natural inhabitants of our soils and drinking water sources,

– are not removed by water utilities

– enter the domestic plumbing system in very low concentrations and

– find ideal conditions for multiplying in the water pipes of buildings.

If Legionella are inhaled in too high concentrations via water vapor or droplets when showering, they can cause serious illnesses such as Legionnaires’ disease (pneumonia) and Pontiac fever.

The Robert Koch Institute counted approximately 1,281 reported cases* of Legionnaires’ disease in Germany in 2020. The number of unreported cases is possibly much higher. CAPNETZ estimates an annual number of cases of Legionnaires’ disease of about 15,000 to 30,000 cases* in Germany.

*Source: blob=publicationFile

CAPNETZ: German Competence Network for Community Acquired Pneumonia

– A multi-layer biofilm forms on the inner pipe wall of domestic water pipes within just one year.

– Biofilm on the pipe wall provides food for Legionella and other germs.

– Every meter of a 3/4-inch pipe provides the habitat for about 6 billion bacteria!

– Biofilm on the pipe wall protects Legionella from the disinfection effect of hot water and chlorine!

Scientists have proven that drinking water contains 10,000 to 200,000 active cells per milliliter!

Germs are normally detected via a smear on a nutrient medium. The result is only of limited significance.

– The smear only shows colony-forming germs.

– The smear only shows germs that require oxygen and a medium temperature.

– A determination of the germ types is not possible.

– Only about 0.1-1 % of the germs form colonies at all.

The so-called flow cytometry is a much more accurate detection method, but very complex and expensive.

Our solutions
How many germs are in my pipes?

To detect microorganisms in drinking water, the smear method, which is over a hundred years old, is still used today. In this process, part of the water sample is smear tested on a nutrient medium, and colonies of germs that form are then counted. Scientists know today that only 0.1 – 1 % of all germs present in water tend to form colonies on a culture medium. This means:

0 Mio.
Bacteria Per Liter Of Water
0 Mrd.
Neuer Keime im Leitungsnetz JEDEN TAG​
0 fach
below the true values are the values on which we base our measures
Other health hazards in drinking water
Blog: Water knowledge
Drinking water hygiene in hospitals

Bacterial contamination of drinking water with Pseudomonas aeruginosa, which can cause wound and urinary tract infections, pneumonia and blood poisoning in immunocompromised persons, was recently detected in the University Hospital Frankfurt.

Drinking water shortage

Have you ever had an unsafe feeling about water hygiene when showering at your holiday destination? With the start of this year’s holiday season, the risk of getting infected with legionella when showering in hotels, AirBnB and holiday flats as well as on campsites is increasing.