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EWP: How many legionellae dwell in residential buildings?

In the May issue of energy | water practice, expert magazine of the energy and water industry, first results from the status analysis of the Institute for Hygiene and Public Health of the University of Bonn (ihph) on the occurrence of Legionellae in drinking water installations were published. The great numbers of tests that were assessed lead the authors to one question: How many drinking water installations are subject to testing nationwide?

The ihph-status analysis had to deal with an enormous volume of drinking water data. 1,020,000 data sets were aggregated and assessed. It has been the wolrd’s largest research work on Legionella in domestic drinking water installations with central heating.

Elicitations were conducted with laboratories and drinking water monitoring contractors (n > 1 Million sampling results). Aims of the current project were the development of a systematic, hygienic-microbiological status analysis for the presence of Legionella in drinking water plumbing systems, explicitly including commercially used drinking water plumbing systems, the inductive and explorative examination of risk factors for Legionella and the estimation of the hazard potential.

The technical threshold level for Legionella (100 colony forming units (CFU) in 100 ml water) was exceeded in 5.6% of all samples (n=1,020,328). In 16.5% of all buildings (n=100,213) at least at one tap (sampling point) an exceedance of the technical threshold level was detected in the years 2012 to 2015. The water temperature was observed to be an important risk factor for culturally detectable Legionella (rs=-0.22; p=<0.001; n=502,009).

The article (written in German) can be downloaded here.

ewp-article Legionella in residential builidngs by Becker-Kaiser/Pikarek

Drinking water check-ups for legionella offered to enterprises re-opening their offices

Due to covid 19 many industrial, commercial and public buildings have not been used for several months. Since the numbers of new infections with the corona virus have been going down lately companies take a shot at re-opening their businesses. If in the facilities re-opening now drinking water installations have not been in operation or have not been flushed in certain intervals water stagnation may have led to exponential growth of biofilms and - along with that - pathogenic bacteria such as pseudomonas aeruginosa and legionella in the pipes. 

We offer all firms (before re-opening) a thorough check-up of the drinking water for legionella and other pathogenic germs to attractive conditions. Do not hesitate to ask us. We work for German industries as well as for Anglo-American companies from commercial and industrial branches that run subsidiaries in Germany.



Although coming from the housing sector we have seen an increase in business relations with industrial  enterprises. Before the German drinking water directive passed the Bundesrat firms of the producing and processing industry have always been very sensitive for safety issues. Labor protection laws ordered them to have the water used or processed tested for potentially pathogenic bacteria.

Gas leak detection with GAS-Control

WATERcontrol has evolved from the "big sister" GAS-Control GmbH, a specialist for preventive gas safety checks within builidngs. GAS-Control has worked for the German housing industry for 25 years.

To detect gas leakages, even on concealed lines, the firm operates with portable gas leak detectors that pinpoint tracers of natural gas where they escape from the pipe.