The drinking water sampled from taps that were publicly accessible – that is, excluding private homes or offices – has about a 50 percent chance of being rated “poor” or “very poor,” the survey by broadcaster ARD and safety certification firm TÜV Rheinland has found.
Of 50 water sources sampled in 10 major German cities, half showed microbial contamination. This included E.coli, Coliform and Legionella bacteria.
ARD said it had informed all of the seriously affected buildings. It had no information, however, on where the sources of the infections lie.
The tests were taken for a documentary programme to be broadcast by ARD on Tuesday at 9:50 pm.
The results followed recent concerns over the quality of tap water in the Berlin district of Spandau and the neighbouring city of Potsdam. Three dead mice and a dead mole were believed to be the trigger for the warning by health authorities in mid-July that residents of Potsdam should boil their water.
High levels of coliform bacteria – of which E. coli is one variety – had been found. At least 3,700 households were forced to boil their water for up to several weeks.
Authorities in Spandau gave the all-clear at the weekend after chlorinating the water supply but said the cause of the coliform contamination remained a mystery.