[Microbial contamination of drinking water by a polyamide feedpipe]

An incident is described with high colony counts in the drinking water from a well. The well was disinfected with sodium hypochlorite for several times, but without permanent success. After that the search for the reason of the high colony counts started. It turned out that the polyamide rising-pipe produced the microbial growth. Besides the colony increase in the water there was a microbial growth upon the surface of the polyamide pipe as well. When a high grade steel pipe was installed instead of the polyamide pipe there was no colony increase in the water any more.