[Pseudomonads in a new hospital building]

Testing the piping of a new hospital showed that the drinking water was contaminated with Pseudomonas aeruginosa. Because of pollution the plumbing system was treated with oxidizing biocides and air-water flushing for several times, unfortunately without stopping the bacterial recontamination. The reasons were firstly stagnation due to dead legs in the piping system, oversized pipes, very low water exchange rates and the installation of a catch water system, secondly low flow velocity because of low water pressure. After these sources of recontamination had been repaired, chlorine dioxide sanitization could be stopped successfully