Summary Background Patients receiving haemodialysis are exposed to a large volume of dialysis fluid. The Italian Society of Nephrology (ISN) published guidelines and microbial quality standards on dialysis water (DW) and solutions to ensure patient safety. Aim : Aim of the study was to identify microbial and chemical hazards and to evaluate disinfection treatments quality in DW plants. Methods: In the years 2015 and 2016 water networks and DW plants (closed loop and online monitors) of nine dialysis wards of Italian hospitals, hosting 162 dialysis beds overall, were sampled on a monthly basis to determine the parameters provided by ISN guidelines. Chlorinated drinking water was desalinated by reverse osmosis and distributed to the closed loop which feeds all online monitors. Disinfection with peracetic acid was performed in all DW plants on a monthly basis. Findings: During the entire study period of 24 months 7 out of 9 DW plants (78%) recorded negative results for all investigated parameters. A closed loop contamination of Burkholderia cepacia was detected in a DW plant from January 2015 to March 2015. Pseudomonas aeruginosa was isolated from March 2016 to May 2016 in the closed loop of another DW plant. These microbial contaminations were eradicated by shock disinfection with sodium hypochlorite and peracetic acid, followed by water flushing. Conclusion: Our results highlight the importance of chemical and physical methods of DW disinfection. The maintenance of control measures in water plants hosted in dialysis wards ensures a microbial risk reduction for all dialysis patients.