Water suitable for drinking is unsuited for use in the preparation of haemodialysis fluid and undergoes additional treatment. The primary component of the additional treatment is reverse osmosis, which does not remove low-molecular-weight contaminants, and the water treatment system must contain carbon beds or filters to ensure effective removal of such contaminants. The recent article by Bek and colleagues highlights an unrecognised issue with respect to chemicals that may be added to the water within hospitals to ensure that the distribution network is free of pathogens (for example, Legionella, pseudomonas, and mycobacteria) and underlines the need for personnel responsible for dialysis in a renal or intensive care setting to be aware of any potential effects that disinfection of the hospital water treatment system may have on the product water used in the preparation of dialysis fluid. Such awareness requires communication and the sharing of information between clinical and facilities staff.