A sanitary warm water system comprises an annular water duct (2), a pump (3), heating means (5), withdrawing ducts (7) connected to the annular duct (2) and a supply duct (9), a monochloramine generator (13) which synthesises and adds monochloramine to the warm water in the annular duct (2) at a disinfection point (14), an ammonium ion abatement device (15) which adds chlorine or hypochlorites to the warm water in the annular duct (2), ammonium detection means (17) which detect the concentration of ammonium ions in the warm water and a control system which activates the monochloramine generator (13) and activates the ammonium ion abatement device (15) and controls the addition of chlorine or hypochlorite as a function of the ammonium concentration signals, independently of the activation of the monochloramine generator (13).
