Abstract: A method of configuring an artificial neural network for predicting residual chlorine concentration in water contained in a storage tank of a water supply system, the storage tank having an inlet for admitting water into the tank and an outlet for discharging water from the tank. The method of the invention comprises the steps of (a) collecting historical data representative of selected operational and water quality parameters associated with chlorine demand in the tank; (b) scaling the data collected in step (a); (c) organizing the data scaled in step (b) in the form of a set of time-lagged data; and (d) processing the data organized in step (c) through an artificial neural network by scanning a window over the set of data, the window having a size corresponding to a sub-set of the data, to associate a predicted value with a respective one of the sub-sets scanned by the window, the predicted value being representative of the residual chlorine concentration at the tank outlet.