This research adds a method to evaluate control strategies to the design methodology for drinking water treatment plants. A process model dealing with parameters related to the calcium carbon dioxide equilibrium was set up. Using the process model, the existing control strategy was compared with a new control strategy and the effects of two different sets of input data were studied. It was demonstrated that the efficiency of the pellet softening process and the plant's capacity were increased, and that chemicals and energy usage were reduced. At the same time, the deviation of the total hardness of the produced water to the desired value was decreased.