The paper reports initial results for experiments carried out at Fortore drinking water treatment plant aimed at controlling chlorites. Research was performed in parallel with a full-scale drinking water plant (Fortore, Italy) and a pilot plant at Mosina water treatment plant which supplies potable water to the city of Poznań (Poland). Both plants operated with pre-disinfection via chlorine dioxide. In Fortore, a small quantity of free chlorine in ClO2 solution was present that yielded low amounts of THMs formation. Pilot scale GAC filters were installed in both plants in order to assess the efficacy of different GAC types for chlorites removal. Results of pilot-scale experiments performed in two large water treatment plants: Mosina Water Treatment Plant located near Poznań (Poland) and Fortore Water Treatment Plant South Italy) was compared in order to assess suitability of GAC for chlorites removal from water as stated by National European Directives. Main objectives of this paper were to study the efficiency of ClO2- removal as a function of GAC columns height and to evaluate the influence of the temperature in GAC performance in chlorites removal Results showed an increase of the chlorites GAC removal as function of the temperature.