Corrosion in water distribution systems was studied to gain a better understanding of the processes and to develop control strategies. Equations and calculation methods for determining the pH(sub s) were developed using a chemical model with and without ionic speciation. Several calculation procedures for determining pH (sub s) were analyzed and compared. Laboratory experiments using weight loss and electronic techniques for measuring corrosion rates were conducted in laboratory batch and continuously circulating systems using waters with different water quality parameters. Changes in water quality were monitored in experiments with mild steel, galvanized steel and copper coupons. Corrosion products obtained from coupons exposed to continuously circulated solution were analyzed by wet chemical techniques and x-ray diffraction. Results indicate Saturation Index cannot be used alone to indicate the extent of corrosion or to measure the corrosivity of a water.