0011-4561 Theoretical basis of prognosing the failures in water supply systems Theoretical basis of prognosing the failures in water supply systems Iwanejko Ryszarda author Instytut Zaopatrzenia w Wodę i Ochrony Środowiska, Wydział Inżynierii Środowiska, Politechnika Krakowska Correspondence to: Ryszarda Iwanejko 13 02 2012 Środowisko Zeszyt 2-Ś (23) 2012 2012 127 137 Copyright © 2012 2012 <p> Water supply systems are an important element of a strategic urban infrastructure. Their configurations are usually complex and dynamic. The optimal operation strategy of the water supply system should consider both current conditions as well as the future prognosis. Current conditions of the water supply system may be characterized by so called: failure rate. The parameter may be determined directly by the water system operator and defined as the average number of failures per the unit length of pipe and the time unit. The work presents a theoretical background for the selected mathematical models, that may be applied for the both short-term and mid-term predictions.</p>