Abstract: In this study, the principle of water pinch technology, the optimization of water, steam allocation network have been studied and minimization of freshwater utility and wastewater generation in one of the petroleum refineries of Iran is taken into consideration. In order to research in this field and simplify the relevant calculations, an algorithm was developed and applied for reforming the network. There after amount of freshwater utility in the refinery was reduced from 505 to 340 m3 h-1 and operational costs of refinery (treatment systems and wastewater regeneration) were saved more than 700000 USD annually.