This paper presents a novel framework for the deterioration modeling in conjunction with quantifying the water network's failure index. It involves developing a method and an intelligent model using Monte Carlo Simulation to estimate the deterioration indices (DIs) of watermains through intricate iterative simulations. The developed method is implemented on the water system of the City of El Pedregal in Peru. The efficacy of this framework has been verified against the multiple linear regression (MLR) method and proved to be sound. The developed framework provides insights for infrastructure managers in the aspects of, when to intervene, what to maintain, replace, or rehabilitate.