The model developed in this study and described in this article has the ability to characterize water nutrient status, as well as to predict behavior of indigenous bacteria. The ability to predict bacterial population dynamics with respect to nutrients is beneficial for water treatment optimization and as a component of a dynamic water-quality model for distribution systems. Currently, there are no cost-effective methods available to the water industry to characterize treated water quality. This study has addressed this need by the development of a model. The drinking water industry can adopt this model to characterize water quality, which in turn will indicate the performance of treatment facilities and whether any upgrades are needed.