This paper presents a mathematical programming model for the optimal synthesis and retrofitting of water networks based on the properties of the streams that impact the processing in the plant and the environment. One important feature of the proposed approach is that it accounts for changes in the operation through a time horizon with growing demands. The optimization formulation considers changes in the demands and accounts for time-based variations in the flow rates required for the process sinks and constraints for properties in the process sinks and in the environment. Furthermore, the proposed model allows the installation of different units and the retrofitting of the water network over the considered time horizon. The objective function minimizes the total cost associated with the entire life of the project while accounting for the time value of money and the specific demands for the process and the environment that change through the life of the project. Two case studies are solved to show the applicability of the proposed approach.