Natural systems are a cost-effective way to clean wastewater from small communities. This paper aims to use an optimization technique to minimize the volume of concrete needed to construct a facultative pond provided within a series of three ponds. A nonlinear constrained optimization model was written and then solved using one of the Add-Ins of MS office. The add-in used was Excel Solver, and the algorithm was generalized reduced gradient (GRG). Be-fore applying the optimization model, wastewater stabilization ponds (WSPs) were designed using various configurations and arrangements. The best possible configuration that gave min-imum area and hydraulic detention time was selected for the study area. Afterward, the optimi-zation model was applied that further reduced the area by 11.46%, hydraulic detention time by 11.47%, and concrete volume by 6.94% compared to the traditional approach. In both methods, effluents satisfy the Turkish class-B standards for irrigation. It is recommended that a small-scale application of the model be made to compare the results before applying it on a large scale.