ABSTRACT To improve the operational economy of sewage pumping stations, this paper combines the total volume of the drainage network and sewage pumping station to optimize the effective volume of the pumping station reservoir to reduce operating costs without overflow. Taking a residential area in Ningbo city as the study area, the drainage system was simulated based on Infoworks ICM to obtain the changes of sewage under different volumes of pumping station reservoirs. By combining the daily electricity costs of the pump station, pump start-stop times, and flood depth, the fuzzy optimization method was applied to optimize the effective volume of sewage pumping station reservoirs, selecting the optimal solution to reduce operating costs. A sensitivity analysis of the three factors, pump flow rate, the total population, and drainage network volume, was conducted, and the results showed that under the optimal scenario, the optimal effective volume of the pumping station reservoir increases with the increase in pump flow rate, drainage network volume, and total population. This study can provide theoretical support for the optimization of drainage pumping station reservoir volume as well as economical operation.