Green and grey stormwater management infrastructures, such as the filter, swale and infiltration trench (FST), can be used to prevent flooding events. The aim of this paper was to determine the environmental and economic impacts of a pilot FST that was built in São Carlos (Brazil) using Life Cycle Assessment (LCA) and Life Cycle Costing (LCC). As a result, the components with the greatest contributions to the total impacts of the FST were the infiltration trench and the grass cover. The system has a carbon footprint of 0.13 kg CO2 eq./m3 of infiltrated stormwater and an eco-efficiency ratio of 0.35 kg CO2 eq./USD. Moreover, the FST prevented up to 95% of the runoff in the area. Compared to a grey infrastructure, this system is a good solution with respect to PVC stormwater pipes, which require a long pipe length (1070 m) and have a shorter lifespan. In contrast, concrete pipes are a better solution, and their impacts are similar to those of the FST. Finally, a sensitivity analysis was conducted to assess the changes in the impacts with the varying lifespan of the system components. Thus, the proper management of the FST can reduce the economic and environmental impacts of the system by increasing its durability.