The continuing growth of the world's population and ongoing climate change lead to many problems related to the increased demand for water. The answer to this problem could be responsible and sustainable water reuse. Therefore, the EU has introduced a water management policy based on, among others: the Water Framework Directive (WFD, Directive, 2000/60/EC, 2000), the Blueprint for Safeguarding European Water (European Commission, 2012), or the Circular Economy (CE, 2015 updated in 2020). Taking into account this fact and the fact that in the future electric cars will completely replace combustion cars on the market, an attempt was made to purify post-fire water in the presented work. In case of fire in such cars, due to their construction, they are first extinguished in a water jet and then placed in special containers filled with water. All kinds of substances released from the burnt car get into that container. Due to the tightness of the container, it is possible to purify this water. The proposed polymer membrane cascade in the presented manuscript consisted of gravity filtration, microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. This allowed for a significant reduction in contaminants in the water. The chemical oxygen demand was reduced by more than 75% and the 5-day biochemical oxygen demand by more than 90%. The concentration of lithium, cadmium and nickel in the container water was, respectively, 142.2 mg/L, 0.015 mg/L and 1.63 mg/L. The use of cascade filtration reduced the concentration of these ions to the level of 0.799 mg/L of lithium, 0.009 mg/L of cadmium and 0.012 mg/L of nickel.