Micropollutants contaminate the water worldwide. Among them are steroid hormones that cannot be eliminated efficiently by conventional processes. Researchers of Karlsruhe Institute of Technology (KIT) have now developed an innovative filtration system that combines a polymer membrane with activated carbon. As the size of the carbon particles is very small, it is possible to reach the reference value of 1 nanogram estradiol—the physiologically most effective estrogen—per liter drinking water proposed by the European Commission. The improved method is reported in Water Research.