Synthetic fiber fragments from household washing are one of many types of microplastics that enter the environment. The potential and costs of fiber retention, using filters, were modeled for Germany. The high costs indicate that synergistic measures for the simultaneous retention of different types of microplastics from other sectors, such as road traffic, should not be overlooked in terms of cost-effectiveness. Around 500 tons of microplastics enter the wastewater from washing machines every year, of which, around 91 % is removed by conventional wastewater treatment. The separation costs amount to approximately EUR 2.2 million per ton. The widespread use of filters already available on the market in households could increase the proportion removed to 96 %. The costs for the additional separation amount to approximately 114 million EUR per ton. The use of filters would increase the costs for household washing by approximately 37 %.A comparison with the separation of tire wear reveals synergy potential. Around 20,000 tonnes of microplastics from tire wear are subjected to conventional wastewater treatment in the same way as the fibrous microplastics from the washing process. One starting point, for example, is that both types of microplastics can bypass the wastewater treatment plants and enter the environment as so-called overflow if the wastewater network is overloaded. The potential to reduce the input of microplastics, by reducing the release through overflows, far exceeds the savings potential of individual measures such as the installation of filters in households.