In this research, we quantify combined point-source inputs of nutrients, microplastics, a chemical (triclosan) and a pathogen (Cryptosporidium) to 10,226 rivers in 2010, 2050 and 2100, and show how pollutants are related. In the future, 80% of the global population could be living in urbanized areas where waters are polluted with multiple pollutants. We could formulate scenarios where future water pollution from growing cities is avoided by advanced waste water treatment in many world regions, but not in Africa.