The problem with antibiotics in the water supply seems to be the breeding of antibiotic resistant strains of bacteria and viruses, etc. There is no mention of any direct problem with drinking water containing ABs, although if there are ABs in the river water, what else is therein?

I certainly would not want to obtain drinking water from the Thames, or any other river in the lower. settled portions of the watershed. Give me a nice spring well upstream, the farther, the better. Then boiling is likely to produce potable water.