Good point. I recall reading that the British habit of drinking tea arose because boiling the water to prepare the tea killed the bacteria typically found in unheated sources of water. According to that article, the British didn’t drink water like we do - they drank boiled tea, all the while not realizing why tea was less likely to make them sick then still water. I wonder how that theory matches up with the possible existence of tea leaves that ‘fell in water’. How is it that the Chinese could enjoy ‘infused’ (non heated) tea with fewer bacterial concerns, apparently, than the British?
Tea itself has antibiotic qualities.
Until fairly recently most city water was unsafe or chancy. That's why people drank so much coffee and tea, or, more to my liking, so much beer, wine and spirits.