Why you don't need to drink 8 cups of water a day

[Warpy]

17. I live in the desert and when the heat hits triple digits I can drink 3 liters a day

without having to march to the bathroom all night. I sweat it out, keeping comfortable and not noticing the sweat because it evaporates as soon as it forms. This climate is just that arid, iced drink glasses remaining dry on the outside.

in winter, it's only a little over a liter unless I want to march all night.

People in northern and western Europe before the introduction of tea and coffee averaged 8 mugs of ale a day. The ale was weak, enough to get them lightly buzzed but not hammered, and its elimination by temperance crusaders caused rural malnutrition, but that's likely another place that "8 glasses of water a day" fiction came from.