system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How is water 'purified' naturally (where it is safe to drink)?
gpt
Well, mainly the water cycle. Evaporating water then it falling back to the ground esentilally gets rid of any impurities. The rivers through which the water flows generally have been washed out by previous water, which pretty much cleans the actual riverbed of most impurities that may be loose, therefore it becomes mostly clean. Of course it is not completely clean, some impurities are still there, but they are few and far, assuming no one has dumped any shit upstream. And as the saying goes, still water is bad water, but moving water is generally safe. Really, humans are the main reason many streams these days are no longer drinkable.