>>8609282it depends on the fluoride concentration of your drinking water but typically you never exceed that much fluoride in a day to pose any possible risk, regardless of the country you live in
to put it into perspective: there was a girl in leafland who died after drinking something like 7 litres of water (she did not live in an area where fluoride in water actively reduced), but died not from fluoride but from overhydration/water poisoning. its unlikely youll ever drink enough fluoride ever hurt yourself from that; you sooner die from water poisoning this way than fluoride poisoning so its essentially never something to worry about from drinking water unless you go ridiculously overboard. i drink about 2 - 3 litres of water per day and am at nearly 0 risk of fluoride poisoning or experiencing any risks of damage due to fluoride
on this note, heres a fun fact that has come up the last few times ive talked about fluoride in water on 4chan: apparently its a common thought that its harder to swim/you sink faster in heavy water than in regular water, but actually the opposite is true. you swim much easier and with much less effort in pure heavy water compared to regular ass water, even salt water