Comment by impossiblefork

Generally not, but we choose where we take our from water from.

If there's too much fluoride in the rock water we take soil or surface water instead, for example. If there's too much fluoride in the water we do not supply it to people's taps, but this is for values like 4 mg/L.

So we mostly don't take any measures. In Stockholm it's apparently less than 0.2 mg/L though.