I agree with sentinel there, if you really want some clean water I really recommend you get some water filtration system.
My brother gave me a Watts
filtration doohickey, I think it's WG-1 digi or something like that, and it is the bomb!
It isn't as beastly as the better systems but you really can tell the difference, it takes shit out of water and what you are left with is nothing but wet
Tap water in Finland is pretty damn clean, but even so, the area where I live the water mains were built in the 40's and I don't trust they are clean at all even if the water is at the source. Though, mainly I use it to bottle water for couple of days and making some coffee.
Invest in a beast of a system and you can take everything but the CO2
out of the water, guaranteed you won't have anything else in it, though you won't have any minerals or anything like that and would have to tap it like the astronauts do with sodium and what ever.