Chlorine and fluoride are both bad but fluoride is particularly problematic because it is added to water for the SUPPOSED dental benefits. That's mass medication, without consent.
Water has to be purified somehow though...
There was a poster here a while back that pointed out the fact that not many are subject to infectious disease due to contaminated water these days... point taken.
Do a search on water purification with iodine. There's a company in Australia involved in that, I think.