We’ve had quite a few comments lately along the lines of wanting fluoride removed so that we are drinking ‘pure’ water. However, the cessation of fluoridation by itself won’t achieve that.
Hamilton’s water hasn’t had fluoride added since supplies ran out after the HCC tribunal’s decision. However, we’re still getting 0.3ppm F- in our water because that’s the level found in the Waikato river. There’s also chlorine, some calcium (more in areas with ‘hard’ water) & trace levels of various other elements & compounds (Dr Ken Perrott written about this, plus there’s a list giving maximum allowable concentrations in the DWSNZ document).
Even rain water won’t be ‘pure’ in this sense as it will collect material from the atmosphere as it falls (& in some circumstances may contribute to increased contaminant load). When there are algal blooms in the water, as happened a couple of summers ago, then this may result in odour issues (which indicates some form of contaminant has made it through the treatment plant).
In fact, the Drinking Water Standards for NZ make it clear that drinking water is not ‘pure’: “The DWSNZ define the maximum concentrations of chemicals of health significance (MAVs) in water that, based on current knowledge, constitute no significant risk to the health of a person who consumes 2 L of that water a day over their lifetime (usually taken as 70 years).”

Source:
http://www.health.govt.nz/publication/drinking-water-standards-new-zealand-2005-revised-2008