I'll just remark that for water, I do want to drink a pure chemical, possibly with a little bit of minerals in, if it can't be helped.
Total dissolved solids must be under 500mg/L in US drinking water supplies, and the highly regarded NYC water system delivers water with less than 50mg/L of total dissolved solids. Most of that is sodium chloride, calcium chloride and magnesium sulfate, classic tasty salts... all of which are readily available in foods.
See http://www.nyc.gov/html/dep/pdf/wsstate13.pdf for the 2013 water quality report; see table 1.
If you got distilled water instead, you'd notice the taste, but there wouldn't be a health problem.
I believe there is an episode on National Geographic channel from the show "Going Deep With David Rees" where he visits a lab that makes Pure H20. He is only allowed to sip it. The episode was about creating ice without impurities. (it was found that pure H2O is not necessary to creating perfect ice, not is it made for human consumption.)
Only if you don't eat anything at all with it.