Hydration is really important, and the purity of what you're drinking is, too. Unfortunately, the quality of the tap water in most cities in the USA is extremely poor. I just found out the results of my city's water: http://www.ewg.org/tap-water/whatsinyourwater/CA/Pasadena-City-Water-Dept/1910124/
Pretty disturbing, huh? You can check your city on the same site and see its score.
Bottled water is no guarantee you're getting anything purer. Many times, all you're getting is tap water in a bottle-- same as you'd get at home, only more expensive and with a fancy label. Check what the NRDC has to say about this: http://www.nrdc.org/water/drinking/bw/exesum.asp
I highly recommend getting a good filter for your home water. Here is a good comparison of different kinds of filters: http://heartspring.net/water_filters_guide.html If your tap water is full of contaminants, you owe it to yourself to drink (and wash your food in!) the purest water you can get.
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