Hold your water, folks: New evidence suggests that you shouldn't buy bottled water at Starbucks. According to Kathy F., Starbucks uses a state-of-the-art water filtering system for its coffee. In other words, a free cup of water from your friendly, neighborhood Barista will probably taste just as good as the expensive bottled water they sell separately. For my part, I've always wondered why people would pay so much for the fancy water at Starbucks to begin with. What next, an hourly charge for the air we breathe?