In 2008, the average American drank about 30 gallons (133.6 liters) of bottled water [source: Gleick]. While a gallon of tap water costs about a penny, the same amount of bottled water costs roughly $8 [source: Thau]. This means the average American spends about $320 a year on bottled water.
But why? The water most likely isn't cleaner -- a 2008 study by the Environmental Working Group found 38 contaminants in 10 brands of bottled water [source: Environmental Working Group]. There are serious environmental costs, as well -- for example, a thousand plastic bottles are thrown away every second of every day in the United States [source: Gleick].
Consider ditching the bottles and purchasing a water filtration system. Brita, PUR and other companies produce special faucets, water pitchers, dispensers and hand-held bottles specially outfitted to filter out chlorine, lead and other impurities from drinking water. These systems cost between $15 and $50, in addition to the cost of filters -- Brita filters, for example, cost about $8 and must be replaced after filtering 40 gallons of water [source: Brita]. That means that if you drink eight 8-ounce (0.24-liter) glasses a day for a total of 183 gallons (692.7 liters) of filtered water each year, you'd need to change the filter five times and spend less than $100. That's six times the average consumption of bottled water for about a third of the cost.