Besides, the sense of safety offered by bottled water is a mirage. It turns out that breathing, not drinking, constitutes our main route of exposure to volatile pollutants in tap water, such as solvents, pesticides, and byproducts of water chlorination. As soon as the toilet is flushed or the faucet turned on-or the bathtub, the shower, the humidifier, the washing machine-these contaminants leave the water and enter the air. A recent study shows that the most efficient way of exposing yourself to chemical contaminants in tap water is to turn on a dishwasher.