Bottled water sales are booming -- over 4 billion gallons this year alone. Home water filters and purification systems are setting record sales, too, as many look to trade plain old regular tap water and trips to the market for bottled water for the convenience of filtering and purifying watere. While there are many filter types to choose from, only one is considered best -- reverse osmosis. It is the cr?me de la cr?me, and the only one used by NASA for astronauts. While others simply pass water through a filter to remove some chemicals and minerals, reverse osmosis lets only tiny water molecules pass through its high-tech membrane while all impurities including salt and lead go down the drain. All that's left is the best, purest drinking water you'll ever taste. And that's the On The House tip for today.