ALWAYS have your own bottle of water along when traveling regardless of what the standard of service calls for. In business class, Northwest puts onboard enough bottles(small ones) to give each psgr. one after dinner. "Water-walks" are done by f/a's using glasses poured with water from the large bottles. They then go thru and refill as needed with the large bottles. F/a's always run out of bottled water at some point in the flight. Tap water is then used. I've drank it for 20 years and have yet to get sick! People have become too whiney and picky when it comes to H2O! I always find it amusing they refuse to drink tap water, put will drink the coffee and have a glass of orange juice (mixed with TAP WATER)!!! Bottom line...Impress those around you and the crew by bringing your own and showing personal responsiblity when it comes to your thirst!