wendy, I assume the people who pack water don't have a rental car, and don't want to spend $$ for a cab or something to go to a store to buy a case of water. Also, I know for myself, I would prefer not to spend my vacation time shopping, so I understand the desire to just bring things from home, rather than spend the time shopping. (I don't bring water though, we get it from the lounge for free or buy it one bottle at a time

)
tanmar, are you absolutely sure about the baggage allowance on your flight? 44 pounds is ridiculously low! So, that means you are only allowed ONE bag that weighs 44 lbs? That is crazy. I would double check that--and also ask what it costs to go over that amount. What airline is that?! Crazy.
BTW, this thread should be moved to the Transportation board, you might get more info there from people who have done this and flown on that airline.