Letsbgoofy said:We pack flavored water in zip lock bags, 3 bottles per gallon sized bag. I've never had one break or even leak. We split the bags up between our pieces of luggage so that weight isn't an issue.
I do this all the time, even on international flights. Never had a question from security.
As long as the bag is not overweight, no problem. Although Singapore has an airport(not airline) self imposed weight limit for your carry on, its the only place my carry on ever got weighed. I had to drink a couple pounds of water to get my bag under the limit so I did not have to check it. The plane took off with the same total weight, just two pounds moved under my head not over my head.

I start a trip with 5 or 6 pint bottles in my carry on and more in my checked bag. Yes it weighs some, but its nice to know that the longer your trip is, the lighter your bag gets.

I have a supply of my favorite good tasting spring water that cost me 20 cents each. What is it at the airport, $1.99 to $2.89? Yes the tap water is safe to drink in the US but some places yuck. Although I will refill my bottles if need be from the tap. If my plane is delayed, I am stuck at a hub for an extra 4 hours, I have enough water and snacks to tide me over the wait without having to pay for the overpriced airport junk food, unless I want to. In winter, if there is a possiblity of getting stuck in a hub for a day or two by a snowstorm, I carry enough "provisions" for a day and a half at least in my carry on. That and a good book and while away the hours.
Orlando has drinkable tap water, but many places I'd rather not. It is nice to know that you can arrive at midnight and go straight to your room because you have enough water and snacks in your suitcase to keep you till tomorrow.