Exactly! No Water, no Food!
One problem with carrying water in your kit for winter travel is that water tends to freeze (at least in places that have real winter).
I suppose it's OK to do that if you plan to drive from your warm garage, and park in a warm garage at your destination. Or if you plan to bring your travel kit indoors when not driving. Or if your "winter weather" really doesn't go below freezing much.
As I type this it is a balmy -5F (-20C) at my house this morning. If you had parked your vehicle last night in front of my house, this morning your water would be frozen solid as a rock.
Depending on what sort of container you had it in, the container might also have split when it froze. One time after shopping we inadvertently left a couple of bottles of club soda overnight in the SUV. When they burst during the night, the carbonation blew ice chips all over the inside of the vehicle! Quite entertaining, but fortunately not a serious mess to clean up.