A gollon of water weighs 8.34#'s, and I don't know anyone that carrys a gallon of water. As has been suggested, if there's a water source in your area, the better option is to get a filtered water bottle, or a filter pump and carry a smaller amount of water and refill as needed. I rarely drink but maybe a 1/2 gallon/day, but everyone is different, some may need more, expecially flat landers coming into the high country.
I can go into the high country on a 3 day bivy hunt and not carry 10#'s of water and food. So a guy should be able to do a day hunt with a lot less than 10#s of water and food combined.