I think if you have enough water in your system when you sweat you don't sweat out Dr. Pepper or Coke residue...lol. I drink way too much pop.
I think that when a person has enough water in their system their sweat will be more of a cleansing process instead of a pore clogging process.
I do think dehydration can be a serious issue and that most people get fluids they don't realize. They come in all kinds of clear stuff like Jello, Apple Juice, Clear Broth, Juices without pulp, Honey, Ice Pops, Tea, Coffee, even drinks like Gatorade is a clear liquid. So they do count towards the water/fluid intake at least in some way.
I do think that most people don't realize it's cups of water per day, not glasses. I don't own a single glass that is 8oz. Nearly every glass I have is at least 16oz and most are 20oz. So each 16oz glass holds 2 servings of water. If you drink even one larger glass of water throughout the day then drink tea in a similar way you are getting at least 24 oz. of water per day.
One thing a lot of people don't do too is find what temperature you like your water to be. One friend only likes water at room temperature, another only drinks it the temperature out of the faucet. Me? I like a snow cone for mine. The colder the better. If it's not cold enough to make condensation on the outside it's way too warm for me. One friend only drinks flavored water or she gags. She does not buy any that have sweeteners of any kind in them though, just flavors like lemon or a fruit of some kind.
So to help me drink water I keep cups around from places like 7-11 or McDonalds. I rinse them out so they are clean then put as much ice in them as possible and add the filtered water out of the fridge. Then as I go through the day it is always there. I find that a 44oz cup full of ice will hold about 16 oz. of water. So each time I empty the cup I know I have drank about 2 servings of water. If I keep this cup in the fridge and go get a sip or even chug it very often I will fill it up at least once more during the day.