as far as I know, that is an excessive amount of water unless you're specifically trying to do something or are on a cycle.
@MrKleen73 hit the nail on the head. Glassman had started posting a ton of new research on (I think it's called) Hyponutremia? or something like that. Basically the pitfalls of drinking TOO MUCH water. I feel like
@Hyde is the other scientist around here that may have more to offer.
But to answer your question I probably barely hit a gallon a day. probably right at a gallon if you include 2 cups of coffee, a redbull, etc. If my pee is yellowing, I drink more water. I do keep gatorade zero in stock (costco boxes of like 20) and will often grab one in the morning on my way to work, especially if I've been drinking booze.