I'm drinking close to that, 3 liters, not 3.8, and I balance my electrolytes with 500ml coconut water a day and 1/8 tsp salt in 2 of those liters with just a little flavoring added. Do you think the sugar substitues dehydrate as much as table sugar? So far, it's helped me regulate my body temperature better and I'm finally sweating a little.
RE: What happens when you drink a gallon of water every day?