So, yeah, it's definitely important to make sure you're getting enough water. But the exact amount of water that we each lose and need to replenish isn't as simple to figure out. As it turns out, that daily requirement is going to be pretty different for everyone depending on all sorts of factors. For instance, the amount of water you need to drink every day will go up if you regularly work out, live in a warm or humid city, have been dealing with a cold, or are pregnant or nursing, says the Mayo Clinic