You hear it over and over again: “Drink at least eight glasses of water a day.” But how much water do you really need? And how much is too much? Water is about 50% to 75% of your total body weight and is required for survival. But the amount of water required depends on multiple factors: A person’s overall health, physical activity level, diet, medical conditions, and the climate where they live all influence your water necessity. Maintaining good hydration helps balance nutrients, removes waste from your body, and decreases the risk of developing associated health conditions like kidney stones.