How much water you need depends entirely on an individual’s lifestyle, activity levels, eating habits, and even surrounding climate. The best way to figure out what you need is to pay attention to your body’s many signals.
Dehydration actually sets in before you start feeling thirsty, and is often indicated by, oddly enough, feeling slightly hungry. If you find yourself feeling like a snack, try having a glass of water first, and see what happens.
For people who struggle in the mornings, having a couple of glasses of water right when you wake up will help boost your blood pressure to normal levels. It will also help clean out your system and get your metabolism started early.
Not staying hydrated can lead to negative health effects described in this helpful infographic: