I read some articles about drinking plain water. Yeah, water is essential. However, drinking too much has a side-effect. You may feel bloated because too much water will slow down your electrolite flow in the blood stream. That's why recommended amount of water is 2 liters per day (that's 250ml times 8, cups of water a day). Of course to stay hydrated you gonna need to drink water, but not too much, I think.