Actually if you drink too much water in a short period of time it can kill you. There was a case on the news where I live a while ago. Some teens had a contest to see who could drink the most water without going to the potty. The young girl ended up dying. Your kidneys can only filter so much liquid per hour at a time. If you drink too much at once it causes water toxicity. I read it does not matter if you drink much over a long time. Its if you drink a lot too quickly.