Drinking too much water will hurt you IF you drink it too fast. In actual fact it’s not generally how much water you drink, but how quickly you drink it!
Recently a woman died during a radio contest from consuming too many bottles of water in a very short time frame. Her brain and organs swelled so badly that she could not recover. If she had drunk that same amount of water over the course of a whole day rather than within just one hour, she would still be alive today.