I’m always thirsty when I fast so once I drank a huge amount of water before fasting. I cannot tell you what cramps I got from that. Too much water is not healthy and depending on the amount can be dangerous (which I learnt after that incident).
It’s important to stagger fluid consumption throughout the day not drink it all at once. It’s also a good idea to eat fruits with high water content like watermelon.
philosopher-you are right-its a good idea to drink throughout the day water, don’t cram it in right before the fast, hopefully you won’t get cramps from that.