How long before a match can I drink water and still lose it before my match?

I understand that water does not magically vanish, I appreciate the clarification tho. I meant, if I drank 20 ounces of water now, how long would it be until I peed that out?

Usually 30 minutes or so. I think spitting is the best way to lose water weight. You don't waste any energy doing it. Use gum.

if you are dehydrated it might not come out of your body. best way to do it is sweat it out. especially if you've been cutting weight already then take in water, more than likely it will stay in your system for longer.