To stay properly hydrated you should have a goal of drinking 8 - 10 ounces of water every hour. A drinking fountain can give you this much water in about 10 seconds.

You should drink 10 ounces of water before going to bed and as soon as you wake up since you miss time to drink while you are asleep.

It is important that you drink water every hour since you can't "catch up" by drinking more than 10 ounces of water. Your body won't be able to absorb that much water at one time.