Water and the scale

Anybody know how late you can drink water at night and not have it show up on the scale the next morning?  I drink through the day but I know if I drink a 16 oz bottle of water at midnight, wake up at 7:30a, use the restroom and weigh myself, the # will be higher than a few hours later.  Seems like if I don't drink after 8pm, that's not the case.  I'm not talking about ALOT of weight change on the scale.  Maybe .5 - 1 pound but.... I'm just curious how long it takes your kidneys to process the excess fluid and expell it. Thanks in advance. Mick

My weight literally varies by 8 pounds daily and I'm sure it's water weight.  My weight in the morning is usually the highest of the day with the evenings (after all the exercise) being the lowest.  

I also try to drink at least 1 gallon of water (128 ounces) a day not including coffee and water in my protein shots.   Not sure how quickly it's supposed to go through your body because it seems like I have to pee every 15 minutes.  :)