I think you are confusing two different things.
There is a certain amount of water tied up with your glycogen. As you loose glycogen, you will drop alot of water weight. Its about 1:3 ratio. So with about 300-500 grams of glycogen in your liver, you potentially loose about 1.5kg of water weight. This does not include the glycogen in your muscles.
When you are dry fasting, at some point when your body is nearing dehydration due to not drinking water, your body starts to metabolises fat to produce metabolic water. This is about 100gram water to 100grams fat iirc.
Your body will produce enough water to keep your organs functioning. I believe this will depend on your height, your weight etc