Well Hydrated

Okay, I have been fighting a cold and my wife keeps telling me I do not drink enough water. She says people are supposed to drink half there body weight in ounces. So, if you weigh 200 lbs you should be drinking 100 ounces of water. I keep telling her I drink lots of water at the barn. However, I am discovering that I really am not very hydrated at all. In fact, I think I would classify as the Sahara desert. Now, what really made me wonder was the fact that she is the only one in our little clan who has not gotten the flu/cold this time around. In fact, my wife rarely gets a cold or any other virus that hits the market. So I decided to do a little test with a a 1qt jar. I am suppose to drink, roughly, one gallon of water a day. This morning I drank one quart, at lunch I drank roughly a quart and a half and I drank a few ounces at the barn before milking this evening. So it appears like I still need another quart of water or so. Now she is informing me that it really is not doing as much good as it would if I would drink twelve ounces every hour. I am begining to wonder if she thinks I should drag a water house around with me every where I go. At the rate were going the well be dry and we will be drinking out of the creek. How much water do you drink a day and how does it relate to the number of colds you attract?