Water has zero calories, and its good for your body. And the interesting thing is, if you drink plenty of water (at least 64 fluid ounces a day), then your body will retain less water. This means you will lose weight, and that's a good thing. So do it.
You also burn calories by raising the temperature of the water to your body temperature. If you drink the recommended 64 ounces of water every day, and you make it ICE COLD, then you will burn an extra 70 calories a day (compared to if the water was already body temperature). If you do this for 50 days, you will lose 1 pound. (Probably two months because you won't do it every day.) You aren't gonna lose much weight doing this, but every little bit helps right?
- HowStuffWorks.com - "Does drinking ice water burn calories?"
From Harvard Fiber page: Wondering how much water or other beverages you should drink a day? The Institute of Medicine's Food and Nutrition Board gives the following general recommendations for water consumption: Women generally need to consume 91 ounces of water each day from beverages and foods, while men generally need to consume 125 ounces each day. People typically obtain about 80 percent of their water from beverages (including beverages that contain caffeine) and 20 percent of their water from foods. So for women, that translates into drinking 9 8-oz. glasses of water or other beverages each day and obtaining another 18 ounces of water from foods; for men, that translates into drinking roughly 12 8-oz. glasses of water or other beverages each day, and obtaining another 25 ounces of water from foods.