It seems obvious, but sometimes we don't event notice under-hydration. You may be surprised at some of the symptoms! Here's an interesting read by Matt Duczeminski.
There’s not much in this world more refreshing than a tall, ice-cold glass of water. I don’t think there’s anyone alive that can deny that sometimes, a simple glass of water can be more satisfying than a cup of coffee or a can of soda. Despite this, too many of us don’t drink enough water on a daily basis. By depriving ourselves of the world’s most natural resource, we are continuously damaging our bodies. If you experience any of the following, you can improve your situation by starting with a glass of H2O. Read about the 14 signs you may have telling you to drink more