Deuterium is a naturally occurring form of hydrogen present in all water on planet Earth. Its concentration varies based on several factors. In the past decade or so people have become increasingly aware of deuterium and desire to know how much is in their water. This book seeks to help to begin to answer that question. The author tested over a dozen waters from around the globe. These included spring, artesian, and municipal water sources. The results are presented in this short ebook and some commentary as to why the deuterium content may be what it is in each water source. This book provides some information on how you can go about getting water samples tested should you want to do that.