I like carbonated water as well, but don't drink it everyday. Here was what I found:
"What we do know is that [gastrointestinal] doctors are aware that carbonated beverages like sodas can exacerbate a condition known as GERD (gastroesophageal reflux disease), which has been linked to esophageal cancer."
http://www.buzzle.com/.../...flux-disease.html"The lower esophageal sphincter (LES) is a muscular valve at the bottom of the esophagus which allows ingested material to move down into the stomach. It is designed to close and keep this material from coming back up. Most people who experience Gerd do so because the LES becomes relaxed and malfunctions, allowing acid to reflux. Where the stomach has an acid proof lining the esophagus does not and is easily damaged by stomach acid. ... Carbonated beverages relax the LES"
Note that the sugar content is irrelevant: carbonated water beverages containing no sweetener of any kind will still cause your LES to relax.