I've used a tap water enema/cleanse regularly for over 7 years. I started this regimen shortly after the creation of my j pouch. It enables me to sleep through the night and go for long stretches between bathroom visits. I've had no problems, however I am planning to move out of the country and have been advised by my doctor to use only purified bottled water (and to be sure to avoid bootlegged water-bottled water that is actually tap water). My doctor also mentioned that carbonated water filters out toxins and should therefore be a consideration.