It's not water, it's probably mucus. It's common to pass small amounts of mucus with bowel movements, but if it becomes frequent and in larger quantities, you should see a doctor. I actually have been having the same problem recently. I went to the doctor, he said I have Colitis (inflammation of the bowels) and gave me some pills. Didn't help the problem. I'm still trying to figure out why this is happening. It has also been accompanied by constant pressure on the rectum aka feeling like I have to go poo all the time. Anyway, that's why I'm on this site! So yeah, look up mucus in the stool. Could be Colitis, could be Chrone's Disease. Any other symptoms? Has this continued to happen?