Batmanghelidj has been discredited. See http://www.quackwatch.com/11Ind/batman.html and http://www.snopes.com/medical/myths/8glasses.asp. He discovered his miracle "cure" when he was on death row in Iran (for being on the wrong side in the Islamic revolution) and managed to survive because as a doctor he could treat other prisoners. Funny how the threat of execution can make you discover previously unknown properties in everyday items, and the only "medicine" he had access to was water.

He didn't practice medicine after being released from prison in 1982 and he didn't publish any research apart from a couple of short papers that were just rehashing what he did in prison and can be summarized as "I think...". If he had any evidence that water can cure ulcers (or anything else for that matter) he took it to the grave with him. Like most of his sort, what he was really promoting was placebo. It doesn't actually do anything but it makes you feel better because you think it will. At least the "water cure" won't do you any harm.

Drinking enough water is good for you, but watch out for quacks trying to read more into it than is actually there. It's also worth remembering that food contains water and that the small dehydration effect from tea and coffee is vastly outweighed by the water intake that you get from them. The only drinks that do cause dehydration are alcoholic ones. The idea that you must drink 8 glasses a day and that it must be specifically water is an urban myth.