First, it is an interesting topic regarding water therapy and how they are being applied.
May I know the site for this? and Is this CLINICAL study established?
Hypertension? Esp. with complicating Heart Condition such as CHF (Chronic Heart Failure) => Drinking too much water is a NO NO. Or if you want to die with Pulmonary edema(Leaking fluids in the lungs due to excessive high pressure of the capillaries in the lungs) then go for it.
CRF(Chronic / even acute renal failure) => The water you take in doesnt go out. So if you keep drinking water, youd really be in trouble.
Unless you are really healthy, drinking plenty of water is GREAT! it cleanses you and aids in removal of metabolic waste products.
SO its best to have a doctor evaluate youre "PROPOSED" treatment plan before undergoing this water therapy esp if you have existing medical condition.