Patients with Diabetes Insipidus (DI) experience a continuing thirst that the patient tries to satisfy by drinking fluids.  This is called polydypsia.  Some patients always seem to be drinking fluids - as much as a full glass every 10 to 20 minutes.  If deprived of fluids, some children have been known to try and quench their thirst by drinking directly from faucets, pet's dishes, and other sources of liquid from around or inside the home.

In addition to excessive drinking of fluid, patients experience excessive urination, known as, polyuria.  It seems as if the water simply passes through the body.  The patient can become very dry with loss of weight, dry mouth and fatigue.  This is due to lack of the hormone from the pituitary that concentrates the urine.