A person who is
urinating excessively has compounds in the bodily fluid that causes this nonstop release of water. Also, if there is any disease in the kidney, there is loss of control over the fluid release. The pituitary gland in the brain controls the urine flow from the kidneys - but polyuria destroys this ability to control the urinary tendencies. My brother once joked that if anyone among us suffers from polyuria, there should always be a constant supply of tampon and diapers in the backpack.