Without enough ADH a person cannot control the amount of urine and he or she loses too much water from the body. Therefore dehydrated. U become thirsty,dry mouth and yes stil make large amounts of urine. If the child cannot get enough fluid to replace what has been lost in the urine, this leads to dehydration and a very high level of sodium in the body. Test like water deprivation test needs to be done. This involves a test lasting up to 8 hours done in hospital .Nil water througout test.