Pelvic ultrasonography (US) is a simple and non-invasive radiologic test to evaluate the pelvic organs. It requires a full bladder for better visualization. Our case is a 14-year-old female with diabetes insipidus (DI) who admitted to the pediatric emergency service with the complaints of seizure and agitation after drinking 4 liters of water in one hour for a pelvic US examination due to work-up for delayed puberty. Her biochemical and clinical evaluation revealed water intoxication (WI). To our knowledge, this is the first WI case developed in a patient with DI. Here, we discuss the underlying factors leading to this complication and recommended an approach to obtain a better sonographic image without necessitating oral water intake to fill the urinary bladder.