<prompt> Answer this question truthfullyHow does someone with ureteropelvic junction obstruction typically maintain normal urinary output despite the obstruction?  <response>: <reason> How does someone with ureteropelvic junction obstruction typically maintain normal urinary output despite the obstruction? The narrow area can still handle normal urinary flow, and only if there is a large diuresis does it become unable to handle the increased flow, leading to symptoms. 