If he is an athlete, yes. Otherwise, consult Endocrinologist or Functional Medicine doctor.

Peeing soon after drinking water could result from neural reflex - similar to a feel to pee at hand washing for some people, particularly in some elderly. To answer your question, one has to review and relate a lot of medical information. To build up the foundation for comprehensive medical counseling, please take the time to review the pages on http://www.formefirst.com/onBPH-LUTS-VoidingTrouble.html. Thereby, you would be able to have a meaningful evaluation and adequate medical care. Best wishes for health, happiness, and medical care.

Some individuals may void more frequently than others. However, your son may need to be evaluated to make sure he's not a dysfunctional voider and is emptying his bladder appropriately.

It normally takes anything between 5–120 minutes for the ingested water to get into the urinary bladder; however it depends on the state of hydration, secretion of anti-diuretic hormone (ADH), external temperature and of course your kidneys- they should be functioning normally. It is neither normal nor abnormal to urinate after drinking water.

See urologist to check for good bladder emptying