How long it takes to drink water and hold urine varies greatly depending on individual circumstances. If you usually eat mainly a light diet and your body is not dehydrated, you can hold urine for half an hour to an hour after drinking water, and you can hold up to a relatively large amount of urine, which can be about 300ml. If you usually drink very little water and your body is more dehydrated, it will take longer to hold urine, and you should hold urine for 2-3 hours before it is possible to hold it up. If you need to hold urine for ultrasound, you should eat a proper light diet the day before and drink more water appropriately, and you can hold urine up quickly in the hospital. It is recommended that you can drink water and various drinks with higher sugar content to hold urine faster.