Sure. Also you hydrate your whole body so all the processes that need water have water. And then you can last some time without water(without perceived negative effect), but I do prefer to always have water around.
half a liter and I'm going to the WC in 15 minutes. But then I weigh little. If you drink 2 liters and don't need to check the toilette for several hours, I'd visit a doctor.
Whats wrong with going to the toilet? Thats part of the body process to flush out unwanted substances. So if you drink enough, you flush out enough - and then you do not need so much water anymore. So you can drink lots of water and then not needing more water. So the storage of water you have when you are hydrated, lasts some time. That was my point.
But you are correct, that when you drink more and more, despite your body being already hydrated - then it pretty much comes out like it is soon after.
": Our findings agree with the long held notion that each gram of glycogen is stored in human muscle with at least 3 g of water. Higher ratios are possible (e.g., during REHFULL) likely due to water storage not bound to glycogen. "
If you want to store extra water for short periods drink/eat carbs
starch can also stimulate the uptake of water in your small intestine. Oral Rehydration Salts combine some dextrose and salts to mix into a liter of water. When properly mixed the salts are in a homeostatic quantity and won’t affect the salt balance of existing tissue. So you can drink them to recover from severe dehydration without risking hyponatremia.
You need to replace the salts in your body if you're drinking large amounts of water. Sodium and potassium are what signal muscles to fire. If you drink excessive amounts of water without supplementing electrolytes, you end up with water toxicity, which can be fatal.
Sports drinks are generally water with sodium chloride and potassium chloride added, often with sugar as well. Trust me, if you're sweating a lot and drinking a lot of water, you need a source of the appropriate salts.