How water becomes urine
If you choose to swallow, the water runs down your throat, past the epiglottis, which is closed so that the water won't end up in your lungs, and on down through the oesophagus into your stomach.
The stomach
In your stomach, the water is needed to assist in the processing and digestion of food. So far, your body has not absorbed any water. The only thing that has happened is that your thirst was probably quenched and the amount of saliva has increased.
The water and the food are mixed into a dough and kneaded out into your body's intestines.
The small intestine
In the small intestine, your body starts to absorb fluid, as well as vitamins and other nutrients from the dough. These nutrients are absorbed by the blood and transported to all your body's cells.
In the small intestine, the food is so finely ground and kneaded that it no longer is firm, but rather looks like batter. After a while, this batter leaves the small intestine and continues on to the large intestine.
The large intestine
The large intestine's task is to absorb as much liquid as possible from the thin batter, so that your body can make use of this liquid and achieve a proper balance of body fluids. This is important, as 60% of your body is water.
The kidneys and the bladder
The liquid you drink is absorbed by the blood vessels in your large intestine and transported by the blood to your kidneys. In your kidneys, the blood is purified and the water is converted into urine that flows through the ureters to your bladder. When your bladder contains about 200-400 mls of urine, you usually go to the toilet to empty your bladder.