Every day, your kidneys filter about 30 gallons of blood to remove about half a gallon of extra water (fluid) and waste products. This waste and extra water make up your urine (pee). The waste comes from the food you eat and the use of your muscles. Your urine travels to your bladder through the ureters, tubes that connect your kidney to your bladder. Your bladder stores the urine until you are ready to urinate (pee). When you urinate, urine leaves your body through your urethra.

Your kidneys also do many other jobs, such as help:

When your kidneys don’t work the way they should, they allow waste and water to flow back into your blood stream instead of sending them out with your urine. This causes waste and water to build up in your body, which can cause problems with your heart, lungs, blood, and bones.