Keep your kidneys healthy by being “water wise.” This means drinking the right amount of water for you. A common misconception is that everyone should drink eight glasses of water per day, but since everyone is different, daily water needs will vary by person. How much water you need is based on differences in age, climate, exercise intensity, as well as states of pregnancy, breastfeeding, and illness.

About 60-70% of your body weight is made up of water, and every part of your body needs it to function properly. Water helps the kidneys remove wastes from your blood in the form of urine. Water also helps keep your blood vessels open so that blood can travel freely to your kidneys, and deliver essential nutrients to them.

But if you become dehydrated, then it is more difficult for this delivery system to work. Mild dehydration can make you feel tired, and can impair normal bodily functions. Severe dehydration can lead to kidney damage, so it is important to drink enough when you work or exercise very hard, and especially in warm and humid weather.

Eight is great, but not set in stone. There is no hard and fast rule that everyone needs 8 glasses of water a day. This is just a general recommendation based on the fact that we continually lose water from our bodies, and that we need adequate water intake to survive and optimal amounts to thrive. The Institute of Medicine has estimated that men need approximately 13 cups (3 liters) of fluid daily, and that women need approximately 9 cups (2.2 liters) of fluid daily.

Less is more if you have kidney failure (a.k.a. end stage kidney disease). When the kidneys fail, people don’t excrete enough water, if any at all. For those who are receiving dialysis treatment, water must actually be greatly restricted.

It’s possible to drink too much water. Though it is not very common for this to happen in the average person, endurance athletes like marathoners may drink large amounts of water and thereby dilute the sodium level in their blood, resulting in a dangerous condition called hyponatremia.

Your urine can reveal a lot. For the average person, “water wise” means drinking enough water or other healthy fluids, such as unsweetened juice or low fat milk to quench thirst and to keep your urine light yellow or colorless. When your urine is dark yellow, this indicates that you are dehydrated. You should be making about 1.5 liters of urine daily (about 6 cups).

H2O helps prevent kidney stones and UTIs. Kidney stones and urinary tract infections (UTIs) are two common medical conditions that can hurt the kidneys, and for which good hydration is essential. Kidney stones form less easily when there is sufficient water available to prevent stone-forming crystals from sticking together. Water helps dissolve the antibiotics used to treat urinary tract infections, making them more effective. Drinking enough water also helps produce more urine, which helps to flush out infection-causing bacteria.

Beware of pills and procedures. Drinking extra water with certain medications or before and after procedures with contrast dye may help prevent kidney damage. Read medication labels and ask questions before undergoing medical procedures involving contrast dyes. Always consult with your healthcare provider first though, especially if you are on a fluid restriction.