Question: how much water to drink to improve kidney function?
Answer: 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.