2 Drink Water: 3 Over-The-Counter Diuretics: 4 Take Vitamins and Calcium: 5 Prop Your Legs: 6 Wear Compression Stockings: 7 Cold Compresses: 8 Follow a Healthy Diet: Water retention, also known as edema, is a medical condition caused by abnormal retention of large amounts of fluid in the spaces between the body's cells or in the circulatory system.