Depends on why you are retaining water. The most basic diuretic, the thiazides, are the most common. You also have carbonic anhydrase inhibitors, combination diuretics, loop diuretics, and potassium sparing. Which diuretic and the dosage depends on physical exam. Does you suffer from obvious edema? High Blood Pressure? Cardiac Problems? Are you truly suffering from high estrogen levels? Get the picture?