well if it is very much it is probably best to talk to your GP about it... and have your heart excamined, water retension can come from a number of reasons, also allergy , or mal-nutrition , if the potassium ><sodium is out of balance and in that case it is very important to do excactly what doctor says, or if ones heart has become weak it can also lead to water retension in ones legs
if all this is ruled out then there is a folk-remedy that one can try : 1/2 a liter redwine mixed with 150 gram grated horseradish, leave it in fridge in a glass jar with lid on, then eat two spoonfuls every morning ... no more than that .. and it helps many with retension, dont know what the mix creates but it helps many... but this is only to try after having a doctor excamine you and discuss the problem with him/her