What is the best thing to do for the water in the body not going out?

Edema vs organ fail: If water in body isn't going out, it's not clear to me whether you're referring to edema eg swelling of legs, or kidney/liver failure or perhaps even heart failure. Or perhaps you have urinary retention due to prolapsed bladder (cystocele). Bottom line, as always, we need to figure out what's going on so that we can make appropriate recommendation. Each of above is treated differently. Go see doc.