Have you taken the handle of to see why the rubber seal is leaking? i have found that usually the seal leaks because it is badly corroded behind the handle, when you try and undo the nuts holding the handle at least 1 usually snaps, then its either a replacement handle or repair the broken screw with a strong glue etc. I would advise removing it so at least you can stop or prevent any corrosion. sorry for the doom and gloom lol