I have a cistern that is repeatedly overflowing out down the wall into the garden (useful for watering plants but its upsetting the neighbours with the limescale deposits it leaves on their windows!) My husband changed the ball valve on it last year and set the new plastic one to the lowest setting it has, it stopped leaking for about a month but now its started getting a bit more enthusiastic about sprinkling everywhere. Its definitely the cold water tank that leaks. It seems to take forever to fill up as the valve dribbles really slowly into the tank, so when we want the drip to stop for half an hour or so we flush a toilet in the house. Should it take so long to fill before it reaches the shut off point (or apparent lack of, in our case), and how can we get it to stop at the shut off point and stop it leaking? Any ideas will be gratefully appreciated!