One of the tried, tested and really proven methods that are employed to control the water that is fed into a WC cistern and water storage vessels is by using the ball or float valves. Willesden Plumbers can replace ball valves. Simply put, the float will sit on the waters surface in a cistern or tank and is connected to an arm that opens and closes a valve and in doing so controls the inlet of water. As the water level in the cistern lowers, the arm lowers also, and opens the inlet valve and allows water to enter the cistern, now, as the water level is raised, so does the ball or float, which in turn moves its connected arm to close off the water supply as it reaches its pre determined level. These, ball valves are not, as with most things not failsafe. In fact if they fail they can release a huge amount of water into a relatively small tank or cistern. To cope with this, every tank or cistern as an overflow pipe. Although these appliances are known as ball valves, the ball part is taliking about the shape of the float, however this float could be any shape, for example, the thinner cisterns having little space inside can use narrow, non-spherical floats. A Willesden Plumber can replace and refit a faulty ball or float valve. These floats are normally just screwed to the end of the arm, perhaps with a locknut on the arm. The metal floats can sometimes leak after years of constant use (not with plastic floats). You should visually check the condition of your float valves annually. It only takes two minutes and can be part of a general plumbing for the house. As a rule if you decide to replace the ball/float valve, check the condition of the overflow pipe and change this at the same time if needed. Replacement is easy and involves removing the old float and attaching a new one to the end of the arm, always fit the same style and size of float as originally fitted.