Ball valves or water inlet valves are often found in many houses, there could be one in the toilet cistern or there could be one or two in the header tanks for the central heating system. Modern toilets use more compact filling valves so that the size of the cistern can be reduced.

If your toilet or cistern is constantly filling then the chances are that either the ball valve needs adjusting or the ball valve washer needs replacing. In most cases you will have water running out of the overflow pipe, although some toilets now use internal overflows. This is a side entry ball float valve, these are not seen in toilets much now, but are often found in central heating header tanks etc.-

The first thing we need to do is to isolate the water supply to the Valve. This can be done by turning the isolating valve beneath the valve (if there is one) or you will have to isolate the water supply to the whole house as described here-

Isolating the water supply

You will notice that there is a split pin that is holding the ball valve arm into the body. We need to remove this pin and so it needs bending straight using a pair of pliers or mole grips.

Lift the arm clear of the ball valve.

There is now a nylon cylindrical shaped fitting inside of the ball valve, this can be removed by inserting the arm into the slot where it cam from and by pushing the ball valve down. This will lever the component that holds the washer out.