I have a new type of cistern with small and large flush. When the toilet has been flushed, the cistern filled and the incoming water stopped, if I then turn a tap on elsewhere, the water surges in the cistern and continues to fill non-stop thus causing a constant overflow. Sometimes it starts on its own. This causes a lot of wasted water and it is lucky that we are not on a water metre. How can this be rectified?The model is from the QX Bathroom Experience range the Regal Suite.

Mrs Eileen Corbitt, June 2008

Not a regular occurrence, this, but I think I'd consider getting a new fill valve fitted. These usually have a couple of pressure reducers in the pack and the one suitable for the highest pressure should be used - its simply a plastic spiral that pushes into the fill valve from the bottom. An other way would be to have an isolator valve fitted into the toilet incoming water pipe. These can be turned right down so that the water fill volume is much less and the fill valve can handle things more easily. Should work!

John, June 2008