cistern filling when tap turned on?? HELP?????

[jontus5@hotmail.com]

can anyone tell me what would cause cistern to fill when tap is turned on????? Any help would be appreciated thanks.

[H20]

Hi

Which tap is it and how far away is the tap located in relation to the cistern?

What type of ball valve is in your cistern?

Does your cold water system suffer from water hammer (banging in the pipes)?