if its a syphon it can only go over the overflow.
if its a push button then it can go over the overflow or be passing the seal at the base of the flush valve.
hi-spec plumbing & heating (essex)
August 2009
Alter water level in the cistern there should be adjusitng rod/nut on the inlet float assembly.
Bob
August 2009
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix toilets.