Toilet inlet valve.

As discussed in Mondays Blog. When a toilet is leaking into a pan, there are two possible causes.

The inlet valve allows water to fill the cistern until the float closes a washer onto the inlet valve seating. If the inlet valve washer has perished this will allow water to continually flow into the toilet cistern, causing the cistern to overfill and drain through the overflow into the pan. There are various makes and models of inlet valve one of the more common older ones you will know as a Ball Cock.

These valves can be problematic to replace. If in any doubts please call.