Cistern is leaking water slowly into bowl?

All fixed.
Surprisingly the job was simple once I had some advice via the FAQ page on a plumbing site. It identified there was a fault in some of Geberit's flush valve seals. I could not get hold of Geberit themselves but bought some new seals on-line and fitted them myself.
The problem was that these grey coloured seals were deformed and "bubbled." Clearly the seal in that state was never going to form a water-tight seal. The replacements are clear (no colour) and were easy to fit. Cost was about £7 each. The task that was daunting me was how to remove the flush-valve to get at the seal at the bottom. However, it proved easy with just two spring catches to depress either side of the barrel structure and the whole flush valve lifts straight out - really easy in the end. The seals themselves just stretch over the plunger at the bottom and the whole thing took about 5 minutes.
Well worth the effort as I think I have lost many gallons of water over the period that the slow leak has been there. Hoping the next water bill will prove me right. Regards to All. Michael K.

Michael K
December 2010

Hello Fred (and Joe)
I have the same issue with my Ideal Standard Close Couple Cistern Toilet and my friend said the same as Joe ... but it is not the ball float device that needs adjusting to stop water going down the internal overflow. The water level is well below that where the overflow feeds water into the toilet pan.
My problem - like your description Fred - is the water is leaking out of the flushing mechanism - probably a seal leaking. The flush valve device appears to be a Gerberit Twico dual flush valve. Can anyone tell us how to dismantle and replace the seal or fix the problem. Many thanks.

Michael K
November 2010

Hi fred.
You will find that al you need to do is locate the swivel pin or ball cock float device and decrease your water level and that will solve your prolem.

Joe S Dybowski
November 2010