My toilet cistern is leaking water straight into the toilet, just as fast as the cistern is filling. I don't know all the terminology but the washer that forms a seal between the pipe that drains down, and the siphon itself had a big blister on it that I popped, and now looks almost as good as new. It's very smooth, apart from one microscopic bobble where the blister was. However it's still pouring down, as if there's something else wrong with it. I did try to get a replacement washer, but the only one the plumber's merchant had looks the same (it's a Gerberit one, my old one is unbranded) but it's slightly thicker and a bit wider. This is the siphon (can't see a brand name on there)...

enter image description here

And here it is with the old washer attached (notice the washer doesn't go all the way to the edge, which I would have thought was necessary?!)

enter image description here

It slots and then 'twists to lock' into place in this...

enter image description here

I can understand a tiny bit of water leaking in given that it's not 100% perfect, but it's still leaking torrents so I wondered if anyone knows if something else could be broken inside (in addition to the washer). Should I just get a new siphon?

I can provide more pics / details if necessary. Really appreciate any help.



2 Answers 2


Personally I would go to Lowes or Home Depot and get the more conventional older style toilet siphon kit. You know with the flapper, fill valve, etc.
I am not familiar with the siphon you now have. Looks like some kind of internal failure of this piece of equipment. I am not a plumber, but have repaired a many toilets in my time. Just a suggestion. Good luck.

  • Thanks Randall. I think I may have fixed it though, but i'm not 100% sure yet as I need to let it settle down for a while: its still dripping slightly. Basically, the plunger you can see sticking out of the end needed pulling down fully before placing it back into the cistern. That plunger has another internal seal that stops water passing though the siphon. I'll post back later on whether it survives a flush :)
    – Richard
    Commented Sep 24, 2016 at 21:18

Fixed it. In addition to popping the blister on the washer, I took the top off the cannister (by prising the four very stubborn plastic clips apart with a screwdriver). The flush buttons press down on two rubber 'shock absorber' things, and one of them had somehow fallen over sideways. I put it back the right way up and now the plunger forms a proper seal inside when the canister is sitting back in the toilet

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.