I have a pretty new dual-flush toilet whose fill valve suddenly started leaking for no reason. A picture of the toilet is below:

enter image description here

Basically, the toilet flushes normally once the button is pressed. Water flows from the tank into the bowl. However, there is a problem with the fill valve. While water is supposed to refill the tank from the bottom, it instead leaks out through the gaps in the fill valve. (Picture below)

enter image description here

As you can see, water is coming out from the top of the valve and leaking out into the toilet. If I pull the lever up, the leak stops, but once I release the water starts leaking again. For whatever reason the tank never fills and the water keeps leaking forever.

Now, if I turn off the main valve and turn it back on again, the tank fills normally through the bottom. No water leaks through the fill valve. Of coure, the problem repeats if I flush again.

The problem with these new toilets is that there's no information online on how to fix them. Does anyone here know how to stop this leak and make the water go in through the bottom again?

enter image description here

  • 1
    Was there a small plastic hose going from near the top of that cap to that blue overflow pipe?
    – BMitch
    Sep 22, 2013 at 22:20
  • Nope thats the water with a slow shutter speed. It's flowing down underneath the lever.
    – user15232
    Sep 23, 2013 at 0:03
  • I haven't worked with your flapper design, so maybe it's different, but all the others I've worked on had that hose to fill the toilet back up after flushing.
    – BMitch
    Sep 23, 2013 at 1:57
  • When the toilet is continuing to fill, where is the extra water going? Is it reaching the overflow pipe? If so, you may need to adjust the height of the float (or the entire fill valve).
    – BMitch
    Sep 23, 2013 at 2:04
  • The extra water seems to be flowing into the tank, but it's flowing really slowly (trickling out of the top of the fill valve). I think that if I wait an hour, the water would slowly rise to the top and raise the cup, therefore stopping the leak. However, I want it to fill normally through the bottom rather than through the fill valve. Here's a more detailed pics of my toilet: bayimg.com/gaplEAAeo
    – user15232
    Sep 23, 2013 at 15:25

1 Answer 1


That's a fairly popular fill valve. To open it:

  1. Shutoff the water, you don't want a geyser.
  2. Lift the float to the top position.
  3. While holding up the float, push down on the top cap and twist the cap a quarter turn (I believe counter clockwise).

The cap will then lift off and you can inspect and clean any parts. Before reinstalling the cap, move any small parts to a safe location, get a small cup to place over the top of the valve, and turn on the water supply. This will jet water straight up from the top of the valve and clear out any debris.

Reinstalling the cap is the reverse of the above procedure. Put the parts back, position the cap back on top, lift the float, press down on the cap, and twist.

Note that if cleaning it doesn't work, it's fairly simple to replace this fill valve.

  • 1
    I took the cap off and cleaned it, but I now think that the problem lies elsewhere. The water is leaking out of the cap simply because the pressure pushing up on the cap is very high, and the cap cannot handle that high pressure. However, the high-pressure water should be escaping into the toilet tank and not pushing against the cap. I think that the problem lies with the fact that the water is not entering the tank - but why i don't know.
    – user15232
    Sep 23, 2013 at 0:34
  • 1
    the cap isn't the problem, its the valve under the cap. sometimes you can clean it, but there is a washer that wears out. the whole generic mechanism is less than $15 though if you buy the fluidmaster one that is basically identical to the american standard part.
    – Zach
    Mar 5, 2020 at 16:40