Eric Stewart: Running Off At The Mouth

Ballcock! What it is and replacing one

by Eric Stewart on Jun.03, 2009, under Home Stuff, Life

So Erika comes out of the bathroom one day and says, “There’s a little bit of water under the toilet.  I think there’s a leak.”  Later she texts me and says, “I know where it’s coming from.”

I had previously blogged about replacing the flapper.  Well, the thing that controls how much water comes into the tank after you’ve flushed is the ballcock (thanks to whoever put together such a great image and article for Wikipedia).  Our particular leak (which was coming, strangely enough, from the tank cover) was because our particular ballcock had water squirting out of the top as it filled the tank.  This is less than ideal; the water should be being routed to two places:

  1. Through the bowl fill tube into the overflow tube,
  2. And into the tank – but through the tank fill tube, not just out of the top of the fill valve.

Now, if you tinker (not to be confused with tinkle, which we all do), you’ll find that if you take the top of the fill valve apart, there’s an o-ring or two and some stoppers involved.  Should one of the o-rings not seal properly (either because it’s old or the fill valve assembly isn’t tight enough to allow the o-ring to seal, because of it’s crappy construction … guess which one I ran into?) you’ll have water coming out of the fill valve.  In our case, we had water coming out of the top of the fill valve, hitting the tank cover, and then leaking out onto the floor.  Not a lot, but enough …


Chances are this is partially due to when I replaced the flapper; I turned the water off to work on the toilet, and I think I turned it on too high when I turned it back on.  Thing is, a properly functioning ballcock shouldn’t have this issue.  The worst that would happen is that the fill valve shaft wouldn’t be able to shut the water off.

Okay – back on topic …

The most you should need for this repair (besides a new ballcock from your local homelowesdepot) is a wrench that can open wide enough to loosen the locknut on the old ballcock (and possibly tighten the new one) and maybe a screw driver if there’s something going on with your float ball and lift arm.  The ballcock I got had straight forward instructions, including reminders to turn off the water feed and drain water from the tank (might need to get a large sponge for this).  During the installation, keep an eye on where your bowl fill tube and lift arm are – you may need to route things differently based on how the rest of your tank is laid out.

The ballcock I got also leaked at the top of the fill valve, but only initally as the water was turned back on.  After that, everything worked as desired.

After a check on our guest bathroom, I’ve decided that that ballcock will get replaced tomorrow.


1 Comment for this entry

  • Eric

    Hey – something I’ve learned since I originally wrote this is that if your ballcock is leaking, you might want to turn the pressure up on the water feed. Ballcocks may need higher pressure in order to help an internal seal work properly.

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