Help needed with constantly filing toilet tank
April 9, 2016 10:17 PM   Subscribe

So in an effort to figure out why our water bill has doubled over the last six months, my wife and I have identified the likely culprit: our toilet.

It seems that instead of the tank filling up to just below the top of the overflow pipe, it keeps going, creating a slow stream of water running that has been adding up to a big and unnecessary expense. Given that it was also extremely slow to refill, we decided to replace the fill valve altogether and see if that fixed both problems. Well, the slow refill was eliminated, but the overflow problem persists. Adjusting the water level seems to have no effect, as the tube that delivers water from the fill valve to the overflow pipe continues to dribble out water, even after completing a normal refill that goes to the specified height. Any thoughts as to what the problem might be? (NB: we own, so it's on us to fix it.)
posted by Cash4Lead to Home & Garden (18 answers total) 4 users marked this as a favorite
If you have a thing that looks like this, adjust it to lower the water level where the float shuts the valve.
posted by qxntpqbbbqxl at 10:25 PM on April 9, 2016 [1 favorite]

did you replace or test the drain plug? if not, a slow leak there will cause your fill valve to constantly top off the tank.

It *could* be your fill valve failing to cut off at a complete tank fill, but if the drain plug isn't leaking, the tank would overflow, which you haven't mentioned.

Source: 1 attempted toilet rebuild, 2 complete toilet replacements, 3 complete tank innard troubleshootings and miscellaneous part swaps.

NB: I spent more on parts ($70) than a whole-toilet replacement including ring seal a couple years ago ($25 + $5 on sale at Home Depot). And it's totally gross, but I spent more on a plumber the first time I was working on these issues than a new computer. Check that valve.
posted by mwhybark at 10:32 PM on April 9, 2016

oops, forgot about the overflow pipe. yeah, check the drain valve seating, but also just set the shutoff to a level well below the overflow pipe. if it fails, keep troubleshooting. if it works, increase the level of water until it fails, then dial it back.
posted by mwhybark at 10:36 PM on April 9, 2016 [1 favorite]

Unless you have a wet floor, water is leaking out through the flapper valve and the supply is constantly running to keep the tank full. Adjusting the float level won't fix it. You need to fix the seating of the flapper.
posted by humboldt32 at 12:18 AM on April 10, 2016 [10 favorites]

i had that problem and the issue was water blisters forming in the rubber seal - I pulled it out, popped the bubbles with a pin and that fixed it.

Google your particular cistern type and running water, that will almost certainly get you a video of how to fix it.
posted by Sebmojo at 2:24 AM on April 10, 2016

the tube that delivers water from the fill valve to the overflow pipe continues to dribble out water, even after completing a normal refill that goes to the specified height.

For how long? If you mean this continues indefinitely then there's something wrong with the fill valve that controls it. If it only dribbles for a brief period after a flush then it's unlikely to be a serious problem.

Years ago I fixed a fill valve that malfunctioned immediately after installation because a bit of rust or debris had come loose upstream when I was messing with the supply pipes to make the connection, lodged in the valve and prevented it from closing completely. I remember it being fairly easy to open the top of the valve assembly and clean it out (supply valve turned off, of course).
posted by jon1270 at 3:46 AM on April 10, 2016 [1 favorite]

First troubleshooting step: turn off water to toilet and see if the tank remains full after a few hours. If it does, the flapper is fine. If it's not, replace the flapper. I would just spend $12 on the full fill valve/ flapper replacement kit though, so you can replace all the innards if need be. (It's not hard, I promise!)
posted by metasarah at 5:17 AM on April 10, 2016 [4 favorites]

the tube that delivers water from the fill valve to the overflow pipe continues to dribble out water, even after completing a normal refill that goes to the specified height.

If your cistern is like mine, it doesn't have a flapper as such. Instead there's a central riser full of Mysterious Business that incorporates the flush button actuators and the overflow pipe.

Well, the point of all that Mysterious Business is to manage a plug at the bottom. When you flush, that gets hauled upward off its plughole, then floats until the cistern empties in much the same way that a flapper valve would, but without the flapping.

The rubber rings that seal the plug against the plughole eventually perish. I managed to kill mine by pumping swimming pool water into the cistern over the winter; turns out that continuous exposure to even residual traces of pool chlorine does Bad Things to rubber.

Anyway, if that seal is leaky you get a constant dribble out of the tank and down inside the back of the pan. It looks like it must be coming from the overflow tube, but it isn't. It's just leaking down the hole that the flush water is supposed to dump through.

Your local hardware store should be able to sell you the correct replacement rubber if you give them the make and model of your cistern. Replacing the ring is easy - the whole Mysterious Business assembly is generally held in place with a few clips near the top, and once you ease those off the whole thing just lifts out. You might need to remove a float valve arm first to make room; this is usually most easily done by pulling out its pivot pin with pliers.

Here's a Youtube video covering one of the more common Australian makes. I would expect most of them to be pretty similar.
posted by flabdablet at 8:25 AM on April 10, 2016 [1 favorite]

Thanks, flabdablet! My toilet is of the Mysterious Business variety, so I will check out that video!
posted by Cash4Lead at 1:33 PM on April 10, 2016

I screwed around with the filling apparatus on my toilet for months trying to fix a similar issue.

It ended up being easier to just replace it because all the rubber seals had gone bad. If you have any mechanical aptitude at all, it's pretty straightforward.
posted by ArgentCorvid at 2:39 PM on April 10, 2016

So I replaced the seal on the flapper/riser (it goes straight up rather than lifting from a hinge). And … no change. I have the water shut off for now. Is it possible that I installed the fill valve improperly?
posted by Cash4Lead at 5:26 PM on April 10, 2016

More information: the flush valve is a Champion 4, which doesn't have a traditional flapper. I replaced the seal (the blue ring), but I think the problem is with the fill valve, along the lines of what jon1270 said.
posted by Cash4Lead at 8:05 AM on April 11, 2016

If you've got water continuously trickling down inside the back of the pan, there are basically only two ways it can get there.

One way is past the rubber seal on the flush plug / flapper; the other way is down the overflow tube, which bypasses that plug.

You can tell whether it's going down the overflow tube or not by looking in the cistern while the dribble is happening. If the water level in the cistern is all the way up to the top of the overflow tube, then that's where the dribble is coming from.

The only way the water level can rise that high is if the inlet valve doesn't shut the inlet all the way off before the cistern fills to that level. This, in turn, has two possible causes. Either the inlet valve seal is leaky, or the float that operates the inlet valve is adjusted to sit too high.

To check which of those is the case, grab the float and gently pull it upwards; this will turn the inlet valve off a little more forcefully. Splash a little bit of water down the overflow tube to drop the level by a millimetre or so. Keep applying gentle upward pressure to the float, and see whether the water level rises back to the top of the overflow tube or not.

If it doesn't, then the most likely thing is that the float wants adjusting to make it sit a little lower. You should find an adjusting screw on the inlet valve that lets you do this.

If the water level does keep rising despite a little extra upward pressure on the float, the inlet valve seal is leaking. That's usually down to a perished seal or a buildup of gunk in the valve seat. Inlet valves are usually fairly accessible and reasonably easy to take apart and inspect - you'll work it out pretty quick.

Backing up a little: if there's a trickle in the pan and the water level in the tank is not all the way up to the top of the overflow tube, you're looking at a leaking flush plug. Given that you've just replaced the seal on that plug, the most likely cause is that the replacement seal isn't seated quite right in the groove on the plug. When it's right, it will look flat or very slightly cupped, and completely symmetrical; if it's not quite right, it might look a bit rippled and maybe a little off-centre. Grabbing it by an edge and hauling it gently around the plug, without trying to stretch it, will usually persuade it to drop nicely into the groove within half a turn or so.
posted by flabdablet at 9:19 AM on April 11, 2016

If you can't make it seat nicely, try pulling it off, rubbing a bit of soap around the hole in the middle, and then re-fitting it. The soap will lubricate its passage back into the groove, then wash out with normal use.
posted by flabdablet at 9:24 AM on April 11, 2016

It's also worth giving the plughole that the flush plug sits in a rub over with a soapy cloth to get rid of any buildup there.
posted by flabdablet at 9:26 AM on April 11, 2016

Sorry, missed the part where the inlet valve is also new. Even so, if it's failing to shut off the fill before the level rises to the top of the overflow, and adjusting the float doesn't change that, it's still worth taking it apart and making sure its rubber seal is sitting where it's supposed to, that there's no grit lodged in its works, and that the face that the rubber seals against is smooth and defect-free.
posted by flabdablet at 9:35 AM on April 11, 2016

Another definitive check for whether you're dealing with a problem on the inlet side or the outlet side: shut off the water supply to the cistern and wait 15 minutes. If the level inside has dropped and there's still a dribble down into the pan, it's an outlet problem: the cistern is failing to hold all the water supplied to it. If the dribble has stopped, but starts again once you turn the supply back on, it's an inlet problem: the inlet valve is letting in too much water.
posted by flabdablet at 9:43 AM on April 11, 2016

Home Depot and the like will often have new toilets on sale for under $100. If you can't troubleshoot the problem, and if the current toilet isn't anything special then I would just replace the entire thing. It'll likely pay for itself in a month or two.
posted by any portmanteau in a storm at 12:22 PM on April 11, 2016

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