I've noticed that I'll hear this toilet turn on randomly, so I turned off the water supply to monitor it. In about 12 hours the tank water level dropped a good amount. I tried replacing the flapper, made sure the tank screws at the bottom were tight, but I'm out of ideas. There's no water leaking on the floor. I used food coloring to confirm that the water is leaking down into the bowl. Not sure where else the leak could be?

Water level at 8 pm yesterday:


Water level at 8 am today:


Also, the toilet itself is not level, but I'm not sure if this has anything to do with the problem.

To clarify -

Food coloring in tank to verify water is NOT leaking into bowl, correct?

How tight is your chain? It should have some slack.

EZ
Toss this flapper or save for some other toilet
Gently SCOUR the RIM on the outflow pipe to insure a tight seal to new flapper

NEW flapper this time one that's chlorine/CHLORAZONE resistant
check chain length repeatedly for faultless action
https://www.amazon.com/Korky-2000BP-Classic-Plus-Flapper/dp/B000KKUC62

Failure = replace entire assembly and with nothing "on sale" nor cheap
or call Plumber w/warranty = never have to touch it again.

dudeabides said:

---

If you confirmed that the flapper is fully seated (i.e., there is nothing keeping the flapper from fully sealing on the valve body, like a spec of grit), then I would replace the entire flush valve assembly.

---

There was no grit. I'm running an experiment to test the flush valve assembly. I removed water from the tank to where the level is below the lip of the pipe that the flapper covers. I put food coloring to see if anything is leaking below the flapper. I'll check the bowl for red dye in a couple of hours.

TexAg1987 said:

---

To clarify -

Food coloring in tank to verify water is NOT leaking into bowl, correct?

How tight is your chain? It should have some slack.

---

I know water is not supposed to leak in the bowl. I'm testing whether or not that is happening. There is slack in the chain.

tgivaughn said:

---

EZ
Toss this flapper or save for some other toilet
Gently scour the rim on the outflow pipe to insure a tight seal to new flapper

NEW flapper this time one that's chlorine/CHLORAZONE resistant
check chain length repeatedly for faultless action
https://www.amazon.com/Korky-2000BP-Classic-Plus-Flapper/dp/B000KKUC62

Failure = replace entire assembly and with nothing "on sale" nor cheap
or call Plumber w/warranty = never have to touch it again.

---

Could the toilet being slightly not level cause the flapper to not get a good seal?

Thunderstruck xx said:

---

dudeabides said:

---

If you confirmed that the flapper is fully seated (i.e., there is nothing keeping the flapper from fully sealing on the valve body, like a spec of grit), then I would replace the entire flush valve assembly.

---

There was no grit. I'm running an experiment to test the flush valve assembly. I removed water from the tank to where the level is below the lip of the pipe that the flapper covers. I put food coloring to see if anything is leaking below the flapper. I'll check the bowl for red dye in a couple of hours.

---

Well this experiment I ran didn't show any leaks, so now I'm thinking the flapper is not getting a good seal whether it is new or not. I've only tried fluidmaster brand flappers. Are there better brands of flappers I should try?

Bad flapper or cracked fill tube


Replace the flapper first and if that does not fix it then replace the fill tube

I like fluidmaster flappers but have also had good luck with korky

Check that the fill tube only goes down into the overflow pipe about an inch. If the tube is too long it can siphon water into the bowl through the overflow pipe.

Me thinks not, sorry

The only odd event out in right field such as this was when the chain configuration actually draped down, got sucked in & spoiled the seal
Right field is sometimes a good place to go to find very ODD things afoot that "never happen".

tgivaughn said:

---

Me thinks not, sorry

The only odd event out in right field such as this was when the chain configuration actually draped down, got sucked in & spoiled the seal
Right field is sometimes a good place to go to find very ODD things afoot that "never happen".

---

I only use the Korky brand of flappers

I just tried a Korky flapper and it made no difference. I guess it has to be the flush valve assembly.

Good call. Divide & conquer...process of elimination.

Did you get it fixed?

Caesar4 said:

---

Good call. Divide & conquer...process of elimination.

Did you get it fixed?

---

I need to get the plumber scheduled to look at replacing the flush valve assembly. The home builder's plumbers can be hard to work with so it could be a while. My worry is that the toilet not being level could be the cause. Does a toilet have to be perfectly level to avoid this kind of leak?

No.

If you are handy at all, it is not a hard job.

Thunderstruck xx said:

---

Caesar4 said:

---

Good call. Divide & conquer...process of elimination.

Did you get it fixed?

---

I need to get the plumber scheduled to look at replacing the flush valve assembly. The home builder's plumbers can be hard to work with so it could be a while. My worry is that the toilet not being level could be the cause. Does a toilet have to be perfectly level to avoid this kind of leak?

---

No, it doesn't have to be level. Your fill tube should have part of the top of the tube above the water level in the tank. It shouldn't be close.