I have a question about replacing wax gasket on a toilet. I hope my question is not too simple as this site is advertised as "serious DIY".My toilet is a Toto Aquia model ST464M, but I would think the question is applicable to most toilets? Although, be aware that with Toto you put a wax ring down and then cover with plastic cover. Toilet then goes on top of that. I.e. wax never touches toilet which I think is different than most brands.

I pulled by toilet up and replaced the wax seal. I put it all back together but then noticed small amount of water appearing at front of bowl. Clearly there is a problem. I think perhaps I used the wrong ring, or installed it incorrectly, or didn't place toilet down exactly right. Or some combination. I'm reasonably certain it's not leaking from the water input valve or the nuts/washers holding tank to bowl. If left alone with water input off, the tank water level will lower (perhaps 1/4" in 1 or 2 hours), and puddle will be present near front of toilet. This suggests to me a bad job of installing wax seal. Clearly I messed it up!

I'm new to working on toilets and my question is which wax ring should I use? Standard, or extra high. Or perhaps a non-wax one? Especially with my Toto model. Also, how do you know it's set right? That is, is there a good way to know that toilet is centered over hole and pushing down wax correctly? I'm lifting the toilet myself and placing it down. In the case of this Toto model there are some guide blocks on floor where toilet screws into.

I don't know if I'm seeing water because toilet is not centered over hole or if wax is insufficient to prevent leaking. How much tolerance is there for getting the horn of the toilet over the hole? Centimeters? Millimeters? Any suggestions how one man can do this?

Some more (possibly) relevant details. Floor is 12" x 12" tile. I'll try to post picture of how it looked when I took toilet off. Todo has a slightly different system for the wax ring. The wax ring is covered by a plastic piece and toilet goes on top of that.

Let me know if I can provide clarification/details.

Thanks, Dave View after removing toilet Wax ring is underneath this!

After unscrewing plastic and flipping upside down.  Notice was ring on underside


Based on comments by Jimmy I conducted the following test which clears a lot up (and leaves another mystery!).

I let toilet tank fill (turned on water). Turned off water. Added blue food coloring dye to tank. Waited about 1 hour. No color in bowl whatsoever, BUT Blue puddle on floor. Conclusion (as Jimmy suggested), wax gasket is not problem. It's leaking directly from tank. Not sure where... There is water in valve. There are 2 nuts/bolt attaching bowl to tank. There is center hole where flush valve goes and involves a big rubber gasket. I'm most suspicious of this. It was just loose. Not sure if it needs tape/putty etc. Will post picture. Or could be small hole in tank. It would have to be small. There's nothing obvious. Thanks all that are following this saga! And someone please reassure me that blue food coloring dye will not stain tile. Or my wife will be p1$$ed!.


Thank you everyone for all the brainstorming. I've got the toilet back up and working (and not leaking). It was definitely leaking from the tank, not the bowl as Jimmy and others suggested. For sure one of the problems was that it was leaking from the water input line and/or fill valve. I probably overtightened them, or I got a defective fill valve. The other two problems that I may have been guilty of were:

  1. Not seating the gasket that goes between bowl and tank correctly and/or not tightening the bolts between tank and bowl sufficiently.
  2. Not placing the flush valve in correctly (you need to turn it clockwise completely to seal).

I had the tank on/off more times than I care to admit, so I probably did all these things. And that might explain why I had trouble deciding where the leak was from! I think the water input line/fill valve was the main problem though.

Once it was pointed out how a toilet works and how to localize leak to tank (as opposed to bowl) it was only a matter of patience.

I thank everyone for their help and patience with me.

  • The wax ring if not properly seated to the toilet may cause some leaks. Some DIY folks don't clean the old ring and that's where it leaks. I usually use the more expensive urathane ? Core wax seals if the toilet may have movement.
    – Ed Beal
    Oct 8, 2016 at 1:00
  • Is the top of the flange below the level of the tile? It's hard to tell from the picture, but that gasket looks like it's resting on the tile, not the top of the flange.
    – Comintern
    Oct 8, 2016 at 1:03
  • Comintern, the top of the flange you are looking at is ABOVE the tile. This is where the "Todo" brand comes into play and I may need to post more pictures and/or instructions. The wax is below the plastic you are looking at in this picture. See the two little bolts? When you unscrew these and flip the flange over, you'll see the wax. I'm going to post a photo of that. Thanks for the quick response!
    – Dave
    Oct 8, 2016 at 2:01
  • That's deceptive. Sure looks like the flange is below the tile level. My Toto toilets didn't have the plastic thing or the guide blocks. I just used a normal wax ring.
    – topshot
    Oct 8, 2016 at 2:14
  • 1
    If you mean the alt tags like "After unscrewing plastic and flipping upside down. Notice was ring on underside", those will only show if the user has loading images turned off.
    – topshot
    Oct 8, 2016 at 2:19

2 Answers 2


"If left alone with water input off, the tank water level will lower (perhaps 1/4" in 1 or 2 hours), and puddle will be present near front of toilet. This suggests to me a bad job of installing wax seal"

There is an important clue buried within your question. There is no water from the toilet present at the wax-ring seal except when flushing.

Your problem/leak had nothing to do with your wax ring!

  • Hi Jimmy. Sorry to be such an idiot, but I don't understand what you mean. If hypothetically, I did a horrible job installing ring (or didn't install it) or didn't put hole of toilet centered over hole in ground, wouldn't it leak from there all the time, regardless of whether or not you are flushing? Do you mean the U-shaped trap is before the toilet floor junction so that it's just sitting in trap unless flushed? What else could problem be? Hole in toilet? How would I check for that?
    – Dave
    Oct 8, 2016 at 13:32
  • To be clear, are you saying that if I set up a toilet just on the floor (not even over a hole) and did not have water going into it, the water in the bowl and tank would stay at their same initial levels? If so, I agree this is a big clue. The toilet seems in good shape, I don't see any obvious cracks, holes, etc.
    – Dave
    Oct 8, 2016 at 13:35
  • 1
    "if I set up a toilet just on the floor (not even over a hole) and did not have water going into it, the water in the bowl and tank would stay at their same initial levels" Yes. If the level lowered any you have a leak. That is more common in the tank (flapper, bolt washers, inlet line connection or its seal to the bowl).
    – topshot
    Oct 8, 2016 at 15:21
  • 1
    If there's a leak in the bowl, more water will not fill it back up (hence why a bowl will lower over longer periods from evaporation). The tank is what has some kind of leak.
    – topshot
    Oct 8, 2016 at 15:27
  • 1
    I'd get that food coloring up ASAP! It could very likely stain.
    – topshot
    Oct 8, 2016 at 15:30

Holy crap these are complicated. It's possible that it's leaking from one of the other connections on the inside. I've never even seen one of these, but here's what I came up with.

Toto mentions using a Wax Ring / Seal so I suppose you can use whichever type you prefer. Personally, I've never seen a real wax ring fail if it was installed properly in the first place, but I've pulled out a fair share of non-wax rings that had failed.

Is there a good way to know if the toilet is centered over the hole and pushing down wax correctly? And what about tolerances?

The "socket" holds down the wax ring but I couldn't find where it says what height it needs to be at. The tolerances seem to be about nil. I'd think that if you can move it at all, then it's too low (add a second wax ring? See the second block quote). It looks as if it should fit like a glove. The positioning of the mounting blocks, and the height of the flange are paramount.

3) Turn the Socket or Modular Rough-In upside down. Firmly press a new wax seal onto the circular recess around the outlet opening. Turn the Socket or Modular Rough-In upright and lower it onto the position over the closet flange. With the unit properly aligned, press down firmly to set the wax seal. CAUTION: Do not move the Socket/Modular Rough-In after wax seal is set. –aquia_installation.pdf

If the flange is higher than or flush with the floor surface i use a single wax ring NO horn. If it is below the floor surface i put a regular wax ring down 1st then a 2nd wax ring with a horn on top with the horn facing down. –Complete Toto Aquia installation instructions written by Jamie Love terrylove.com

Any suggestions how one man can do this? Difficultly ;) Detach the tank if you have to.

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.