I recently re-tiled my bathroom floor and removed the toilet to do so. I noticed that the builders had used grout around the base of the toilet when I was removing it and demoing the tile. Should I use grout or caulk around the base of the toilet? I've read some things that would suggest caulk is a better option.

The toilet is installed with the appropriate wax ring and is working fine. I do notice the slightest rocking if I push on the toilet. I'm guessing this is due to the floor not being completely level. The flange bolts are as tight as I'm willing to go with them w/o risk of cracking the porcelain.

Will the grout/caulk help to completely stabilize the toilet as well?

  • 1
    Here's some more information about caulking toilets to the floor, including relevant code sections.
    – Tester101
    Commented Jan 14, 2016 at 2:28
  • @Tester101 - Thank you. That is all very helpful information.
    – SBerg413
    Commented Jan 14, 2016 at 13:35
  • If your caulk is turning yellow, that's because you've used paintable caulking. Silicone is water- and urine-tight, non staining. Commented Mar 16, 2018 at 4:54
  • If you are rocking your toilet after installing it, you already have a leak unless you used a flexible foam rubber donut. Wax donuts will seal forever unless the toilet is even slightly moved. The wax bond does not move with the toilet. I learned this after installing the same toilet 3 times. I only install them once now.
    – user133626
    Commented Apr 7, 2021 at 14:50

4 Answers 4


Code requires toilets to be caulked at the floor, that, IMO is a mistake. If the toilet does develop a leak, it will be restricted under the toilet and the subfloor, and may leak for a while before it is detected. So much for that.

The toilet can be shimmed to keep it from rocking. Because of the rocking, what is not leaking now eventually will leak. The grout that the other installer used will act as shims to keep it from rocking as well, but back at the "if it leaks" issue. If you feel you need to seal it in some way, do not seal it 100%. Leave an inch or so not sealed at the back where it is not noticeable, that way it will look good and water can get out if need be.

  • Agreed that the caulk requirement is a mistake. Luckily the local inspectors here basically ignore it...
    – Comintern
    Commented Jan 14, 2016 at 1:55
  • 3
    Some people caulk the toilet at front and sides but not at the rear. Commented Jan 14, 2016 at 17:00
  • I'm curious what the rationale is in the code for the caulking requirement? It's hard to think what premise seemed so important for that to be in the code... Commented Mar 16, 2018 at 16:46
  • 1
    For commercial work, it would be for a matter of health code for cleanliness. Perhaps it's a carryover from that for residential...
    – Jack
    Commented Mar 16, 2018 at 17:59
  • Code requires toilets "shall be made water-tight" where the fixture comes in contact with the wall or floor. You can use w/e you want. Prob shouldn't be e.g., epoxy tho....
    – Mazura
    Commented Nov 20, 2021 at 2:59

The grout may help to keep the toilet stabile for awhile, but to ensure it remains level and secure you should install shims. I've used plastic building shims that can be snapped-off at 2 inch increments. Any flat material that is water-proof will do.

Loosen the bolts at the base of the toilet first. Place a level on the rim of the bowl and shim up the low side slightly past level. Snug the shim side and than the other side.

You can now either grout or caulk. Caulk is quick and easy to clean up. Grout will support the toilet better.



I don't care what code says. I have had 40+ houses inspected the past 15 years, never caulked one toilet, never had one inspector ask me to. I have had a few point it out and say they don't either but that is it.


  • caulk or grout does not stabilize your toilet. A flat surface does this. If your surface is not flat there are things you can buy to help under the toilet. Using grout to do this is ludicrous. It will eventually fail and be a mess in your bathroom. This is really half-assed

  • my first issue with caulk is that it would hide small leaks. I want to know right away if human waste was leaking into my house - don't care if it is a few drops a month. To me this is more than enough reason to never do it.

  • but then point number two is how do you expect your caulk to look after 6 months in your bathroom. Better buy yellow caulk. There is nothing worse than having guests over using your guest bathroom that your kids use seeing pee pee caulk.

There are some dumb codes in the book, some dumber than this one. No decent inspector would ever enforce crap like this as he wouldn't enforce the 50 other dumb codes in the book. I remember asking the last inspector that pointed it out, "Would I caulk it if the bathroom was carpet?" He says, "Who would carpet a bathroom?" I say, "Who would caulk a toilet?"

  • Most codes are not only for residential settings. In a public restroom the caulk is to keep things out from under the toilet, not to keep things in. If you don't caulk a public restroom, you'll have some nasty junk living under that toilet.
    – Tester101
    Commented Jan 14, 2016 at 4:18
  • 1
    If you have carpet under the toilet, you have bigger problems than how to caulk. That toilet's going to be rocking and rolling, and will be leaking in no time. Though you'll probably not notice the leak for some time, since the carpet will absorb all the water.
    – Tester101
    Commented Jan 14, 2016 at 4:25

I've always used clear silicone, for several reasons:

  1. It doesn't ruin the clean line of the white toilet against the flooring. White caulk, unless perfectly applied, results in a wavy, eye-catching line against non-white flooring.

  2. It bonds well and doesn't shrink significantly. Toilets are imperfect porcelain structures, and as such may rock slightly even on flat, level floors. A well-applied, concave bead makes for a very solid installation. My technique is to cut a small, angled opening on the tube nozzle, then trim the very tip flat. You shouldn't have to tool the bead if you're careful and smooth.

  3. It can be cut and removed fairly easily to replace or reset a toilet. Grout, not so much.

That said, I don't caulk the back side of the toilet for the reason others have mentioned--if there's a leak, you want to know about it.

As to yellow stains, I've never seen that issue. If that much urine is hitting the floor, the solution lies elsewhere.

  • Just FYI - The silicone may look good as this is exactly what I used to do but after taking a few toilets out in rentals I realized it was ruining my floor. Silicone on tile for a few years isn't coming up easy. Also this is assuming that the floor is tilted to the back of the toilet. if it is tilted towards the front you will need a pretty big leak to notice anything.
    – DMoore
    Commented Jan 14, 2016 at 4:44

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