Tightening bolts on the base of a toilet is the one thing about toilet installation that has me the most nervous. They say not to over-tighten, but how tight is too tight before the porcelain is subject to cracking? Do I tighten until I can't tighten anymore? Do I tighten it just before I think it's at its tightest?

  • 11
    If the porcelain cracked, it was too tight!
    – hookenz
    Commented Jul 8, 2013 at 0:18
  • 1
    Last one I installed used the guideline of "tighten fully by hand, then use the wrench to give it one quarter turn more." Check what your unit's manufacturer suggests.
    – keshlam
    Commented May 21, 2016 at 0:59
  • While many of the answers boil down to "so it won't leak" I am mostly concerned that small bowl movements will pull the bowl away from the seal. Commented Feb 22, 2020 at 18:30

8 Answers 8


I start by hand tightening as much as I can, then I tighten a little on each side and check if the toilet moves. If it does then I tighten a bit more, check and repeat until there's no movement. You're trying to avoid bowl movement, so that it doesn't shift or fall over, not to hold the floor up by the toilet bolts.

As tight as you can go will probably snap the porcelain (with a good socket you can torque a nut onto a bolt quite a bit). Until you think it's about to snap is just guessing.

Snug. No movement. Enjoy.

"Too tight" is a sixteenth of a turn past where the porcelain snaps :-)

  • 3
    The length of your wrench will affect the "feel" of tightness. I have a ratchet with a 2" handle (the most expensive wrench in my toolbox) that I use whenever I don't want to over-tighten a nut (and don't have an explicit torque setting).
    – kdgregory
    Commented Oct 15, 2011 at 23:11
  • 1
    Good answer. I basically tightened the nuts to the point where the toilet was level and did not move at all. One last question, though: When I lay my level across the bowl and apply upward pressure on either side of the bowl, the level indicates that there is very slight movement because the bubble moves a tad to the left and right (still within level parameters). However, I can't feel the movement myself. Does this seem fine? Commented Oct 16, 2011 at 17:36
  • 1
    @oscilatingcretin I would personally be ok with it, since the normal operating conditions will have pressure in the downward position, but then I'm more paranoid of over tightening than falling off.
    – Stephen
    Commented Oct 17, 2011 at 3:08
  • 3
    Exactly - the point of the bolts is to hold the toilet in place, NOT to create the seal. The seal is created by the wax ring. One quarter turn too far on that bolt and you've ruined a multi hundred dollar toilet. If it doesn't move when you sit on it, it's tight enough! Commented Sep 27, 2012 at 10:24
  • 7
    I almost sprayed coffee on my screen when I read "You're trying to avoid bowl movement". :)
    – aphoria
    Commented Sep 27, 2012 at 12:40

One thing that will help prevent the porcelain cracking is to use a rubber or plastic washer between the head of the bolt and the bowl.

This will take some of the "excess" force by deforming slightly, and by checking for the washer deforming as you tighten you'll have an extra visual check that you've applied enough force.

  • Yeap, not only will it take excess force, it will provide good hold of the toilet so that it doesn't swing.
    – sharptooth
    Commented Sep 27, 2012 at 10:09

Best practice is to hand tighten nuts, sit on toilet to assist with setting wax ring, tighten nuts to a point of being snug and alternate tightening nuts, then sit back on toilet and if toilet moves, tighten slightly. Check if toilet is level, shim to level, and flush toilet. If leaks, repeat process of sitting on toilet and slightly tighten nuts in an alternating fashion.

  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Commented Nov 3, 2019 at 11:56

My grandfather was a master plumber for more than 50 years. I asked him one time how tight to make a sink faucet shutoff valve connection. His answer is a classic ... "Tight enough so it don't leak". There is a lot of wisdom in this. The answer for the toilet is the same thing, not too tight but tight enough.


The toilet can wiggle for two reasons: bolts not tight or floor not even (hello old houses!). After tightening the bolts a little bit and making sure you really set that toilet on the ring, see if you need to shim one or two gaps. In my case, i too was worried about cranking down hard on the bolts. The shims stabilized the toilet nic


When you put the toilet in place, with the wax sealing ring between the toilet flange on the floor and the toilet itself, the toilet will be held off the floor a bit by the wax ring. Sit on the toilet backwards (facing the tank - so you can see and reach the nuts) to squish the ring in place sealing the toilet to the flange on the floor. Tighten the nuts on the closet bolts (that attach to the flange) such that the toilet is flat on the floor without rocking.

Tighten it down a bit on one side then the other, then do it again. Rinse and repeat, until the toilet is flat on the floor. If you tighten it too much, you can pull the closet bolt out through the flange, ruining the flange or breaking the porcelain.

DO NOT tighten it as tight as it will go, like you're building something or working on your car - you'll break the flange, chip or crack the porcelain or both.

Most toilets are made of vitreous china. Vitreous china is a glass based enamel coating / glazing technique that is added to porcelain to make it more durable, denser, and shinier. It is also what fine dinner ware, plates, dishes and cups are made of.


Whatever length wrench you're using, choke up on the handle all the way.

"Too tight" begins once you start deforming the washer.

Once you do start to deform the washer, you have to toss the, "hand tighten, then 1/4 turn with a wrench," out the window (not that I've ever found that sentiment to be satisfactory). I've never cracked a toilet by over tightening its bolts. The washers that come with a bolt kit are intentionally flimsy.

If there's a word for the day, it's : snug (for which you either need years of experience, or one cracked toilet, to know when to say when).

My preferred finishing touch is, once it's sung, grout it in place (keeps hair from getting stuck in the grove, and other yuckiness) and then I guarantee, it will not rock. My preferred tool, is my little six inch adjustable wrench. I don't choke up on it, but I know when to say when.


You should never grout or silicone your toilet in place. If for some reason you have a leak at the connection between the flange and wax ring it will collect under the bowl and by the time you notice it, it will may have ruined the floor under it not to mention the condensation that is being created in that pocket which you created by sealing it. Also, the mess you will have to clean up when you eventually replace that toilet. I would much rather remove hair and "yuckiness" then grout or silicone with more "yuckiness" attached to the silicone or grout and or run the risk of damaging the floor to remove it... as far as tightening goes, hand tighten, go one full turn with perfered tool, sit on the bowl, slightly lift your left leg and right leg to see if the toilet rocks if it does turn bolts a half turn, rinse repeat till no Rocking occurs, assuming you have a fresh nice flange. 534 Water closets installed. $

  • Except it's code in some places to caulk around the toilet, so I caulk all the way around but leave a space in the back for water to come out if that happens Commented Apr 28 at 17:02

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.