A toilet usually rocks or wobbles because the bolts that hold it to the floor have loosened, the floor under it is uneven, or the flange it sits on is broken. In some cases, a wobble means the subfloor has been weakened by a slow leak.
Loose Floor Bolts
Two bolts on either side of the base hold the toilet to the flange in the floor. Over time, they can loosen from normal use. Tightening them a little may help, but go slowly and evenly. Porcelain cracks easily if the bolts are overtightened.
An Uneven Floor
Tile, vinyl, or wood floors are not always perfectly flat. If the toilet sits on a high spot, it can rock even with tight bolts. Plastic shims made for toilets can fill small gaps under the base. A bead of caulk around the base can help hold it steady once it is level.
A Damaged Flange or Weak Subfloor
The flange is a ring attached to the drain pipe and the floor. If it is cracked or rusted, the bolts have nothing solid to hold. A toilet that has leaked at the base for a long time can also soften the wood below. Signs include a spongy floor, stains on the ceiling below, or a musty smell in the bathroom.
Why a Wobble Should Not Wait
- Rocking can break the wax seal under the toilet
- A broken seal lets water and sewer gas escape
- Leaks under the base can rot the floor over time
- A loose toilet can crack if someone sits down hard
If tightening the bolts does not help, or you see water around the base, it is best to stop using that toilet if you can. Resetting the toilet on a new seal lets a plumber check the flange and floor at the same time. If the floor feels soft, you can talk with a plumber about the subfloor at (833) 603-1840 to discuss next steps.