A wobbly toilet is one of those things you notice every time you sit down and then forget about until the next time you sit down. I had one for months. It did not leak, it did not run, it just rocked a little, which was enough to drive me crazy.

The fix took me fifteen minutes and a pack of plastic shims that cost four dollars.

Find the Gap

Rock the toilet gently and watch the base. The wobble comes from a gap between the toilet base and the floor. Push down on each corner to find where it moves. On mine, the front right corner had a clear gap you could slide a coin into.

Slide in the Shims

Plastic shims are thin wedges sold in packs at any hardware store. Slide them into the gap from both sides of the toilet base, a pair of shims facing each other, and tap them in until the toilet stops rocking.

The paired wedges act like a mini leveling jack. Tap a little at a time and keep checking by rocking the toilet with your knee.

Cut and Cover

Once it is solid, score the shims with a utility knife and snap off the excess sticking out past the base. Then run a bead of caulk around the base to seal it and hide the shim ends.

Do not caulk before the toilet is level. I almost did that and the caulk would have locked the wobble in place forever.

When to Call a Plumber Instead

If the toilet rocks because the flange underneath is broken or the floor is soft, shims will not fix it. Press on the floor near the base. If it feels spongy, you have a different problem.

A wobbly toilet can crack the wax seal over time and start leaking, so it is worth fixing early. Mine has been rock solid for a year and I have not thought about it since.