How to Fix a Wobbly Toilet

Steps:

1. Shut the water off to the toilet. Flush the toilet until the bowl is empty. Use a sponge and a bucket to remove the remaining water. Disconnect the water line from the toilet.
2. Remove the bolt cap covers, nuts, and washers from the closet bolts on both sides.
3. Carefully remove the toilet and place it on the drop cloth.
4. Check the wax ring for deformities. This could be the cause of the wobbly toilet. The wax ring will need to be replaced in either case, so remove the old one with a putty knife.
5. Since the toilet is already off, it’s always best practice to check the condition of the toilet flange and repair as necessary.
6. Check the floor for level. If it’s out of level, it may be necessary to shim the toilet.
7. Put new closet bolts on the toilet flange and replace the wax ring.
8. Put the toilet back on the closet bolts.
9. Put shims underneath the toilet until it is level.
10. Add the cap base, the washer, and the nut to the closet bolts on both sides of the toilet. Alternate tightening each nut on both sides until the toilet is securely connected.
11. Cut the excess off the closet bolts using the hacksaw. Cover the bolts with the caps.
12. Reconnect the water line and turn the water back on.

Don’t overlook the plastic base cap — it’s not just cosmetic. The base cap transfers the force of the washer evenly against the porcelain, preventing the nut and washer from deforming under pressure and damaging the china. Without it, the hardware can dig into the toilet base and cause an uneven seal.

Pro Tip: When tightening the closet bolts, alternate sides and use a gentle touch. As demonstrated in a This Old House project visit, overtightening is a common mistake — tighten the nuts too much and the porcelain base will crack in a heartbeat. The goal is a snug, secure connection, not maximum force.

Expert Insight: During a This Old House project visit, Richard Trethewey stressed the importance of verifying that the flange is properly secured to the subfloor with non-ferrous (rust-resistant) screws driven into plywood or structural framing. If the flange isn’t permanently secured to the floor, the toilet will continue to rock regardless of how well you tighten the closet bolts.

Resources:
Everything Richard used for this project, including the wrenches, closet bolts and caps, and toilet shims, can be found at home centers.

Instead of using a traditional wax seal, Richard used a flexible rubber gasket manufactured by SaniSeal.