Why Is Your Toilet Rocking or Wobbling | Here’s The Fix

When you sit down on your toilet, does it lean a little to one side or the other? Do you feel like you’re sitting on a rocking chair rather than a toilet? Are you worried that one day the wobbling will evolve into a full-blown leak that might cause all sorts of expensive damage? 

Believe it or not, a toilet that rocks side to side is a common problem many homeowners face. The good news is that it isn’t difficult to fix, and you should be able to do it yourself. There are only a few reasons your toilet rocks, and I’ll go over them below. I will also provide step-by-step instructions for repairing the problem. I’ll start with what causes a toilet to wobble. 

What Causes A Toilet To Rock

As I said before, there are only a few things that will cause a toilet to rock, and they are:

  1. The flange or wax ring isn’t flush.
  2. The subfloor is uneven.
  3. The mounting bolts are loose. 

Let’s look into each one to learn a little more about why the rocking is happening. 

Flange Is Not Flush Causing A Pivot Point

The flange, located at the base of the toilet where it connects to the drainpipe on the floor, is sealed with a wax ring. If the flange or the wax ring is not flush, it can create a pivot point at the center of the toilet base that causes it to rock back and forth. 

A wobbly toilet may or may not be accompanied by leaking. Depending on whether your toilet is leaking or not, the fix may be as simple as inserting some shims under the base of the toilet to stabilize it, or the repair may require taking the toilet out completely to replace the flange or wax ring. 

Note: Never use an old flange or wax ring as they may be damaged and result in water or sewer gas leaks in your home. 

Your Subfloor Is Uneven

If you are sure the flange and wax ring is in good shape, the unsteadiness of your toilet might be caused by a subfloor that isn’t even. Wood flooring can warp over time, especially in bathrooms where humidity is constantly high due to bathing. While it is possible to stop the rocking by placing shims under the toilet base, the repairs may require more than this simple fix to stop the wobbling altogether. 

Note: If the subfloor is uneven, it could be because there is a leak under the base of the toilet. To identify a leak under the toilet, you will need to remove the commode and look for damage to the toilet itself and the flooring beneath it. 

Loose Mounting Bolts

Sometimes, the fix for a rocking toilet is as simple as tightening some bolts. The two mounting bolts (found on either side of the toilet base) that hold the toilet to the floor can become loose over time. If this is the reason your toilet is rocking to and fro, try tightening these bolts with a wrench. 

Note: Be careful not to tighten the mounting bolts too tightly as you could end up breaking the porcelain, which means this easy fix turns into a much more involved and expensive resolution. 

What Can Happen If You Don’t Fix It

While many people think a rocking toilet isn’t a huge deal, the fact is that if left to continue to wobble, a couple of not-so-pleasant things may happen. 

Sewage Leakage 

The flange and wax ring that connects your toilet to the drainpipe is designed to create an airtight seal that keeps sewer gasses from rising into your bathroom. If the connection isn’t flush and the toilet continues to rock back and forth, the flange or the wax ring may become damaged, which could allow toxic sewer gasses to infiltrate your home. These gasses not only smell bad, but they are also toxic and harmful to your health. 

Floor damage 

Whether your rocking toilet is accompanied by a water leak or not, the constant rocking to and fro can cause extensive damage to the flooring underneath the toilet. If your toilet is leaking water in addition to wobbling, water damage, which is difficult and costly to fix, is a certainty. 

As you can see, ignoring your rocking toilet can end up creating more hassle and expense than a mere wobble. 

How To Fix A Wobbling Toilet That Doesn’t Leak

If your wobbly toilet doesn’t include a leak yet, follow the steps below to stop the wobble. 

Step 1: Check The Mounting Bolts Are Tight

Sometimes, all a rocking toilet needs is a few tightening twists of its mounting bolts to stop the motion. Be careful when doing this, however, as tightening these bolts can crack the porcelain, in which case, you will need to replace the entire toilet. 

Use a pair of pliers or a small wrench to slowly tighten the bolts. Turn the bolts until they are just snug. Test the toilet for rocking. If it is still rocking, move on to the next step. 

Step 2: Cut Away Any Existing Caulk

If there is caulk around the base of your toilet, use a putty or utility knife to cut it away. This is an important step as it allows you to confirm there are no water leaks around the base of the toilet, and you will be able to see where the gaps are that cause your toilet to not be stable. 

Step 3: Wedge Plastic Shims Under Toilet Base

Using plastic shims (wood ones are not recommended for stabilizing a toilet because they compress over time and can rot with exposure to moisture), level and stabilize the toilet by pushing the shims into the gaps you’ve identified. Slide the shims as far into the gap as possible, and then check the toilet for stability by sitting on it and leaning in every direction. You may need to move or add shims repeatedly to completely stop your toilet from rocking. 

Step 4: Cut off Excess Shims Flush with Toilet Base

Once you are satisfied with the stability of your toilet, cut off any shim material that is sticking out from under the toilet base. Cut the shims as close to the base as possible to create a clean look. 

Note: You can use a dab of caulk under each shim to ensure it stays in place. If you do this, you should leave the caulk to dry overnight before you cut the excess shim away. 

Step 5: Re-Apply Tub Caulk Around the Base

The last step is to caulk around the base of the toilet to create a clean finish that hides the shims. Consider leaving the backside of the toilet base free of caulk, though, to allow water to escape should a leak occur. Caulking around the base can hide leaks until they have caused extensive damage to the surrounding area. 

If Your Wobbly Toilet Is Leaking

If you see signs of a water leak coming from underneath your toilet, there’s a good chance that something is damaged underneath. Before you can attempt any of the methods above for stopping the rocking, you must first address the issue that is causing the leak. 

Damaged Flange

A damaged flange or a flange that is not at the correct height, meaning it is not watertight, can not only cause your toilet to rock but also can cause your toilet to leak as the commode doesn’t have a solid connection to the drainpipe. To fix this issue, you will need to remove the toilet to either replace the flange or repair it with a flange repair kit (found at most home improvement stores). 

Damaged Wax Seal

As I mentioned before, the wax seal is designed to create an airtight seal that keeps sewer gasses from rising into your home through the toilet’s drainpipe. If the wax seal is compressed or otherwise damaged in some way, it can allow sewer gas and water to leak into your space. 

Again, you will need to remove the toilet completely to access the wax ring to replace it. Your local hardware or home improvement store will have wax rings to make this repair. 

Call In Professional Help

If all else has failed to fix your rocking toilet, or you don’t consider yourself qualified to make this kind of repair, don’t hesitate to call a professional plumber for help. A rocking toilet can be frustrating, but more than that, it can result in damage and expense you don’t want to have to deal with. As soon as you notice that your toilet is rocking, schedule a service call with a reputable licensed plumber immediately.

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Having renovated two homes and completed countless repairs, it was time to share this experience with the world. From repairing kitchen appliances to remodeling entire homes, my 30 years of experience will hopefully help you on your journey to a beautiful and functional home

Plumber and HVAC Technician | Website | + posts

As a retired Master Plumber Jamie has over 30 years of hands-on experience, making his plumbing knowledge second to none. He has also worked on both residential and commercial HVAC installation and repair projects.