My Toilet is Leaking! Now What?

A leaking toilet can be more than just a nuisance; it can damage flooring, lead to mold growth and waste precious water. Leaks from underneath a toilet can arise from a number of reasons, but most of them can be effectively addressed with just a handful of tools and a minimal amount of time or expertise.

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Possible Reasons Your Toilet Is Leaking From the Bottom

Loose Floor Bolts

The bolts that secure your toilet to the floor can become loose over time. When this happens, water can seep out from the base when you flush the toilet.

To determine if loose floor bolts are causing a toilet leak, check for movement or wobbling when you gently push the toilet from different angles. If the toilet shifts or rocks, even slightly, the floor bolts are likely not securely fastened. Additionally, if you see water pooling around the base, specifically after flushing, and the toilet is unstable, this combination strongly suggests that the leak is due to loose floor bolts compromising the wax ring seal.

Wax Ring Failure

One of the most common reasons for a toilet to leak from the bottom is a failed wax ring seal. This ring sits between the toilet base and the floor flange to create a watertight seal between the toilet and sewer pipe. Over time, it can deteriorate or become dislodged, especially if the toilet rocks due to loose floor bolts.

A toilet leak caused by a wax ring failure usually manifests as water seeping or pooling around the base of the toilet, especially after flushing. If you notice a consistent wetness or water stains around the toilet base combined with a musty or sewer-like odor, the wax ring has likely failed. In addition, if you’ve tightened down the floor bolts and your toilet still rocks or feels unstable when you sit on it, that’s a strong indication that the wax ring is compromised.

Loose Toilet Tank or Bowl

Your toilet consists of two parts: the tank (that houses the water used to flush the toilet) and the bowl (where waste is deposited), which are held together with a couple of bolts containing a washer that keeps water from leaking out of the bolt holes. If these bolts become loose, the seal formed by the washers can become compromised and cause water to drip down the sides of the bowl and pool on the floor around the base of the toilet. Alternatively, the tank-to-bowl gasket that creates a watertight seal between the two components may not be forming an adequate seal because of loose toilet tank bolts, or because the gasket itself has failed.

To determine if loose bolts holding the toilet tank and bowl together are causing a leak, check for moisture around the bolt areas underneath the tank. Also, try to gently shift the tank side to side to see if it wobbles or moves. If there’s moisture around the bolt locations and/or the tank shows movement, loose bolts are likely the cause of your leak. If there is moisture around the connection point between the tank and bowl, a failed tank-to-bowl gasket is likely the culprit. If tightening down the bolts doesn’t stop the leak, the gasket may need to be replaced.

Now That You Know the Cause, Here’s How to Fix Your Leaky Toilet

Tighten Down Floor Bolts

Things You’ll Need:

• Adjustable wrench or slip-joint pliers

• Flat-head screwdriver (if necessary)

Step-by-Step:

Step 1: Locate the bolts. The toilet is held in place by two bolts that come up through the base of the toilet and are secured with nuts. Those nuts are typically covered by plastic caps.

Step 2: Remove the caps. Pop off the plastic caps covering the floor bolts. You can usually do this with your fingers, but use a flat-head screwdriver to pry them up if they’re too difficult to remove by hand.

Step 3: Tighten the bolts. Use the adjustable wrench or slip-joint pliers to tighten the nuts. After you’ve tightened a nut on one side a little, switch to tightening down the other side. This helps to ensure an even distribution of pressure and a better seal. As you’re tightening, be careful not to over-tighten the bolts, which can crack the toilet’s base. If you notice the toilet base starting to lift or the porcelain beginning to deform, you've tightened it too much.

Step 4: Check for stability and leaks. Once both nuts are tightened, gently rock the toilet back and forth to check for any movement. Flush the toilet a few times and check for leaks around the base of the toilet. If the toilet is stable and there are no leaks, replace the plastic caps over the bolts by pressing them down onto the bolt heads. If it still wobbles or the leak persists, you may need to replace the wax ring.

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Replace the Wax Ring

Things You’ll Need:

• New wax ring

• Adjustable wrench or slip-joint pliers

• Putty knife or scraper

• Nitrile or rubber gloves

• Sponge or rags

• Towel, drop cloth or tarp

Step-by-Step:

Step 1: Turn off the water. Turn off the water supply to the toilet by turning the shut-off valve (often located on the wall or floor near the base of the toilet) fully clockwise. Flush the toilet to drain the water from the tank and bowl, then use a sponge or rags to soak up any remaining water in the bowl.

Step 2: Remove the Toilet. Disconnect the water supply line from the base of the toilet tank by unthreading it counterclockwise by hand or with a pair of slip-joint pliers. Using an adjustable wrench or slip-joint pliers, remove the nuts and washers from the toilet bolts at the base of the toilet. These are typically covered by decorative caps, which you can pop off with a flat-head screwdriver or by hand. Carefully lift the toilet straight up and set the toilet on its side on a towel, drop cloth or tarp. If the toilet is too heavy or awkward for you to handle by yourself, consider recruiting the aid of a second person.

Step 3: Remove the old wax ring. Put on a pair of nitrile or rubber gloves and use a putty knife or scraper to remove the old wax ring from the bottom of the toilet and the closet flange (the fitting that connects the toilet to the sewer pipe and secures it to the floor) on the floor. Dispose of the old wax ring.

Step 4: Install the new wax ring. Place the new wax ring on the closet flange with the rounded or flanged side facing upward. If the wax ring comes with a plastic flange, it should be positioned so that it's inserted into the drain opening.

Step 5: Reinstall the toilet. Carefully lower the toilet back in place while lining up the mounting holes with the toilet bolts, then apply even downward pressure on the toilet to compress the wax ring and create a seal. Reattach the nuts and washers to the toilet bolts and tighten them down, being careful not to over-tighten them which can crack the toilet base. Reconnect the water supply line to the base of the toilet tank.

Step 6: Test for leaks. Turn the water supply valve back on and let the toilet tank fill, then flush the toilet a few times and check for any leaks at the base. If there are no leaks, replace the decorative caps over the toilet bolts.

Tighten the Toilet Tank Bolts

Things You’ll Need:

• Adjustable wrench or slip-joint pliers

Step-by-Step:

Step 1: Locate the bolts. These bolts typically come up through the bottom of the tank and go through the bowl's top rim, and are secured with nuts below the bowl's rim.

Step 2: Tighten the nuts. From below underneath the bowl rim, use an adjustable wrench or slip-joint pliers to tighten the nut by turning it clockwise. Tighten each side a bit at a time to ensure an even distribution of pressure, and avoid over-tightening which can damage the tank or bowl. If you notice the rubber washers inside the tank starting to bulge or the porcelain beginning to deform, you've tightened it too much.

Step 3: Check for stability and leaks. Once the nuts are tightened down, apply gentle pressure to the tank to ensure that it doesn’t move or wobble. Flush the toilet a few times and check for leaks around the bowl holes and gasket area. If water is still leaking from the connection point between the tank and the bowl, the tank-to-bowl gasket will have to be replaced.

Replace the Tank-to-Bowl Gasket

Things You’ll Need:

• New tank-to-bowl gasket

• Adjustable wrench or slip-joint pliers

• Sponge or rags

• Towel, drop cloth or tarp

Step-by-Step:

Step 1: Shut off the water. Turn off the water supply to the toilet by turning the shut-off valve fully clockwise.

Step 2: Flush the toilet. Flush the toilet to drain the water from the tank, then use a sponge or rags to soak up any remaining water at the bottom of the tank.

Step 3: Disconnect the water supply line. Using an adjustable wrench or slip-joint pliers, disconnect the water supply line from the fill valve located at the bottom of the tank by turning it fully counterclockwise.

Step 4: Remove the tank. Use an adjustable wrench or slip-joint pliers to unscrew the nuts connected to the bolts holding the tank and bowl together, then remove the bolts from inside the tank. Once the bolts are removed, lift the tank from the bowl and set it aside on a towel, drop cloth or tarp.

Step 5: Remove the old gasket. Peel or pull off the old tank-to-bowl gasket from the bottom of the tank. It's usually located around the large opening in the center.

Step 6: Install the new gasket. Position the new gasket over the large opening at the bottom of the tank.

Step 7: Reattach the tank. Replace the tank onto the bowl and align the bolt holes. Insert the bolts through the bowl's holes and secure them with the nuts you removed. Tighten the nuts on each side of the tank a bit at a time to ensure an even distribution of pressure,and be careful to not over-tighten them.

Step 8: Reconnect the water supply. Reattach the water supply line back to the fill valve at the bottom of the tank by threading it on counterclockwise until it’s snug.

Step 9: Turn on the water and check for leaks. Turn the shut-off valve fully counterclockwise to allow water back into the tank. Let the tank fill and then flush to check for any leaks between the tank and bowl.