How to Fix a Leaky Toilet Base

Diagnose the leak first

Water pooling around the base of a toilet is a common problem. The source is usually a failed wax ring, but it can also be condensation, a cracked bowl, or a leaking tank-to-bowl gasket. Before you remove the toilet, dry the area completely and observe where the water originates. If the water appears only after flushing, the wax ring is likely the culprit. If the floor stays wet continuously, check the supply line, shut-off valve, and the tank bolts first.

A small leak can waste a surprising amount of water. The EPA notes that household leaks can waste 180 gallons per week, and toilets are often the source. Fixing a base leak promptly prevents water damage to your floor and subfloor, and avoids the risk of mold.

Once you are sure the leak is at the base, you will need to replace the wax ring. This is a repair you can do yourself with basic tools and a few hours. If you are unsure about the condition of the toilet bowl or the flange, inspect them carefully while the toilet is removed.

• Use a flashlight to look for cracks in the porcelain base.
• Check the floor flange (the plastic or metal ring that anchors the toilet to the floor) for damage or corrosion.
• If the flange is broken or recessed, you may need a flange extender or a full flange replacement.

Gather tools and supplies

For a wax ring replacement you need a few items: an adjustable wrench or pliers for the supply nut, a screwdriver for the tank bolts (if the tank is separate), a putty knife for scraping old wax, a bucket and sponge, and a new wax ring. You may also want a pair of rubber gloves and some shop towels. A caulk gun and silicone caulk are optional for sealing the base after the toilet is installed.

Wax rings come in standard sizes and fit most toilets. Some also have a polyethylene funnel or a rubber gasket combination. The standard wax ring is fine for most installations. If the flange is below the floor surface, you may need a thicker ring or a flange extender. Check the flange height while the toilet is off.

If you are replacing the toilet entirely, you can skip the wax ring and install a new one with the new toilet. For more on the complete process, see our toilet installation instructions.

Remove the toilet

Start by turning off the water supply at the shut-off valve, usually located on the wall behind the toilet. Flush the toilet and hold the handle down to drain as much water as possible from the tank and bowl. Use a sponge and a small cup to remove any remaining water from the tank and bowl. Disconnect the supply line from the toilet fill valve with an adjustable wrench.

Remove the caps covering the nuts on the floor bolts. Use a wrench or pliers to unscrew the nuts. If the nuts are corroded, you can cut them off with a hacksaw or use a nut driver. Once the nuts are off, gently rock the toilet back and forth to break the wax seal. Lift the toilet straight up and set it aside on a drop cloth or old towels. The toilet is heavy; ask for help if needed or use a toilet lifting device.

Stuff a rag into the floor drain opening to prevent sewer gas from entering the room while you work. Scrape away all the old wax from the flange and from the toilet's horn (the opening at the bottom of the bowl). Clean the area thoroughly so the new wax ring can create a watertight seal.

If you are removing the toilet for another reason, such as to replace the flange, refer to our toilet removal guide for detailed steps.

Inspect the floor flange

With the toilet off, examine the floor flange. The flange should be securely attached to the floor and the closet bolts should be snug. If the flange is cracked, broken, or rusted, the wax ring cannot seal properly. In that case, you may need to repair or replace the flange. Our guide on toilet flange basics explains the types and installation.

If the flange is intact but sits lower than the finished floor, use a flange extender to raise it. This is important because a wax ring needs to compress between the flange and the toilet exit. If the flange is recessed, a standard wax ring may not provide a good seal. You can also use a thick wax ring designed for this situation.

Check the closet bolts as well. They should extend about 1/4 inch above the bottom of the toilet base after installation. If they are stripped or broken, replace them. Many wax rings include new bolts; if not, purchase a set at any hardware store.

Install the new wax ring

Place the new wax ring on the flange, centering it over the drain opening. Make sure the ring is flat and not twisted. Some wax rings come with a plastic sleeve that you press into the flange. Press the ring down firmly so it sits stable.

Now you are ready to set the toilet. Lower the toilet straight down onto the wax ring, guiding the bowl bolts through the holes in the base. Do not slide the toilet sideways after it touches the wax, as this can distort the seal. Use your body weight to press down evenly, then sit on the toilet to compress the wax ring fully.

Install the washers and nuts on the floor bolts and tighten them alternately, a little at a time, until the toilet is snug. Do not overtighten, as this can crack the porcelain. The toilet should not rock. If it rocks, the flange might be uneven or the toilet might need shims. A wobbly toilet can break the wax seal over time.

Reconnect the water supply line and turn on the shut-off valve slowly. Check for leaks around the base and at the supply connection. Flush the toilet several times and inspect underneath the base with a dry paper towel. If water appears, shut off the water and check the seal.

Seal around the base with caulk

After the toilet is installed and you are confident there are no leaks, you can run a bead of silicone caulk along the floor where it meets the toilet base. This keeps water from a spill from running under the toilet and makes cleaning easier. Leave a small gap at the back to allow any future leak to be visible. If you notice moisture after caulking, the wax ring may have failed again.

Some plumbing codes require sealing around the base, but many homeowners prefer not to caulk the back edge so that leaks are detectable. Refer to your local code and consider the advice in this article.

If you are installing a new toilet and want to avoid a wax ring altogether, you can use a rubber toilet gasket. Our comparison of wax rings vs rubber gaskets covers the benefits and drawbacks of each.

Consider replacing the toilet

If the toilet is old, cracked, or constantly leaking despite a new wax ring, it may be time to replace it. A new toilet is not only a fresh start for the wax seal, but also a chance to improve water efficiency. The EPA's WaterSense program certifies toilets that use 1.28 gallons per flush or less, while still meeting performance standards. Replacing an older, inefficient toilet can cut indoor water use significantly.

If you decide to replace the toilet, you will need to remove the old unit and install a new one. That process is the same as the steps above, but you will be working with a new toilet. Follow the manufacturer's instructions for your specific model. You may want to review our toilet installation guide for additional tips.

Choose a toilet that fits your bathroom's rough-in measurement. Most toilets require a 12-inch rough-in, but you should measure from the wall to the center of the floor bolts to be sure. See our guide on how to measure rough-in for details.

What to pick for your repair or replacement

Questions

Can I fix a toilet base leak without removing the toilet?

Usually no. A base leak almost always means the wax ring has failed, and the toilet must be lifted off to replace it. You can temporarily reduce the leak by not flushing, but a permanent fix requires removing the toilet.

How long does a wax ring last?

A wax ring can last for decades if the toilet is stable and the flange is sound. However, a loose toilet, excessive floor movement, or repeated plunging can compress or crack the wax ring over time.

What tools do I need to replace a wax ring?

You need an adjustable wrench, a screwdriver or socket set for the tank bolts, a putty knife or scraper for old wax, a bucket and sponge, and a new wax ring. Rubber gloves and cleaning rags are also helpful.

Should I caulk around the entire bottom of the toilet?

It is common to caulk the front and sides, leaving a small gap at the back to detect future leaks. Some building codes require this. If you caulk completely and a wax ring leaks, the water can spread unnoticed and cause more damage.

Is a rubber gasket better than a wax ring?

Rubber gaskets are reusable and less affected by installation errors, but they may not work with every flange type. Wax rings are more traditional and inexpensive. Our comparison covers the trade-offs.