Is Your Toilet Leaking Into The Basement? (Fix It Now!)

Upgraded Home Team
by Upgraded Home Team

Discovering a leaking toilet is stressful, especially if the water is damaging other parts of your home. Since water always runs downward, your basement is likely the victim of a leaking toilet. Deciding what to do next will depend on what caused the toilet to leak into the basement.

If your toilet is leaking into the basement or, perhaps, water leaks downwards when you flush the toilet, this indicates a problem with the toilet base. In most cases, the issue lies with the toilet’s wax seal, though it could also be as a result of a cracked base or connector pipe. Fortunately, a faulty seal is an easy fix, but anything more will require professional remediation.

Water damage can affect furniture, items stored in your basement, the ceiling, walls, and the floor. Water damage can also put the foundation of your home at risk. The timely repairs are critical and should not be delayed.

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Why is My Toilet Leaking Into The Basement?

There are many moving parts, connection points, and seals that could provide opportunities for your toilet to leak. Below are a few more common reasons water may be leaking.

The Wear and Tear of Seals Allow Water to Leak

If you notice some pooling of water at the base of your toilet, it could be the result of a bad seal. Your toilet is connected to a waste pipe that runs wastewater from the toilet to your sewage line.

The toilet is linked to this pipe with a toilet flange (AKA: closet flange) with a wax seal in between. The toilet flange is bolted down, typically at four points. The wax seal ring helps to create a watertight seal between the toilet flange and the floor.

Damaged Bolts or Gaskets Will Cause Leaks

The bowl of the toilet and the toilet tank are connected with two bolts with rubber gaskets. Over time, these rubber gaskets may become brittle and fall apart. It can also cause the bolts to loosen and create an opportunity for water to leak between the tank and the bowl.

Brittle rubber gaskets may also cause water to make contact with the metal bolts. Water helps the metal to rust, causing the bolts to become damaged.

They may not sit properly in their position or hold the toilet in place properly. Even if there is currently no leak, rusted bolts require replacement to avoid developing a leak in the future.

Leaking Water Supply from the Pipe

Your toilet is connected to the water supply via a hose which is attached by bolts and gaskets. This supply line can typically be found behind the toilet, either from the wall or the floor. On this line, you will notice a shut-off valve.

The valve and connectors all provide opportunities for leaks. Occasionally, a leak of this nature can be solved by simply tightening the connection points.

A Damaged Toilet Will Leak

The toilet itself might also be the source of the leak. Cracks in the tank or bowl create puddles on the floor, which can leak down into your basement.

Check the back of your toilet to see if it may be cracked at the base. If water only leaks upon flushing, then it’s probably a crack in either the connector pipe or the porcelain itself. If you find that the toilet itself is damaged, it will need to be replaced.

However, if the problem is with the connector pipe, you’ll probably need to call in a professional. It may be cracked, or the adhesive that seals the pipe components together might have worn off. Both of these issues have more complex fixes that you may not be able to handle as a DIY project.

Fixing a Leaking Toilet

Often, fixing a leaking toilet is a project that can be done with a few tools. Upon finding the leak source, you can decide if the project is something you can tackle on your own. If there is a lack of confidence, you need to call a professional.

Materials to fix a leaking toilet can be easily obtained at a home supply store. Depending on the leak source, you may need to purchase replacement bolts and washers, gaskets, toilet flange, or wax seal rings.

If the toilet has a crack in the bowl or tank causing a leak, do not repair it. Cracked toilets are a mandatory replacement.

Steps to Repair a Toilet That is Leaking

Listed below are the steps to repairing the leaks caused by the toilet.

Step 1: Shut off the Water Valve

Shut off the water supply valve. The water supply valve will be located behind your toilet, attached to a hose coming from either the floor or wall. According to your water source, you may also need to shut off the main valve.

Step 2: Remove All Water from the Tank and Toilet Bowl

Empty the toilet to the best of your ability. Flush the toilet to run the water from the tank to the bowl and into the waste pipe. Holding down the handle will continue the water flow until it is too low to do so.

You will likely still have a small amount of water in the tank and the bowl. Wear gloves to protect yourself, and use a sponge or rag to soak up excess water. Ring out the sponge or rag into a bucket or other container, which can be safely dumped elsewhere.

Step 3: Perform the Repairs as Needed

These are the possible repairs you may find and need to repair. Listed are the problems and the repairs.

  • If the seal is busted between the toilet tank and toilet bowl, remove the tank and scrape off the old seal. Replace the damaged seal with a fresh one making sure there is no remnant of the old seal. Put the tank back and replace it with new bolts to not have to remove the tank again.
  • If the seal is busted on the floor, remove the four bolts and the toilet. Scrape off the old seal and replace it with a new one. Put the toilet back in place and bolt it back down to the floor.
  • If the bolts are rusted, and water is leaking, replace the tank bolts with new ones.
  • If the water supply is leaking, remove the damaged pipe and replace it with new connections. All connections are held together by rings and bolts. Older models may be disconnected with wrenches.

Step 4: Test the Toilet for Additional Leakage

Once the problem is repaired, turn the water supply back on. Flush the toilet after the tank fills up and check for additional leaks.

Step 5: Clean Up the Water Damage

This step depends on how bad the water damage is. Mops and buckets or towels may be called for in use. Dehumidifiers would be wise to offer complete dryness.

Cost of Fixing a Leaking Toilet

The cost of the repair work will depend entirely on the source of the leak.

Bolts and washers can be replaced for as low as $1-2. Wax seals can be found for as low as $10. Toilet flanges are a little pricier than wax seals and can cost $20-40.

The labor depends on if the entire toilet is removed or extra plumbing is involved. Plumbers usually charge $60 to $100 per hour. Many have a minimum of one hour charge, even if it takes the plumber 30 minutes.

The more expensive fix for a leaking toilet is if the whole toilet needs to be replaced. Toilets can cost $200 to $400, depending on how fancy they are made.

If you’re replacing the toilet, it would also be wise to replace the seal. While the toilet is removed from the floor, it will save you from doing extra repairs later.

Water Damage to the Basement

If you are lucky, you caught the leaking toilet with enough time to stop a small problem from growing. If only a small amount of water leaked downwards, it may be safe. You might be able to get away with drying the area without leading to damage.

Check your ceiling and walls for moisture. If only a small amount is detected, you may be able to get away with drying the area with fans.

Evaporating water properly depends on two conditions: temperature and humidity. Creating a warm, dry environment can help make an ideal situation to dry areas quickly.

Open windows to allow air to circulate. Set up a few fans to help move recently evaporated moisture away from the wet areas to allow for maximum evaporation. If your basement is cooler, set up a space heater to encourage quicker evaporation.

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Protecting Your Basement from Future Water Damage

Water naturally seeks out the lowest point to settle. Your basement is at the highest risk for collecting water and developing damage from that water. Listed below are ideas for protection.

1. Keep the Drains Clear

Your basement may have a floor drain. If so, be sure to maintain it regularly. Keep the drainpipe clear from obstruction.

2. Seal Any Cracks in the Walls

When water goes between cracks, it will continue to erode the material and make the damage worse. Sealing these will prevent water from getting in and creating a bigger problem in the future.

3. Insulate the Area

Be sure pipes, ceilings, and walls are well insulated. Insulation will protect them from unwanted moisture seeping in either from the outside or from upper floors.

4. Use Protective Coatings to Waterproof the Area

Waterproof coatings and paints can add an extra layer of protection to walls. These sealants provide an extra barrier to hold back unwanted moisture.


Related Questions

Can a toilet leak from the ceiling?

Yes, it is possible for your toilet to leak from the ceiling. This occurs because of a worn wax ring. When it’s worn, water can seep through the ring each time you flush and may start to run down the walls, drip down your piping, and cause water damage on your ceiling.


Does homeowners insurance cover water damage from a toilet leak?

Generally speaking, homeowners insurance will help cover damage cause by plumbing leaks if the leak was abrupt and accidental, like if a pipe bursts or your washing machine supply hose breaks suddenly. Though, homeowners insurance does not cover water damage that results from improper maintenance. So, if damage was caused by your failure to repair the leaky toilet, your homeowners insurance will probably not pay for the repairs.


Can a leaking toilet cause mold?

Just like leaking water can cause damage to the structure of your home, even something as small as a toilet leak can lead to dangerous mold growth. If your toilet leak progresses to where you have leaking into your floor and walls, the mold can grow unbeknownst to you. This results in a very unsafe situation for you and the other occupants of your home.

Upgraded Home Team
Upgraded Home Team

We are a team of passionate homeowners, home improvement pros, and DIY enthusiasts who enjoy sharing home improvement, housekeeping, decorating, and more with other homeowners! Whether you're looking for a step-by-step guide on fixing an appliance or the cost of installing a fence, we've here to help.

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