How To Fix A Toilet Leak

image of a toilet leaking at its base

When you’re worried about the water you just found on your bathroom floor (right near your commode) then rest assured that there are actually many possible causes of this issue. The goal is to address it soon before it has the chance to develop into a bigger plumbing problem. Be sure to consider the following possibilities before assuming that the toilet seal is broken. In most cases, the necessary toilet repairs are much less expensive than having wastewater pool beneath your toilet. In this article, we discuss how to fix a toilet leak.

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How To Repair A Leaking Toilet

Keep reading to determine causes and solutions for leaking toilets.

Top Two Factors To Consider When Dealing With Toilet Leaks

Toilet Condensation

One of the most common causes of water around the base of the toilet is condensation at the toilet tank. It has then pooled onto the bathroom floor. This is often called “tank sweating”. Tank sweat usually is the result of a significant difference between the air temperatures inside and outside of the tank. This happens particularly in bathrooms that are warm and steamy.

Tank sweating is most common in the summertime. However, it can occur at any time of the year. There are a number of easy ways to resolve this issue. These include installing a toilet tank liner to insulate the cold water at the tank interior. Another option is to install tank valves with anti-sweat features. These devices mix warm and cold water as it enters the tanks. This means that there is less temperature variance in or out of the tank. Sadly, it isn’t easy to definitively prove that the water pooling around your toilet is definitively tank sweat. In short, you will have to thoroughly clean the outside of the toilet tank with a towel to remove all moisture. Then, regularly check back to see whether water starts gathering on the tank exterior again.

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A Water Leak Inside The Toilet Tank

image of food coloring to test for toilet leaks

After you have ruled out the possibility of condensation or sweating as being the source of the water around your toilet, you should probably consider whether or not water is actually leaking from the tank. This is something that you can easily check. Begin by moving the tank lid. Be extremely careful because these lids are heavy, incredibly fragile, and often quite slippery given that they are wet. Then add some organic food coloring to the water in the tank.

After having added the coloring, do not flush your toilet. Wait instead for the water to change in color and settle. Let 15 minutes pass and don’t flush the toilet. If you find colored water on the floor that matches the colored water in the toilet tank or if you find colored drips anywhere at the tank exterior, then you know that water is leaking out of the tank.

You should then try to determine exactly where this water is originating from. When there are cracks in your porcelain tank, these are discolored. They will also be highlighted by the water that you’ve tinted. Tinted water can also be a big help in terms of pointing out leaks around rubber seals and bolts between the bowl and the tank or from the foam gasket that is positioned right where water enters the bowl via the flush valve.

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Water Leaking Between The Bowl & The Toilet Tank

This is another issue that the colored water test will help you detect. If you appear to have water leaking between the bowl and the tank, at the center, it could be necessary to replace the sponge gasket at the tank-to-bowl connection. You might need new washers for the bolts at the tank-to-bowl connection. Water that leaks from the gasket at the tank-to-bowl connection will leak a lot more right after the toilet has been flushed. If the leak is occurring just past the washers and bolts, it will probably appear nearer to the sides of the bowl, closer to the edge, and fairly far away from the bowl center. However, this isn’t always the case.

Leaks like these can be difficult to identify given that they can hide under the portion of the bowl that the tank hides. All bowls are different. One toilet bowl design could have a lower side at the front near the inlet hole, while another might have a lower side near the back of the bowl right near the inlet hole. There are even bowls that have low sides on side of the inlet hole. Water is always going to naturally flow towards the lowest point.

To identify and repair a toilet leak of this type, you will have to remove the tank from the bowl and replace the sponge gasket or washers as needed. The parts and the repair process can differ, depending upon the type of toilet you own. If you have decided to replace the rubber washers at the tank-to-bowl connection, this is also a good time to replace the bolts at this connection as well. Be sure to call a professional plumber, Like R.F. Ohl, for any type of plumbing repair that is beyond your skill level.

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Toilet Leaks At The Fill Valve Shank Gasket

Be sure to inspect the shank gasket which is found where the fill valve has been attached to the toilet tank. Also known as the ballcock, the fill valve is what allows water into the toilet tank. You will find the shank gasket connected to this valve at the tank interior. The colored water test is often helpful in identifying this type of leak as well. Look for developing cracks in the porcelain near the gasket or around it. If you don’t find any cracks here, you can probably stop the leak by simply tightening the shank nut, which is just below the tank. We recommend tightening this nut just 1/4 turn at a time as you check to verify whether or not the leak has stopped. If this doesn’t do the trick, a new gasket is probably needed. Call a plumber.

Valve Refill Tube Leaks

plumber repairing toilet

If your toilet leak appears to originate from the top and back of the tank, then check to ensure that the refill tube is still firmly connected to the overflow tube which is on the flush valve. Call a plumber for professional assistance.

Cracked Toilet Tank

Sadly, it is not possible to fix cracks in porcelain appliances and fixtures. Consequently, this means that you that you’ll have to have your toilet tank replaced or you’ll have to get a new toilet entirely. Call R.F. Ohl for superior plumbing services, including toilet repairs and replacements.


Defective Shut-Off Valve

Check the pipe connection found behind the valve to see if there is a water leak. This connection is closest to the wall. The presence of a toilet leak in this location can be fixed in two ways: first, tighten the shut-off valve and secure it on the pipe; and second, replace the valve with a new one. This will depend on what type of pipe and valve is currently installed. A professional plumber will be able to determine the best course of action.

Water Leak on the Supply Line

Look for any water leaks from nuts where the supply line ends. This is where the line secures the inlet for the fill valve of the toilet and the shut-off valve. These are located on both ends of the flex. In case you are dealing with a rigid line, you can try changing your supply washers with new ones. In some set-ups such as single-piece units, the supply line is directly attached to the shut-off valve. To fix this, use flexible water flexes (stainless steel is recommended) because they are sturdy, reliable, and easy to attach. A single-piece valve and supply line can also be replaced with two separate pieces of a flexible line and a shut-off valve. For all plumbing repairs, it is always best to call a plumber.

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Water Everywhere

In many households, the toilet is the fixture that lies lowest and closest to the floor. This explains why excess water from the bathtub or the shower tends to pool in the toilet area. Very often, people mistake this scene as proof that the toilet is leaking water and proceed to fix the problem with that issue in mind. This is not only unnecessary but also expensive, especially if the real reason there is water on the floor around the toilet is caused by a simple problem. A practical remedy would be to place one or two throw rugs on the floors and wait for them to absorb the water. The problem is fixed when the water disappears.

Water Leak From Under The Toilet

A damaged wax ring can cause wastewater to seep through if water backs up lower down the supply line. However, even when the wax seal is damaged, the water that flushes through the free drain should not seep through the closed flange under the toilet and into the toilet floor. Water from this source drops down from its source in the toilet and runs through to the wastewater line. When wastewater pools on the toilet floor (judging from its color and odor), the problem requires a lot more than replacing a damaged wax ring.

It’s likely there is no recurring overflow with the toilet but water is obviously backing up, finding a route from under the toilet to overflow into the floor. Fortunately, this problem is fixed by resealing the toilet bowl and replacing the wax ring. Caulking the toilet bowl to seal it at the base will also help. There is also the possibility that there is a stoppage in the waste lines. If this is the case, a wax ring replacement will not be enough and may even fail since wastewater will continue to back up and damage it.



Sometimes it is more affordable to contact a plumber. It takes experience and the appropriate know-how to fix a leaking toilet. Many homeowners might take on the task of fixing a toilet. Therefore, they find themselves frustrated because they end up being at square one after spending a lot of effort and hundreds of dollars. Be sure to contact a plumber who is reputable and can fix your leaking toilet properly.

For any plumbing issues that you need to be addressed, including leaking toilets, be sure to contact R.F. Ohl. Our certified and experienced plumbers have the skills necessary to get the job done accurately, quickly, and affordably.

Call R.F. Ohl For Trusted Plumbing Services

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When you need dependable plumbing services, do not hesitate to call R.F. Ohl. Our company is one of the most trusted plumbing companies in the Poconos and the Lehigh Valley, Pennsylvania. We offer services such as toiler repairs and replacements, water leak detection, installation of water-efficient plumbing fixtures, water heater maintenance, and more. We also provide the best solutions for any plumbing repairs you need while ensuring your family’s needs and budgets are met.

Rest assured, we have the most affordable plumbing services in the area. Each of our plumbers is licensed and experienced to ensure all services are done correctly. All our work comes with a guarantee. Contact R.F. Ohl to schedule a free estimate with us today.

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