Toilet Leaks When Flushed? Here is how to Fix it Fast
Last Updated on January 5, 2022 by toilethaven
Why Does My Toilet Leak When Flushed?
A leaking toilet is characterized by water pooling around the base or a damp basement ceiling. Toilets will most likely leak between the tank and the bowl or around the base when flushed.
A toilet that leaks when flushed is caused by loose tank bolts, cracked bowl, worn out tank to bowl gasket, broken closet flange, worn out wax ring or even a cracked flush valve. The first step to fixing the problem is by identifying the source of the leak.
If your toilet leaks between the tank and the bowl when flushed it is a sign that the tank to bowl gasket (spud washer) is worn out, or the tank bolts are loose. A toilet leaking from around the base when flushed indicates that the wax ring is not sealing.
A hairline crack on the toilet bowl can also cause it to leak. If the crack extends to the bottom of the toilet/toilet trap you will notice that the bowl cannot retain any water, and a foul smell will fill the bathroom.
Worn out toilet tank to bowl gaskets and toilet wax rings are however the ones responsible for most toilet leaks.
Replacing the toilet tank to bowl gasket and tank bolts will fix a toilet that leaks between the tank and the bowl when flushed. If however your toilet leaks from its base when you flush, you will need to replace the toilet wax ring assuming the bowl is not cracked.
What is A Toilet Wax Ring?
A toilet wax ring is a thick wax molded on a plastic ring that provides a water tight seal between the bottom of the toilet and the to of the toilet flange. It also prevents sewer gases from coming up to the bathroom and entire toilet.
A toilet or closet flange is a round pipe fitting screwed into the bathroom floor that connects the toilet to the drainpipe. Two bolts connects the closet flange and the toilet and therefore securing the toilet firmly on the floor.
A wax ring is sandwiched between the flange and the toilet. An alternative to using a wax ring is a rubber gasket seal. The rubber seals are less messier than wax rings.
If your toilet is leaking from the floor or the basement ceiling, it means the wax ring is not sealing as it should. This is mainly caused by a broken toilet flange or loose toilet bolts which makes the toilet to start wobbling. A wobbly toilet will after sometime unseat the wax ring and hence the leak.
What is a Toilet Tank to Bowl Gasket?
A toilet tank to bowl gasket also known as a spud washer is a rubber gasket that provides a watertight seal between the toilet tank and the bowl. It is normally installed on the outside of the flush valve where the flush water leaves the tank and enters the bowl.
If your toilet leaks when flushed between the toilet tank and the bowl, ie means the toilet tank to bowl gasket is worn out, tank bolts are loose or the flush valve is cracked. This however only happens on two-piece toilets and to fix the problem you will most likely have to remove the toilet tank.
How to Fix a Toilet That Leaks When Flushed
- A wax ring/ rubber seal
- Tank to bowl gasket with bolts, nuts and washers
- Adjustable wrench
- Flathead screwdriver
- Putty knife
- Empty bucket
- Mini-hacksaw (optional)
- Rubber gloves
- Old rag/towel
1. How to Fix a Toilet that Leaks at the Base When Flushed
When your toilet leaks from the base when flushed, you will need to remove the toilet in order to replace the wax ring which is causing the leaks. An upstairs toilet that leaks when flushed will be noticed by water in the ceiling or in the basement.
To fix a toilet that is leaking from the base, you must replace the wax ring with another wax ring or rubber gasket. Let us see how you replace a toilet wax ring.
Step 1: Disconnect Water to the Toilet
- Look for the toilet shut off valve. It is located at the rear wall of the toilet mostly on the left hand side.
- Turn this valve clockwise. If you have the push/pull valve, pull it outwards to turn off water to the toilet tank.
Step 2: Drain the Toilet Tank
- Flush the toilet and hold the lever down to flush down as much water as possible.
- Remove the toilet tank lid and place it away in a safe place. It can crack easily.
- There is a little amount of water still left at the bottom of the toilet tank. Use the sponge to soak it out and squeeze into the empty bucket.
- Look for the water supply line connecting the shut off valve to the underside of the tank. Disconnect it. Always attempt to disconnect it with your hand before attempting with a wrench.
Step 3: Remove the Toilet
- Prior to removing the toilet, you will need to remove the water at the bottom of the bowl, otherwise it will make a big mess once you remove the toilet.
- Use the sponge to soak up and empty the water into the bucket. Remember to have your gloves on.
- Once the bowl is dried. Look for the two bolts on each side of the toilet. Sometimes they are covered with plastic caps. Pry the caps off with the screwdriver.
- Using the wrench, loosen the two nuts then remove them completely with your hand.
- If the bolts are corroded or just can’t come off, use the mini-hacksaw to cut the nuts off being careful not to cut the toilet body.
- Once the nuts are out, hold the toilet bowl with both hands and rock it a little to completely break the wax seal. Lift it off and place it on its side on the newspapers.
- To prevent sewer gases from coming up to the bathroom, plug off the drainpipe with the rag/towel.
- Remove the old wax ring and throw it away. Wax rings cannot be reused.
- Scrape off old wax sticking on the toilet flange and the toilet outlet with a putty knife.
- Inspect the status of the toilet flange. If it is worn out or broken it will need to be replaced. Replacing a toilet flange especially now with the toilet off is an easy task.
Step 3: Install New Wax Ring/ Gasket Seal
- To make the wax ring slide easily into the toilet outlet, a simple trick you should employ is to leave it outside in the sun for a while or dip in in warm water for a few minutes.
- If you had cut off the old bolts put news ones in place.
- Slide the wax into the toilet outlet gently being carefully not to deform it.
- If you decide to use the rubber gasket seal, install it on top of the flange. It has holes that go through the bolts to hold it in place.
Step 4: Install the Toilet
- Remove the rag/towel from the drainpipe.
- Lift the toilet above the toilet flange and lower it gently to align the bolts to the two holes on the toilet. If you can have someone to help you with the alignment, then call them in to help.
- Once the toilet has sat on the flange, hold it by the bowl with both hands, rock it and push it down gently to fully engage the wax seal.
- Put a washer and a nut on each bolt and tighten with the wrench.
- It is important to tighten the bolts alternatingly to keep the toilet level. Do not however tighten the bolts too much as this can crack the toilet bowl.
- If the bolts are too high above the nut, cut them off with a hacksaw.
- Install the plastic caps on the nuts. The caps are only for aesthetic purposes.
Step 5: Reconnect Toilet Water Supply.
- Connect the water supply line back to the toilet tank.
- Open the water shut off valve and let water fill the tank.
- Flush the tank several times and look for any leaks at the base of the toilet.
- Put the toilet tank lid back on.
If your toilet leaks when flushed and the wax ring was the problem, this repair should fix it. It is always advised that you fix it in good time to prevent the subfloor from rotting especially if it is wooden.
A toilet that leaks from the base when flushed can also bring foul smell. This is because urine or a mixture of urine and feces maybe leaking into your bathroom floor or in the subfloor.
To caulk or not to caulk the base of the toilet comes down to personal preference. If you decide to caulk around your toilet, leave a small opening at the back of the toilet. This way, if your toilet leaks, you will be able to notice the water on the floor.
2. How to Fix a Toilet that Leaks Between the Toilet Tank and Bowl When Flushed
When your toilet leaks when flushed between the toilet tank and the bowl, the culprit there is the toilet tank to bowl gasket which is also known as a spud washer. If you have a wobbly toilet tank, it also means that this gasket is not sealing properly and hence the water will leak when the toilet is flushed. The gasket could also be worn out
To fix a toilet that leaks when flushed between the tank and the bowl, you will need to replace the toilet tank to bowl gasket. A new toilet tank to bowl gasket comes with toilet tank bolts, metallic and rubber washers.
In order for you to replace the toilet tank to bowl gasket therefore, you will first need to remove the toilet tank.
How to Replace the Toilet Tank to Bowl Gasket.
As mentioned, to replace the toilet to bowl gasket you would need to first remove the toilet tank. Loose toilet bolts can be easily tightened using a wrench but corroded ones should be replaced.
Step 1: Drain the Toilet Tank
- To disconnect water to the toilet, turn off the shut off valve. This valve will be located on the rear wall of the toilet at the left-hand side.
- Turn the valve clockwise. If you have a push/pull valve pull it outwards.
Step 2: Empty the Toilet Tank
- Flush the toilet tank and hold down the flush handle to flush out as much water as possible.
- Use the sponge to mop out any remaining water in the tank and squeeze into the bucket
Step 3: Remove the toilet tank
- When you look inside the toilet tank, you will see the toilet tank bolts heads. They are tightened from underneath the toilet bowl with nuts.
- Using a wrench, loosen and remove the nuts and washers from underneath the toilet bowl.
- At this point, the tank is free and you will only need to lift it off and place it top of an old towel or rag.
- The toilet tank to bowl gasket is found on the outer part of the flush valve covering the entire flush valve nut. Simply slide it out.
- Push and remove the two bolts from the inside of the tank.
Step 4: Replace the Tank to Bowl Gasket
- Slide the new gasket where the old gasket was and ensure it covers the entire flush valve nut.
- Slide a metal wash into each bolt followed by rubber washers. Feed the bolts and washers into the bolt holes from the inside of the tank.
It is important to make sure that the washers which comes into contact with the body of the toilet are made of rubber. This will prevent the tank from cracking if you tighten it too much and also prevent the tank from leaking from the tank bolts.
Step 5: Install the Toilet Tank
- Lift the tank and guide the bolts through the holes on the toilet bowl. Make sure it is sitting pretty on the bowl.
- Put in a rubber washer, then a metallic one followed by a nut into each bolt. Use the wrench to tighten them alternatingly.
- Make sure the toilet flapper and the fill valve did not shift during this repair. If the did put the back in place.
Step 6: Reconnect the Toilet Water Supply
- Connect the water supply line back to the toilet tank. Do not use a wrench to tighten it.
- Open the shut off valve and let water fill the tank.
- Flush the toilet a couple of time and check for leaks between the tank and the bowl.
If a toilet leaks when flushed and the problem is the toilet tank to bowl gasket, this repair should fix it.
When you are satisfied that the toilet is not leaking anymore, put the toilet lid back on and clean your work area.
A toilet that leaks when flushed can be fixed easily at a low cost if you decide to do it yourself. If you however tried to fix it unsuccessfully, you can always call in a professional plumber.