Mold In Toilet: Facts, Effects, and How to Remove It

Mold in the toilet is an unwelcoming sight to both you and your home visitors.

Now, mold does come in different manifestations and colors. But one thing that you’ll find common across all of them is the irritating smell that they draft.

If you’ve found mold in your toilet, then you’ve probably asked, how’s that possible?

Well, first off, mold will thrive anywhere that provides favorable conditions for its growth. Such conditions are humidity, warmth, and a viable food source. (In this case, water mineral deposits, and human waste).

If left unchecked, this problem could fester from your bathroom into other living spaces. In the end, you may face a problem especially if you have a mold allergy. [1]

That’s why in this guide today, you’ll get a chance to learn about mold in toilets, what brings them, and how to deal with a mold problem.

Ready? Let’s kick it off!

What is Mold?

Molds are a type of fungus that grow so much in dark, humid, and warm spaces. Most of the time, they will pick and grow in places left undisturbed for long durations.

Mold can grow on other surfaces in your bathroom too aside from a moist toilet bowl. This includes cardboard, paper (or paper products), wood, and ceiling tiles. All these surfaces act as a rich nutrient source for molds and will encourage their growth.

Other prone mold-supporting areas include wallpapers, paints, drywall, insulation materials, carpets, and fabrics.

When it comes to your bathroom, the most common type of mold that you’ll find is black mold. You may find some black molds more toxic than others. Although only a professional can help you distinguish between toxic and non-toxic black molds.

Once you’ve identified mold growing in your house, you must act fast to kill or remove it. A slow reaction to an infestation may cause the mold colony to spread to other places in your house.

And that’s one battle you don’t want to face…

Black Mold in Toilet

Before we proceed further, I must explain what may cause black mold in your toilet bowl.

Regularly, you will find them clustered under your toilet bowl’s rim all around. Their colony usually manifests as a black ring that may look like tar at first.

Mold in toilets grows as a result of a leakage, less frequent use, or when a toilet doesn’t receive proper cleaning.

Still, other times, mold growth may be a result of an infestation in the toilet tank. This infestation may spread down into the bowl when flushing as the spores move downwards.

You may also get a mold infestation in your toilet if the bathroom does not have enough ventilation. This is because mold reproduces through spores. These spores are very light and get distributed through the air.

So, if you don’t have proper airflow in your bathroom, then the mold spores are likely to settle in your toilet.

Note: You can still get an infestation in your toilet bowl but have a clean toilet tank at the same time.

Effects of Mold on Your Health

Effects of mold on your health

Different people react differently to different molds. But one thing that remains constant is that continued exposure to molds gives rise to various health effects.

Some of them, according to the CDC, include:

  • Asthma attacks
  • Pneumonia in extreme cases
  • Shortness of breath
  • Rashes
  • Headaches
  • Eyes, nose, throat, skin, and lungs irritation
  • Nausea

Exposure to these molds mostly happens either through physical contact or inhalation of their airborne spores.

Among the most vulnerable are people with an existing health problem, the extremely young/old, and a compromised immune system. [2]

That is why mold gets considered as a dangerous intruder that needs swift handling.

Mold Growing in The Tank Alone

Now, during your inspections, at times you may find mold growing in your toilet tank but not in the bowl.

How is that?

First off, this occurrence happens if the tank in question does not get used frequently. Over time, the inside of the tank will start getting warm. And if you remember, warmth is one of the conditions that support mold breeding.

As a result, the chlorine levels in the tank will reduce due to this inactivity. And as you know, the chlorine compound plays a big role in killing and preventing mold infestations.

In other cases, you may also find mold growth at the bottom of your toilet’s tank. This kind of mold growth indicates that there might be a problem with the tank’s washer. Two of my top bets are that you’ll find the washer either worn-out or broken.

Because of such a malfunction, water will leak onto the bottom of the tank as the seal now isn’t as effective. And with time, you’ll see mold start growing on the leak trail running beneath the tank.

If you have a broken-down washer, you have to replace it yourself or call in a plumbing service.

Mold Growing in Toilet Bowl Alone

On the other end, you can spot mold growing in your toilet bowl yet have no trace of it in the tank. This is highly common when your toilet bowl comes made from organic material.

In addition, it gets worse if you have hard water running into your tank. This is because hard water contains mineral compounds that support mold growth. If these minerals deposit in your toilet bowl, then you’ll likely face an infestation soon enough.

Also, other factors involve the pH of your urine and other waste deposited in the bowl.

To your surprise, there is an astounding toilet mold and diabetes connection. [3] This is when you or other users have an undertreated diabetes condition.

In that case, the body will find it difficult to process the glucose in your diet. Eventually, it will start excreting large amounts of unprocessed sugars from your body. This is through exhalation, sweating, and urinating.

In the end, the sugar deposits from your urine provide a rich source of food for molds hiding in your toilet bowl.

The other reason for constant infestations in your bowl may be because your tank or water pipes harbor mold. Here, the mold will just keep growing back each time you flush.

Home Remedies that Can Help You Remove Toilet Mold

You’ll get surprised that you may not have to buy a commercial mold remover to complete this task.

Chances are, if you make a quick sweep in your pantry, you’ll find them sitting on the shelves or drawers.

These include:

1. Vinegar

Vinegar helps a lot when cleaning out mild mold infestations. It makes a great solution if you mix it with baking soda and removes filthy molds in a blink.

2. Bleach

Bleach is one of the more readily available cleaning agents in our homes. And this is because of how badass they are when it comes to killing germs and removing stains.

Well, bleach, when used right, delivers one hell of a punch to molds!

3. Hydrogen peroxide

Aside from sterilizing and cleaning wounds, hydrogen peroxide can also kill molds.

So, reach into your medicine cabinet and get this secret weapon out for use!

What Will You Need?

Now, before you engage your gears, you need to have some important tools at your side.

Some are very important as they will protect you from taking damage from the mold. Some also cover your clothing to avoid taking damage from some of the cleaning agents (like bleach).

Therefore, aside from the 3 cleaning solutions mentioned above, you’ll also need:

  • Cleaning mask
  • Rubber gloves
  • Spray bottle
  • Toilet scrubber
  • Cleaning rug

Got all these checked? Great! Let’s get started…

Tip: Ensure that you have turned off all water supply into the bathroom. Turn off the bathroom water valve to do this. You can locate it behind your toilet. Afterward, flush and drain all the water from the tank and bowl for easy access and maneuvering.

How to Remove Mold from Your Toilet Tank

To clean mold from the toilet tank:

  1. Pour white vinegar (distilled) into the tank. Let there be a little water inside and let it sit for 2 hours.
  2. Flush a couple of times after the period elapses.
  3. If there are still signs of mold, then you can use a non-abrasive toilet brush to clean the lingering mold spots.
  4. Fill the tank again with water and then flush twice.
  5. Pour again a cup of vinegar into the tank and leave for 1 hour.
  6. Flush twice after the hour elapses. Your tank should go back to being as sparkling as before!

I advise that you don’t use bleach when cleaning the tank as it may corrode some parts.

Also, do not shy away from using your toilet brush when dealing with persistent black mold. Avoid metal or steel-wool toilet brushes as they can cause unwanted abrasions inside the tank.

How to Remove Mold from Your Toilet Bowl

There are 3 main methods that I suggest.

1. Vinegar and baking soda

Using vinegar and baking soda:

  1. Pour a cup of vinegar into the bowl and another cup inside the tank. This ensures that you deal with both the toilet tank and bowl at the same time.
  2. Sprinkle the baking soda inside your toilet. Ensure you spread it around the bowl’s rim and into the toilet bowl’s water.
  3. Leave it slightly for over an hour.
  4. After the time elapses, scrub the bowl using a toilet brush. Make use of the water/vinegar solution for the best results.
  5. Leave it again for another 15 minutes.
  6. Flush
  7. When done, do not let the toilet get used for a few hours.

Tip: Adding a cup of distilled white vinegar two times a week helps keep mold growth at bay.

2. Bleach

When using bleach:

  1. Mix 10 parts water and 1 part bleach in a spray bottle.
  2. Spray the solution all around your toilet bowl and pour some into the toilet water.
  3. Leave it for a few minutes then scrub using a non-abrasive toilet brush.
  4. Ensure that you scrub every crevice, including the hard-to-reach parts beneath the rim.
  5. Flush.
  6. Add a cup of bleach to your tank twice a week for the best results.

Note: Ensure that you dilute the bleach well enough to prevent your toilet bowl from turning yellow.

3. Hydrogen peroxide

When using hydrogen peroxide:

  1. Pour 1 cup of hydrogen peroxide inside the toilet bowl.
  2. Thoroughly scrub the entire surface of the bowl using a non-abrasive toilet brush.
  3. Leave the peroxide in for about 15 minutes before flushing. You might see some bubbles fizzing as a result of the hydrogen peroxide killing bacteria.
  4. Flush the toilet bowl twice and repeat this exercise twice a week to prevent future mold invasion.

Other Ways that Can Remove Mold from Your Toilet

Aside from the above methods, there are also other ways to deal with mold in your toilet. It involves:

Using a handheld steam cleaner

So, a couple of my friends reported great success using their handheld steam cleaners to kill mold. So if I figured, why not share?

To do this:

  1. Using an angle attachment, place the nozzle under the bowl’s rim and steam. Ensure that you have high pressure and spread this all over the bowl.
  2. You can direct the steam on the hinges and seat edges to remove rust (if any).
  3. Wash the loosened dirt into the bowl using a vinegar-filled spray bottle.
  4. Flush.
  5. Wipe away any residing water using a clean cloth.

Note: You can repeat this process until you get the results that you want.

How to Avoid Future Mold Growth in Your Toilet

How to avoid future mold growth in your toilet

To avoid future mold infestation in your toilet, these are some things you’ll have to do:

  1. Always open your bathroom window when showering.
  2. Always turn on your exhaust fans during a shower and leave them on for 30 minutes when done.
  3. Consider installing a dehumidifier if your bathroom has higher humidity levels. Leave it on for an hour after a shower.
  4. Always flush after using the toilet.
  5. Scrub your toilet at least once a week using a brush and vinegar/bleach/peroxide solution.
  6. Always flush less frequently used toilets at least once a week to prevent mold build-up.
  7. Take care of any bathroom leak as soon as possible.


Above everything else, we have seen that it’s very important to keep your toilet mold-free. The top reason is for good health purposes.

While some come off as more dangerous than others, it’s in your best interest to act swiftly on any mold infestation. Just to be on the right side of the tracks.

Again, if you have persistent mold growing back shortly after you clean, seek the services of a professional.

I hope this guide helped you out.


Now go kick some mold butt!

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