What Causes Black Mold in Toilets?

Have you ever gone on vacation or away on business and come back home only to find black mold overtaking your toilets? It’s actually a very common occurrence and definitely nothing for you to get too upset about. Cleaning it out is a lot easier than you may think. So, what causes black mold in toilets?

The causes of black mold growing in your toilet are usually the result of leaving the water to sit for too long without being flushed, or if debris is left sitting in the water. Because mold tends to form in damp dark places and where it is humid, the toilet bowl and toilet tank are easy spots for this type of fungi to grow. It is important to note that there is a distinction between black mold and black stains and the approach to resolving each issue will differ.

However, black mold can be a menace, and you will definitely want to handle the situation with caution. This article will provide you with some easy steps to identifying black mold, how to handle it with caution, and how to clean it up quickly.

What Can Cause Black Mold in Toilet bowls?

Besides water or waste sitting still for long periods of time in the toilet bowl, mold infestation in your toilet can also occur if you have mold anywhere else in your bathroom. Mold can live in places like bathroom tiles, bathroom walls, shower curtains, or grout – basically, anywhere without proper ventilation and moist. Even having hard water can cause a mold problem due to mineral buildup, which can create the perfect place for mold spores to grow.

Mold spores can start just about anywhere and quickly spread throughout the room thanks to those same spores that can potentially make you sick.

Is Black Mold in the Toilet Dangerous?

Although you have probably heard horror stories regarding the extreme dangers of toxic black mold and how it can be detrimental to your health, it has never been proved that this type of mold is any more dangerous to humans than any other mold.

Those who suffer from allergies or have sinus issues or respiratory disease may want to be a lot more cautious when it comes to handling the mold, because mold airborne spores can aggravate these conditions.

What Are the Symptoms of Black Mold?

The majority of the symptoms you may experience if there is black mold in your home will be respiratory- and allergy-related. Some signs you have black mold in your house can include:

  • Coughing
  • Chest pain
  • Wheezing
  • Stuffy nose
  • Inflamed sinuses
  • Irritated eyes
  • Skin rashes
  • Sore throat
  • Headaches

How do I Get Rid of Black Mold in my Toilet?

There are multiple ways to get rid of black mold in your toilet. Depending on your preference, you can use strong cleaners sold in stores or you make your own formula with natural ingredients straight from your cupboard.

Chemicals and Cleaners

If you don’t mind suiting up, there are many different types of chemicals and cleaners on the market today that are excellent for getting rid of black mold.

  • BleachChlorine bleach is an extremely effective way to get rid of black mold and stains.
  • Toilet Bowl CleanersThese chemical cleaners can be found at any department store, and most of them are composed of chlorine bleach and hydrochloric acid.
  • Borax – Borax, also known as sodium borate, is a white mineral that has been used as a very effective cleaner for decades.
  • Dish soap Dish soap, especially Dawn, is a great way to eliminate mold and disinfect the areas where it grew.

Non-toxic Cleaners

  • VinegarThe acidity in vinegar is effective enough to clean dirt and grime while also strong enough to kill bacteria.
  • Baking sodaBaking soda is great for absorbing odors, and because it is an abrasive compound, it makes it good for scrubbing.
  • Hydrogen PeroxideBecause of the oxidizing properties of Hydrogen Peroxide, it is a great cleaning solution.
  • Tea tree oil Tea tree oil is an essential oil known for its antimicrobial properties.

Does Black Mold Wipe Off?

Yes, black mold will wipe right off. However, if it sat for a long time and was able to dry, it could stain and be extremely difficult to remove. You may need to apply a bleach solution to get rid of the discoloration in your toilet or any other location the mold has adhered to.

Does Bleach Kill Black Mold?

Bleach will kill black mold, but it needs to be diluted into a solution for your safety, and to make it easier to use. Many people still rely on bleach to effectively combat mold problems but going at it with a safer more natural approach is becoming more popular.

Steps to Removing Black Mold from Your Toilet

Here are some simple steps to follow if you are trying to rid your toilet of a mildew or black mold infestation.

  1. Empty the tank of the toilet.
  2. Pour a cup of bleach to one gallon of water solution into a spray bottle and spray the entire inside surface of the toilet tank.
  3. Allow the solution to set in.
  4. Scrub the entire area vigorously with a toilet brush until the mold is completely removed.
  5. Allow the tank to refill with water and give it a few flushes to clean itself out.

Related: How do you flush your toilet when the water is off?

Is it Safe to Remove Black Mold Yourself?

It is relatively safe to remove black mold yourself, especially if it is in a small area. Because of the mold’s airborne spores and the fumes and harsh reaction from chemicals, you should always wear gloves and a mask.

Related: What causes Red Rings in your Toilet bowl?


Finding black mold in your bathroom and in your toilet can be a startling discovery, and it may seem like a huge pain to deal with. In order to avoid these issues, look into mold prevention ideas like better ventilation, proper cleaning routines, and even add some vinegar to the tank weekly.

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