Mold in Toilet: Causes and Is It Dangerous?

Your relief zone could turn out to be a nightmare. The home toilet meant for managing human waste is one. When mold takes over, it can become a different experience.

You’ve probably been away for a while, and on getting back home, you lift your toilet lid and find a ring of mold in the bowl. While this irritates you, it could also discourage you from using the toilet at that moment. It can even lead to anxiety for those who already have the experience of mold growth.

You can find mold growing inside your toilet tank and in other areas around the toilet. At this point, you may be pondering on what to do. The first thing is to understand better mold in the toilet – what it is and how to deal with it.

What is toilet mold?

toilet mold

Toilet mold is a tiny particle of fungus growing inside your toilet. Mold produces spores, the microscopic cells that spread through the air, water, and insects. These spores act like seeds, forming new colonies of mold when they are in favorable conditions.

What causes mold growth in toilets?

mold in toilet causes and dangers

Every toilet has the perfect conditions for mold growth – moisture, nutrients (food), and a suitable place to grow.

Several reasons can make your toilet become a breeding ground for mold. If your toilet has been left unused for a couple of days, then don’t be surprised to see mold growing in it. Likewise, your toilet bowl and tank can grow mold because they are often dark and humid.

Nobody ever wants mold to grow in their toilet or sit there for a long time. The fungus can be a threat to your health, even if you’re in a good health condition. However, let’s see how mold thrives in each compartment of the toilet.

Mold in toilet bowl

mold in toilet bowl

When your toilet bowl is left unused for a couple of days, it can become a perfect environment for mold to grow. The stagnant water allows mold to thrive inside the bowl.

The lid also contributes to mold growth inside the bowl. When covered, it introduces darkness to the bowl. Then the fungus starts to grow in the absence of chlorophyll that comes from sunlight.

Reduced flushing also stops the passage of chlorination that helps destroy mold occurrence. The bowl thus becomes a perfect condition for mold to flourish.

Mold developing in the toilet bowl below the waterline can indicate that your tank is infested with mold. It could mean your water seal is broken, resulting in a leak from the water inlet.

Mold in toilet tank

mold in toilet tank

The mold that grows inside your toilet tank can be a serious problem. Due to persistent darkness and high humidity, the tank becomes a perfect place for mold to develop. If the tank is long-abandoned, mineral deposits can also build up around its walls as food for mold.

Mold in resin toilet seat

mold in resin toilet seat

Mold growing around the resin toilet seat is relatively uncommon and often caused by improper cleaning. This leaves the toilet seat in high humidity levels that allow fungi to crawl under it.

Mold around the toilet base

mold around toilet base

If your toilet is in good condition, it is seldom to find mold growing around its base. Leaks around the base usually trigger mold growth in this area. Then, the fungus begins to develop around the base, right above the leaks.

Mold under the toilet rim

mold under toilet rim

The shade and humidity in the underside of the toilet bowl are an ideal place for mold fungus to thrive. Even when using a disinfectant, you may still find it difficult to clean the brown or black discolorations under the rim. It could be that the tank is feeding mineral deposits or organisms into the bowl.

What type of mold can grow in toilets?

Different mold species can grow in every toilet, and your home toilet is not free from the attack. The types of mold listed below are liable to thrive in any toilet.

Black mold in the toilet

black mold in toilet

With a couple of different types of black mold, some varieties will only exist on porous surfaces. Hence, you won’t see them on the smooth surfaces of porcelain toilets.

Applying bleach will temporarily remove black mold from your toilet. You will discover that it will resurface after some time. The reason is that the spores reproducing this mold genus floats in the air and can replicate effortlessly in a damp, dark, closed toilet system.

You can easily spot black mold inside and under a toilet tank. Black discoloration shows the likeliness that black mold is growing in your toilet tank.

Pink mold in the toilet

pink mold in toilet

The commonly known “pink mold” is a pink stain that is not a mold or mildew. It is an airborne or waterborne bacteria called Serratia marcescen​s. It grows in a variety of colors, including bright orange and red.

Like mold, it thrives in warm, dark, wet conditions, such as toilets, shower, bathtub, or sink. It feeds on mineral deposits as well as shampoo or soap residue.

Red mold in the toilet

Red mold is one of the lesser-known mold types that exist, and it is also found growing in the toilet. While this mold is unsightly in its initial stage, it appears reddish as it grows.

Brown mold in the toilet

Brown mold is usually not common in many toilets. It takes the same appearance as brown stains rampant in the toilets of many people.

White mold in the toilet tank

White mold appears white in its early development and is typically unsightly in toilet tanks at this stage. But as it grows, it exhibits other colors and becomes noticeable. Most times, you will find it at the base and on the wall sides of the tank.

Green mold in the toilet bowl

The green discoloration in your toilet bowl is a sign of green mold and can be found on the sides of the bowl, above the water level. It can also appear as splotches of varied green hues and green-gray in the damp, dark toilet bowl.

Is mold in the toilet dangerous?

Mold starts to develop within 24 to 48 hours, and within this period, it’s still unsightly and harmless. But do you know when that visible mold starts to grow? Guess the simple answer is NO! So, it is crucial never to let any form of mold grow in and around your toilet because of the associated health risks.

The mold in your toilet is harmless if you are in good health. But if you’re allergic or sensitive to mold, exposure can lead to health problems such as respiratory distress. Exposure can also set off infections in the eyes, lungs, skin, and other organs. Those vulnerable to mold complications include babies, little children, older adults, and those with weak or compromised immune systems.

Typically, the black and green types of mold in your toilet are not dangerous if you detect and regulate them earlier using a professional mold remediation service. But if you or any member of your family experiences mold allergies, it could lead to diverse health problems.

Pink and brown types of mold are not as harmful as black mold, but you must get rid of them from your toilet with a sense of urgency. Your first contact with Serratia marcescens or brown mold is not harmful. However, they are linked with several ailments, including infections in open cuts and wounds, gastrointestinal issues, respiratory infections, and urinary tract infections.

People managing chronic illness and household pets are prone to pink mold. Ideally, you should get rid of this fungus immediately to prevent it from spreading and reduce the chances of infections.

Red mold is not dangerous for those in good health. But for those who have compromised immune systems, it poses health risks. White mold can be difficult to identify in the toilet bowl, and as such, you should not joke with it as it can trigger diverse health problems. You can suspect the presence of white mold when your long-abandoned toilet starts to make you sneeze, cough, or cause a runny nose.

What does mold in the toilet look like?

Have you ever noticed a black ring in your toilet bowl? That is exactly what mold in the toilet looks like. Whether it’s black, pink, red, brown, white, or green, mold usually forms a ring in the toilet. Sometimes, it appears grayish-black or black around the upper rim of the toilet bowl.

Look at the images below for more understanding of what could happen with the whole bathroom if mold growth keeps growing around the toilet:

what does mold in toilet look 1 what does mold in toilet look 2 what does mold in toilet look 3

How to identify mold in the toilet

Anxiety kills, don’t hurt yourself before mold strikes. You will probably exclaim on sighting brown discoloration in your toilet, but how will you justify the appearance as mold? Therefore, before you start to look for a way of eradicating that ugly appearance in your toilet rim, bowl, or tank, you first need to confirm that it is mold.

Mold testing is the only accurate method of confirming the presence of mold in your home. It helps over guesswork, and you will be sure you are dealing with mold. You should test your toilet and home early to prevent mold from spreading and causing harm to your family.

How to prevent mold growth in the toilet

For peace of mind over mold in your toilet, preventing the spores from spreading is the ideal thing you should do. The following tips will help you prevent mold growth in your toilet.

  • If your toilet has a window, always open it for ventilation or leave your exhaust fans to refresh the air after using the toilet.
  • Always flush and avoid leaving waste sitting in your toilet.
  • Do a thorough toilet cleaning at least once a week.
  • Add vinegar to your toilet tank two to three times a week.
  • Infrequently used toilets should be flushed at least every other day.

How to get rid of toilet mold

All forms of mold call for eradication. But it is ideal to understand the best method of eradicating mold in your toilet. The level of growth and spread will determine the best way to eliminate the fungus.

By now, you already know that mold spores are everywhere in the air. Eradicating that visible mold does not mean you have completely got rid of mold in your home. Therefore, cleaning mold with bleach and vinegar in your toilet will still leave the spores floating in the air.

Because of the potential health risks associated with mold, you need to remove it urgently. With that said, you need a certified mold remediation service to help you with the removal. However, be careful when hiring services that care only for your hard-earned money.

Hiring Mold Busters makes mold remediation in your toilet easy. We start by testing the air sample in your home because it is what you breathe in every day. Then, we will frankly tell you if what is in your toilet is mold or not. If it is, we are always available to help.

Call us today, and let’s discuss that mold issue in your home!

Frequently Asked Questions (FAQs)

Why is there mold in my toilet bowl?

The toilet bowl is a prime breeding ground for mold due to humidity and darkness. You will find mold growing in this area of your toilet if you have been away for a while and the toilet is left unused. Leaving waste in the bowl for a long time can also trigger mold growth.

How can I keep mold from growing in my toilet bowl?

Make sure it is always clean, flush whenever you use it, and ensure there’s a good source of ventilation in your toilet.

How to get rid of black mold under my toilet rim?

You can use a commercial toilet cleaner that contains disinfectants. However, such a cleaner will only get rid of black mold under your toilet rim. The spores still exist in the air.

Can I flush mold down the toilet?

Flushing mold down the toilet may or may not completely eradicate the mold. Even if it does, flushing does not eliminate the mold spores in the air of your home.

Can urine cause mold in the toilet?

Frequent mold in your toilet could be a sign that you have high levels of sugar in your urine, known as diabetes. While no scientific studies are supporting this claim, urine is likely to cause mold in the toilet. A consistent buildup of mold in your toilet could mean a member of your family could have poorly managed or undiagnosed diabetes.

Published: October 29, 2021 Updated: November 1, 2021

John Ward

Written by:

Account Executive
Mold Busters

Fact checked by:

CPI, CMI, CMR
Mold Busters

Charles Leduc