Why Is Mold Growing in My Shower: Engineer’s View


Noticing mold in your shower can be a bother because it tends to affect the appearance of your bathroom. I hated the fact that I had mold growing in my shower even though I had been washing down the shower floor and walls after each shower. To rid my shower of mold, I had to learn the first step for getting rid of mold, which is to understand why it is showing up in the first place.

Why Is Mold Growing in My Shower? Mold is growing in your shower due to a combination of numerous factors like a build-up of moisture, insufficient ventilation, and low temperatures. This environment increases the humidity level that is the perfect scenario for the spread of mold spores.

Hugo Hens, who is a Building Engineer that has a PhD in Civil Engineering, wrote a study on the presence of mold in homes. He mentioned that humidity and condensation on walls can cause the growth of mold. Also, a ventilation problem is the most common factor in the cases that they had analyzed. Plus, the fact that many people keep their bathrooms cool to save on their heating bill. These two key factors increase the level of humidity.

If you want to decrease the humidity in your shower, you can purchase a dehumidifier. One excellent product is the Frigidaire 22 Pint Capacity Dehumidifier, and it is available on Amazon. To kickstart your mold-free experience, order yours now.

Types of Molds Found in a Home

Mold NameLocation
AlternariaWindow frames, carpets, air conditioners, and wallpaper.
StachybotrysWet surfaces like basements, bathrooms, carpets, and laundry rooms.
CladosporiumSpaces with limited ventilation and sunlight.
TrichodermaWooden furniture, carpets, wooden floors, and wallpaper.
FusariumIn plant fields and gardens (on the soil).

Why Is My Shower Getting Black Mold?

Your shower is getting black mold due to the excessive humidity in the area. Other common causes of black mold in showers are darkness and water leaks. If any of the situations are present in your shower, mold spores will thrive there.

Black mold can grow in your shower if the humidity levels there are excessive. Especially if you have HVAC systems installed, humidity levels in your home fluctuate in the different rooms.

Your bathroom may get excessively humid causing black mold. Therefore, it is often advised to keep the humidity levels around 60% and take steps to reduce high humidity, such as purchasing a dehumidifier.

Dark shower areas are thriving spaces for black mold, otherwise known as Stachybotrys chartarum. Unlike other rooms in your house, the lights in the bathroom are mostly turned off when the place is not in use.

Worse still, some houses have naturally dark shower areas because of the building structure or recent ceiling leaks. This could be another reason your shower is getting black mold.

A lot of times, people treat tiny leaks as nothing, without knowing that this condition can cause mold growth. Water leaks can lead to black mold in the shower because bathrooms have the perfect growing conditions for mold: oxygen, warmth, and moisture.

The drywall serves as a food source and the high moisture levels make the mold spread quickly. Clogged drains and leaks from faucets are all major sources of black mold growth.

Harsh weather conditions and burst pipes are some situations that can cause water leaks, which then lead to black mold. These leaks easily penetrate walls and mold grows there.

Your shower may also be getting black mold because the area is poorly insulated. Tiny holes and cracks draw moisture in. The humidity and moisture levels in a space with improper insulation are often higher and both factors promote mold growth. 

What Are the Signs of Mold in the Bathroom?

Some common signs of mold in the bathroom include visible mold, a musty smell, or discoloration of bathroom walls. Another indicator is when the bathroom floor feels soft or damp when stepped on and when there are patches of dirt and insect infestation.

Mold spores are tiny so you may not notice them at first. But they reproduce rapidly and then the growth is visible. Look towards areas like behind the WC or around faucets for visible mold spores.

These cold surfaces have elevated levels of moisture, making them suitable areas for mold to latch onto. Aside from black, mold can take on other appearances like grey, brown, or even blue. 

It’s easy to notice mold in the bathroom when the growth is visible but sometimes, all you get is an unusual odor. Your bathroom begins to smell musty or rancid. What is simply happening is that the mold spores are decomposing materials in the shower which releases the unpleasant smell.

Exposure to this smell can be dangerous, especially for people dealing with respiratory allergies. 

Low-quality painting or poor insulation can cause wall damage but so can mold growth. Discoloration or falling paint can be a sign of mold infestation. The mold might be living inside the walls and causing damage to these materials.

Gaps in caulk usually mean mold spores growing behind the wall and filling the spaces. Poor insulation gives room for moisture to seep in, causing mold colonies or damage to the wall.

Black mold can show up as dirt particles when in fact it is mold spores. You may dismiss black particles between your shower tiles as dirt only to clean them and find the area having the same appearance within a short while. Similarly, you shouldn’t overlook every case of insect infestation. Pests love moist woods which may have been degraded by mold.

How Dangerous Is Black Mold in the Bathroom?

Black mold in the bathroom can be dangerous if ingested since it contains toxic chemicals called mycotoxins. You are also likely to be affected by black mold if you already experience allergies or hypersensitivities.

Several claims that black mold can cause serious illnesses to have been considered incomplete since they are hardly backed by sufficient evidence. However, mold exposure is associated with symptoms like fatigue, lack of focus, and headaches. The term “toxic mold syndrome” is often used to describe these symptoms.

Black mold certainly looks unpleasant and that is enough reason to have concerns about it. But there is little proof to support the claim that it causes fatal illnesses.

However, mold can lead to severe problems for people allergic to it. Medical professionals diagnose mold allergies by carrying out a skin prick and blood test. The substance is applied to the skin to determine if you are indeed allergic to mold. Afterward, you undergo an allergy blood test. Some people may be allergic to other types of molds but not black mold.

Exposure to black mold in the bathroom when you have a mold allergy can lead to skin irritation or breathing problems. Sometimes, even people without mold allergies can experience these symptoms. The effects may be more serious if you have a weak immune system or are prone to respiratory diseases.

If you’re asthmatic, inhaling bathroom mold can trigger an attack or make you feel like you have come down with a cold. Certain types of molds may have even more dangerous effects like causing lung infections.

Mycotoxins which come from black mold can come into the body through the skin, airways, or intestines. These chemicals have been linked to health issues like cancer, lung problems, and diseases affecting the digestive system.

How Do I Stop Mold Growing in My Shower?

The best way to stop mold from growing in your shower is to reduce moisture levels. Other steps like keeping the bathroom clean and providing ventilation can help prevent mold growth. Seeking professional help from mold remediation companies also helps if you would rather not handle the task.

Preventing mold growth is often easier than eliminating it. However, if mold is already growing in your shower, controlling moisture helps to get rid of it. One way to increase ventilation in your shower is by running the exhaust fan while showering and afterward. This helps keep the bathroom dry and prevents mold from growing.

Natural ventilation methods like keeping the bathroom windows open allow fresh air into your shower to keep it dry. You can shut the door while bathing but open it later to disperse moisture. Similarly, leave the shower curtain open so the moisture evaporates. Remember that moisture promotes mold; avoid creating such an enabling environment.

Keeping your bathroom clean is another effective practice to eliminate mold growth. When you clean regularly, you get rid of dust and other nutrient sources that mold needs. Incorporate a weekly cleaning schedule where you focus on disinfecting the bathtub, sink, and toilet. Do not forget the mirrors and windows when cleaning.

Most people successfully eradicate mold in their shower and then stop paying attention after a while. The more vigilant you are, the quicker you will notice mold spores when they begin to appear. Mold comes in several colors so keep an eye out for all kinds.

Working with professionals may be a more ideal solution when dealing with copious amounts of mold. There are often concerns about the lack of standards set for mold inspectors but some of them do an impressive job when testing for mold. These experts come in handy when regular mold removers and homemade remedies prove ineffective.

Home Remedies for Mold Removal

VinegarSpray undiluted white vinegar on the affected area. After sitting for at least an hour, wipe off the mold.
Hydrogen PeroxideCover the moldy area with a 3% hydrogen peroxide solution. Clean it off after about 10 minutes.
Baking SodaSpray a baking soda solution on the mold, scrub off with a brush, and rinse with water.
Tea Tree OilApply a diluted solution of tea tree oil to the mold and let it soak for at least an hour before cleaning it off.

What Are the Signs of Mold Sickness?

The most common signs of mold illness are coughing, wheezing, itchy eyes, and nasal irritation. Symptoms often vary depending on the level of exposure and other factors. Individuals with mold allergies are more likely to experience serious side effects after inhaling mold.

These signs can show up soon after exposure or be delayed. In some people, mold sickness comes with signs. People with allergies are more likely to get the symptoms of mold sickness quicker.

Their immune system reacts quickly to allergens and may instantly consider mold spores dangerous. Inhaling substantial amounts of mold can cause symptoms to develop quickly while exposure for a short while might present no symptoms.

Allergy-like signs of mold sickness include a runny nose, itchy skin, and shortness of breath. Inflammation as a symptom of mold sickness is caused by mycotoxins which create broader symptoms including vertigo and hormone imbalances. Like other allergies, the symptoms vary and may increase during certain times of the year.

Children and pregnant people often show signs of mold sickness after exposure. Older people and those with existing diseases that weaken their immune systems are also at risk of developing symptoms quickly.

Black mold particularly is associated with skin swelling and irritation that causes discomfort. In severe cases, mold sickness can manifest as pneumonia, sinusitis, or even infections that affect the brain. Surgical intervention is often needed to treat these sinus infections.

Even with these signs, mold sickness can be difficult to diagnose for many reasons:

  • Studies establishing the connection between mycotoxins and human diseases are limited.
  • There are no approved standards for mold testing.
  • Symptoms of mold sickness vary in patients.
  • Some people show no symptoms of mold sickness even after exposure to mycotoxins.

Why Does Bathroom Mold Keep Coming Back?

Bathroom mold keeps coming back after removal mostly because you have not eliminated the moisture source. So long as its food and moisture source are intact, bathroom mold recurs. This means you must tackle mold from its source to eliminate it.

Even after a reputable mold remediation company has removed mold in your bathroom, mold can still come back if you don’t take active steps against it. It all sums up to cutting its food supply and making your bathroom inhabitable from mold. The substance reproduces rapidly so regrowth is possible just a few days after removal.

Home treatments have their place in mold elimination but sometimes, they are not the most effective to eradicate mold forever. You need to take other steps to prevent the problem from recurring. 

Mold spores attach themselves to moist areas so if you clean the mold in your bathroom without improving ventilation there, mold growth persists. The solution here would be to cut off moisture sources like leaking pipes. Running a fan in the bathroom while showering also increases ventilation.

Sometimes, mold penetrates deeply into shower curtains and mats. These items may not be completely free from mold even after you wipe them with bleach. After a while, the bathroom mold growth accelerates.

Mold Questions:

If you have mold in the shower, will a dehumidifier kill mold or not.

To prevent mold from coming back, you may need to replace items in your shower that constantly house mold. This is often a more efficient way to control their spread.

Bathroom mold can be gone for good if you tackle it following the right approach. Find out the root cause of mold growth, reduce the moisture levels and monitor commonly affected areas even after mold removal.

Aron Blake

I am the lead copywriter on Homezesty and the Webmaster. I have a lot of experience in home renovations and the creation of style. I enjoy writing and sharing my tips on how to create the best living environment. My Linkedin Profile, My Twitter Account

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