Why Mushrooms Grow in Bathrooms and How To Fix It

Mushrooms growing in the bathroom can be an unsightly, annoying problem for sure, but did you know that besides being unpleasant to look at, this bathroom fungus can also be hazardous to your health? 

Mushrooms are a type of mould that grows in warm, humid conditions. Your bathroom presents the perfect mould and mushroom growth environment, especially in areas where moisture collects. You may find mushrooms growing on your bathroom walls, floor, and even the ceiling, or even mould growing inside your toilet water tank. The presence of fungi, however, is indicative of a major moisture problem that needs attention. 

Mushrooms growing in bathrooms are a common issue, so if you are battling the fungi in your bathroom, you’re not alone. The good news is that you can get rid of the mushrooms growing in your bathroom. You can eradicate the offending growth using a little know-how and the right cleaning products. 

In the paragraphs that follow, I will fill you in on everything you need to know about mushroom growth in your bathroom and how you can get rid of it for good. 

Mushroom Growing in Bathroom

As with any fungal growth, conditions must be just right for the spores to develop into mushrooms. In the case of mushrooms growing in the bathroom, there must be high heat, plenty of moisture, and low light conditions for two of the single-celled spores to combine and begin growing. 

Mould and mushroom spores can stick to just about anything, and they are so lightweight that they can be carried from place to place on the lightest of breezes. As a result, you may find mould, mildew, and/or mushrooms growing in seemingly impossible places in your bathroom. 

 Mushrooms Grow in Bathroom
Mushrooms growing on bathroom ceiling

Bathroom Ceiling

Your bathroom ceiling is a prime location for mushroom growth. This is because heat and humidity rise while you’re bathing, making the ceiling a moist and inviting place for spores to do their thing. Mushrooms and other fungi like to make their homes in corners and crevices, so if you notice any green or black buildup in corners where walls meet the ceiling, you likely have a bathroom fungus problem. 


The shower presents mushrooms with the ideal environment for growth for obvious reasons. The excess moisture and humidity that is regularly present in the shower is the perfect place for mushrooms to set up shop. You may find mushrooms growing just about anywhere inside your shower stall as the constant moisture is an open invitation for mushroom spores. 

Bathroom Walls

And finally, no surface is exempt from possible mushroom growth in the bathroom. Although your bathroom walls are vertical and likely don’t hold moisture for very long after you shower, it is still possible for mushrooms to take hold, especially if there is a leak somewhere behind the wall. If you find mushrooms growing on your bathroom walls and the room isn’t particularly damp, there may be a leak behind the wall that you’re unaware of. 

What Causes Fungus To Grow In Bathrooms

For mushrooms and other single-celled organisms to grow, there need to be three things: heat, moisture, and low light. Bathrooms typically meet all three of these requirements, making mushroom growth a common problem. 

Mushrooms need moisture to thrive. It provides a nutrition source for fungi. They also need heat – 77-86 degrees is ideal. They will not grow in temperatures below 40 degrees. Lastly, low-light situations tend to create the kind of environment mushrooms love. While insufficient lighting isn’t directly related to mushroom growth, dark areas are usually damp areas, which invites fungus growth. With that said the dark, damp corners of your bathroom make for great mushroom growth. 

At this point, you may be wondering how you’re supposed to get rid of and prevent mushrooms from growing in your bathroom when the sheer nature of the room is always warm, moist, and dimly lit. It may seem like an exercise in futility, but rest assured, there is a way to remedy the problem. Keep reading!

Are Mushrooms Growing in Bathrooms Dangerous

Before we get to the removal and prevention of mushrooms growing in the bathroom, I want to let you know of the risks of allowing such fungi to continue growing in your home. The little buggers may seem harmless enough, and while they aren’t especially deadly, they do present health concerns. 

For example, although the mushrooms that grow in bathrooms aren’t poisonous, you shouldn’t eat them. Poisonous mushrooms aren’t likely to grow inside your home but eating them isn’t a good idea because the conditions that cause mushrooms to thrive in the bathroom are the same conditions that black mould and mildew thrive in, which can be dangerous to your health. 

Suppose you have mushrooms growing in your bathroom. In that case, it is an indication that there is a serious moisture problem that might lead to the growth of black mould, which can cause serious allergic reactions and respiratory issues. Although mushrooms themselves present little to no health threat, the accompanying threat of black mould makes getting rid of these intruders a must-do sooner rather than later. 

Removing Mushrooms From Your Bathroom

Removing mushrooms from bathroom walls, showers, or ceilings is an easy process, but you will probably need to repeat the process more than once to fully eradicate the fungi. Before beginning, be sure to don protective gear such as gloves, face masks, and safety glasses to avoid contact with any wayward spores as you clean. Remember, where there are mushrooms, there may be black mould, so don’t skip the protective gear. 

  1. Physically remove any mushrooms that are already growing. Simply pick them off the surface like you’re picking flowers. 
  2. In a spray bottle, combine one part bleach with three parts water. 
  3. Spray the affected area(s) with the bleach solution and allow it to dry completely. 
  4. Apply more bleach solution and scrub the area using a brush or scouring sponge. 
  5. Rinse the area and dry it using an old towel. 

If you don’t want to use bleach, you can make a natural fungus cleaner by mixing one teaspoon of baking soda with hot water in a spray bottle. Follow the steps above to get rid of mushroom growth in your bathroom. 

Note: If the bleach solution doesn’t keep mushrooms from growing again, you may need to purchase a fungicide to kill off any remaining spores so the fungi can’t grow again. You can find fungicides at any home improvement store. As I said earlier, you may need to repeat this process multiple times to completely get rid of any mushrooms growing in your bathroom. 

Preventing Bathroom Fungus

Now that you know how to get rid of mushroom growth in your bathroom, let’s talk about some of the things you can do to prevent it from happening again. While it’s almost impossible to keep any bathroom completely dry, you can take steps to keep it drier. 

Since mushrooms and other fungi can’t survive without moisture and heat, make sure your bathroom has adequate ventilation. You can install an exhaust fan that you can turn on during and after your shower to remove excess moisture and heat, or you can open the windows and doors in and around the bathroom to allow excess moisture to escape. 

Next, do your best to keep all bathroom surfaces as dry as possible. Don’t allow bathmats or damp towels to sit on the floor. Hang them up to dry after each use. 

Finally, if you think there may be a water leak in your bathroom, get it repaired immediately. If the leak is severe or has been happening for quite some time, you may need to replace flooring or drywall to fully remove the risk of fungi growth. Check the bolts and seal around your toilet as well to make sure no excess moisture is seeping in from there. Any extra moisture that you can stop from entering your bathroom will help prevent future mould and mushroom growth. 

The last bit of advice I have for you is this: clean your bathroom regularly. Not only will this help keep mould and mushroom growth to a minimum, but it will also enable you to identify any problem areas that need special attention or repair. 

Mushrooms growing in bathrooms is a common problem that is (relatively) easy to fix. With the knowledge, I’ve given above, and a little elbow grease, you should be able to eradicate the invasion and prevent it from happening again. Mushroom growth isn’t a health concern in and of itself, but where there are mushrooms, there is likely toxic mould, so don’t ignore the issue.

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Having renovated two homes and completed countless repairs, it was time to share this experience with the world. From repairing kitchen appliances to remodeling entire homes, my 30 years of experience will hopefully help you on your journey to a beautiful and functional home