How To Get Rid Of Mold In The Bathroom

By: Licensed Mold Assessor Brad Fishbein

August 7, 2018

You will have to agree that one of the most frustrating things about cleaning your bathroom.... the build-up of a black staining around the grout.

You know, this stuff:

Is that mold?

Is it mildew?

Truth is, for you, it really doesn’t matter what it is, you just want it out of your bathroom, right?

Well, good news:

After reading this article, you are going to be able to create a completely “black stuff” proof bathroom! You will know exactly how to get rid of mold in the bathroom and keep it out!

In This Article You Will Learn:

  • What Causes Mold In The Bathroom
  • Is Mold In The Bathroom Dangerous
  • How To Remove Mold In The Bathroom
  • How To Prevent Mold In The Bathroom

What Causes Mold To Grow In The Bathroom

In order to properly explain mold in the bathroom, we are going to classify it into two separate mold types:

  • Normal Mold
  • Problem Mold

Normal Mold

Normal Mold

Normal mold in the bathroom is exactly that:


This type of mold is very common and can happen in just about any bathroom, in any home.

Does it signal that your home is dirty or that your house is full of mold?

Absolutely not!

Regardless of how much you may have paid for your beautiful shower, your super high-tech toilet that practically wipes your butt for you, or your fancy vanity, this type of mold can present itself in the bathroom.

So this normal type of mold, here’s where it will generally appear:

  • On the silicone around the edge of the shower
  • On the grout in between tiles in the shower
  • On the ceiling of the shower
  • Bathroom walls
  • On the floor grout behind the toilet

This type of mold will generally not have enough moisture to colonize and in most cases can be cleaned right off the surface. It will generally appear in spots.

As far as color…

mold on wall paper

It can range from yellow in color to black although I must say that if you have wallpaper on the walls (which is such a terrible idea in bathrooms) it can appear in other colors such as brown or red due to the material.

In the shower, it will just be black.

Normal bathroom mold will be due to moisture but is not related to a leak.

What Causes Normal Mold In Bathrooms?

Normal mold in bathrooms can be caused by multiple issues.

I mean, it kind of makes sense…

…Think about how much water and humidity is going on in a bathroom.

You ever notice when the mirrors fog up when you take a shower?

Well, that is due to the condensation of hot water vapor in the shower touching the cooler mirror.

If you feel the walls after the shower you will also generally feel some condensation on your fingers.

Then you have water sitting in a bowl and water running in the sink. There is just a ton of water in the bathroom period!

The Number One Cause Of Normal Bathroom Mold

The number one cause of normal bathroom mold is improper ventilation. Most bathrooms in newer homes have a ventilation fan in the bathroom. Heck, even most older homes do as well.

bathroom ventilation fan

The problem is:

Many people don’t use it, or it is not working very well.

You see, the builder of the home didn’t just install that fan for show. It serves a purpose (not just when you are using the toilet!) and allows the bathroom to be vented properly. So if you are taking a shower, make sure that fan is on and if it is not working properly, get it fixed!

Other Causes

Other causes of normal bathroom mold is usually due to building activity also.

If you are lazy and leave a wet towel in the corner of a bathroom, guess what can start growing on it and the wall it is leaning on?

What about when you get out of the shower drenched and you are standing on that porous mat?

Yup, mold can start to grow on anything porous, even clothes!

Just be mindful and you won’t have to worry.

Problem Mold

Problem mold in a bathroom is due to some type of leak.

And no…

I’m not talking about water falling off you when you are stepping out of the shower like in the example above.

The type of leak I am speaking of is the same type of leak that can happen in pretty much any other part of the home.

Some examples are:

  • Roof leaks
  • Leaks under the sink
  • Window leaks


Obviously, you can also have toilet and shower leaks as well.

These type of leaks, if left unattended, can lead to microbial growth and actively growing mold colonies.

Problem mold in bathrooms usually needs to be professionally remediated by a licensed mold professional.

Two Problems With The Shower That Is Usually Ignored

shower grout deteriorated

Two very common issues with the shower that are either ignored or hard detect are:

  • Water getting behind deteriorated tile grout
  • A leak in the shower pan

Water getting behind deteriorated shower grout usually won’t be catastrophic. The reason for that is the material behind the shower tiles will usually be some type of moisture-resistant board. That doesn’t mean that excessive water over a period of time can’t cause damage, especially if there is a room with drywall behind this area.

Leaks in the shower pan can usually not be detected unless the shower is on the 2nd floor. At that point, you will start to see some staining or water starting to come through the ceiling. In some cases, there won’t be a problem if the shower pan is leaking on the first floor, but I’m not putting a guarantee on it! You would have to talk to a plumber of some sort if you wanted to know if a first-floor shower pan is leaking.

Is Mold In The Bathroom Dangerous?

Well, it all depends…

…Do you have Normal Bathroom Mold or Problem Bathroom Mold?

Normal bathroom mold is generally harmless.

As stated earlier, this will not usually signal active mold growth.

The two species of “normal mold” in the bathroom that will generally be found will be:

  • Penicillium/Aspergillus
  • Cladosporium

These two types of mold species will usually not cause any type of health effects to you unless they are either present in large amounts or you have a particular type of allergy to these mold spores.


Problem mold can lead to health issues.

The reason for this…

… The actively growing mold spores can possibly be airborne. This means it will start to affect the air your breath.

This type of mold cannot just be wiped clean and in all likely hood, the building material is water damaged so bad that you will have to actually remove it.

While the type of mold present, may also be Penicillium/Aspergillus and Cladosporium, they will likely be present in higher amounts and may be growing inside of the walls as well.

Yes, black toxic mold may also be included when problem mold is growing in a bathroom.

Because most of us shower with hot water, there is really such a good opportunity for black mold to grow when there is some kind of leak present. If you are unsure if you have problem mold or normal mold in your bathroom, you should have a mold inspection completed.

How To Remove Mold In The Bathroom

Now, this is probably what you have been waiting for…

Getting rid of the mold in your bathroom!

… And I will not disappoint because you are about to get two completely awesome and effective ways to remove mold in your potty room!

Keep in mind that we will be talking about removing normal bathroom mold. If you have problem bathroom mold which is due to a leak, you should always have it professionally removed.

When you think of bathroom mold, you are likely thinking about mold that forms around the edges of the shower which is the most common area. So let’s get rid of it!

The Toothbrush Moldy Shower Cleaning Method

moldy toothbrush method


I’m guessing you may have this one figured out by the name.

It involves a toothbrush!

Basically, you would take white distilled vinegar and you would dip the toothbrush in.

Start to scrub the affected area with minimal pressure for about 2 minutes. You don’t want to scrub too hard as it can cause damage to the grout. Make sure you are wearing rubber gloves when doing this.

Let it sit there for about an hour, and then wash it off with warm water. It should improve the mold on the grout, but if it is not up to your standards, repeat the process once again.

How To Prevent Mold From Coming Back In The Bathroom

Most of these are laid out above, but I am going to organize them for you so you can follow them ensuring that you are doing your absolute best to not allow mold to grow back once you have removed it.

Preventing Problem Mold

Obviously, for problem mold, you want to make sure that you are on the lookout for leaks. Regularly check for leaks around under the sink and around the toilet. You can do this by getting a hold of a moisture meter. Here is a brief overview of how to use a moisture meter:

If you notice any kind of leaks, you should contact a plumber right away to correct the issue. Leaks are going to happen, it’s how you react to it which will determine if mold will grow or not. If you let the area leak for an extended period of time, you can sure as heck expect to have a mold issue!

Preventing Normal Mold

Preventing normal mold will require more attention than just periodically checking under your sink.

First things first:


I touched on this earlier but if you do not have a fan here is a rule of thumb to go by when determining the size of your ventilation fan:

If the fans aren’t clearing out most of the moisture in your bathrooms after five to 10 minutes, your fans may not be moving enough air. Fans are certified by the volume (cfm, or cubic feet per minute) of air “exhausted” out of the room. To find the recommended fan capacity for your bathroom, simply multiply the bathroom square footage by 1.1 (assuming an 8-ft. ceiling; for a 9-ft. ceiling, multiply by 1.5).


This will drastically prevent any kind of surface mold growing in the bathroom if you use this fan.

One thing to ensure is that the fan is vented to the exterior and not directly into the attic which can lead to issues with moisture as well!

Make Sure Your Shower Curtain Is In Place Or Shower Doors Are Completely Sealed

Your shower curtains and shower doors have one purpose:

Keep water in the shower!


Actually, now that I think of it, it actually has two purposes.

The other is so people can’t see you naked!

Ensuring that the shower curtain and shower door are properly doing its job will ensure that your bathroom floor outside of your shower will not be completely flooded. Keeping the bathroom as dry as possible is key.

singing in the shower

I get it, you live to sing and party naked in the bathroom, just keep the water in the tub!

Change Your Shower Curtain

If you have a shower curtain than you know it can get pretty gross over a period of time. Yes, you can try to clean it.

But here’s the thing:

You will have to change the inside liner two or three times a year. Mold can start to grow on it making a pretty ugly site!

Keep The Bathroom Door Open If You Don’t Have An HVAC Register Present

Most homes are made with an HVAC register in the bathroom.


If your home is not, you should try to leave the door open as much as possible to allow proper air exchange. This will pull some of the humidity out of the bathroom.

Clean The Bathroom Regularly

If you stay on top of the cleaning in your bathroom, you will never have to worry about cleaning mold.


Maybe you are lazy or you can’t afford a cleaning person.

I get it! I am kind of lazy myself.

Technology is a cool thing though and you can actually buy bathroom cleaners that you spray and just walk away. If you are too lazy for that, there’s nothing I can do for you!

Got Any Tips?

This is what works for me, but if you have any other DIY tips, please share!

Meet the author: Brad Fishbein is an ACAC council-certified Microbial Investigator. In the fall of 2012, he became a Licensed Mold Assessor in the State of Florida through the Department of Business & Professional Regulation. Brad has helped homeowners with over 5,000 successfully completed Mold Inspections since 2009.

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