How To Get Rid Of Mold In Shower Caulk

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Having a mold problem in your bathroom? While shower caulk is waterproof, it isn't mold-proof. Sooner or later, mold spores are going to make a home out of the moist environment that is your shower or tub.

Once mold attacks shower caulk or grout, it can be particularly hard to remove. But thankfully, the task to remove mold from shower surfaces is not an impossible one with the right cleaning method. Let's go over what you can do to clean shower caulk and kill mold.

First Things First: Where is the Mold Growing?

If mold is growing on top of your caulking or grout, consider yourself lucky. Why? Because mold can actually form inside or under grout or caulk. The reason this can happen is because over time, your caulking may crack. All it takes is a tiny fissure for mold to get underneath.

To figure out what you are dealing with, soak a few cotton balls in bleach, and press them onto the affected area. If you see the mold go away right away, it is probably superficial.

But if 30 or 40 seconds go by and you can still see some mold, then it is inside the caulk. That is bad news, but you can still stop mold, even when it penetrates your caulk.

What You Need to Remove Mold from Shower Caulk

Exactly what you need to remove mold from shower caulk depends on your exact situation. But for the sake of this post, we are going to assume you need to remove mold growth from under your caulk. We also will be focusing on shower caulking specifically, not grout.

You may already have most of the materials and tools you require on hand. If not, you can get everything on this list from your local hardware store.

Tools and Materials

  • Bleach
  • Caulk remover
  • Utility knife
  • Putty knife
  • Water
  • Grout sealer
  • Caulk

How to Remove Mold from Shower Caulk Step by Step

If the mold problem only affected the top of the caulk, just the diagnosis process we described using the bleach should have been sufficient to kill it. But if it is under your caulk, you are going to need to start by removing the caulk itself.

Step 1

Apply a caulk remover of your choice to the old caulk you want to get rid of. You will need to wait while the caulk removal product softens your caulk. The more time you give it, the easier it will be for you to remove the caulk. About 4 hours is idea.

Step 2

Use a utility knife to scrape away the caulk. If you prefer, you can invest in a caulk removal tool designed specifically for this purpose.

Step 3

Still some residue left over once the caulk is gone? You can use a putty knife to get rid of what is left. If you do not have one, a toothbrush is often sufficient.

Step 4

Look for the mold. Do you see it? You may be able to proceed to the next step. But if you do not, you need to figure out its source. Sometimes, unfortunately, that might involve prying out one of your tiles.

Step 5

It is now time to kill mold. You do not need a special product to do this, just a simple bleach solution. Mix bleach and water at a ratio of 1:5. You can soak cotton balls with the bleach and let them set for a minute over the mold. If necessary, you can also try scrubbing at the mold with a small brush.

Step 6

It is now time to put everything back. Depending on what you had to do in step 4, that could mean replacing a tile or two and also sealing up your grout. After that, you can re-caulk (make sure you are applying the new caulk to a dry surface).

How Do You Prevent Mold in Shower Caulking?

It is great to know how to remove mold from the caulk in your shower–but it is far better not to have to do so at all. After all, every time you need to scrub away mold or remove and replace your caulk, it will take a lot of time and effort. How can you prevent mold from taking hold in your bathroom to begin with?

For one thing, make sure that going forward, you are using the right type of caulk. Silicone caulking is ideal for preventing mold. Look specifically for a product that contains a biocide.

For another, make sure that you are properly cleaning and maintaining your caulk on a regular basis. Doing this is necessary even if you have a “mold-proof” caulk containing biocide.


If you spot cracks in your caulk or grout, seal them before they can lead to more mold underneath your caulk. Wipe away surface mold before it can creep into vulnerabilities in your caulk.

Last but not least, make sure that your bathroom is as well-ventilated as possible. The less moisture you have trapped in your shower, the less inviting it will be for mold or mildew. Clean and dry your washroom doors, floors and windows and have proper ventilation.

Depending on your situation, this could entail anything from a minor change in your habits to a major renovation.

Frequently Asked Questions About Cleaning Mold in the Shower Area

Now that you know the basic method to stop mold in your shower, let's answer some frequently asked questions.

Q: How do you remove black mold from shower caulking?

A: The same methods that are recommended in general will work fine for black mold as well.

Q: How do you remove mold from silicone caulk?

A: The method we described above should work fine on this type of caulk.

Q: Does bleach really work to kill mold?

A: You may have heard that bleach is ineffectual for dealing with mold. Actually, it can be ineffective on porous surfaces. But in the bathroom, you are dealing with caulk, which is non-permeable, and the non-porous surfaces in your shower. So, using bleach and cotton balls should work just fine.

But if you do not want to use this method or if it is not getting the job done for whatever reason, there are some other ideas you can try.

Q: What are some alternatives to bleach to kill mold?

A: If you are not keen on using bleach, there are a number of other solutions you can consider for getting rid of mold.

One method that can work well is to combine water and hydrogen peroxide in equal parts. You can use a spray bottle to dispense it. You will need to wait for a little bit while the hydrogen peroxide goes to work, and then you can rinse it off.

Another option is to combine water and baking soda. You can try adding just a little baking soda to a spray bottle with water, then spray, wait, and wipe it down. Alternately, you can mix in more baking soda to form a thick paste, and scrub with a toothbrush.

Yet another idea is to use vinegar. You do not need to dilute the vinegar with water. You can just pour it right into a spray bottle. Spray the vinegar on the mold, and then wait. After the vinegar has had some time to work, you can rinse it off.

If you want to enhance your vinegar, you can add a bit of tea tree oil to your spray bottle. Spray it as usual, wait, and then rinse. With all of these methods, you can scrub if you need to.

Q: What if the mold growth is extensive?

A: Hopefully, you will find that you can clean the mold out of your shower yourself using vinegar, baking soda, or one of the other methods in this article.

But you might discover that your mold issue isn't confined to one small spot in your shower. If it covers a more extensive part of the shower, you may need to call in a professional to help you kill it for good.

Also, if you are currently unable to control the moisture levels in your bathroom, you might need to make modifications.

You may, for instance, benefit from adding ventilation to the room or upgrading it. If that is the case, that could also necessitate calling in a professional. It would depend on how extensive the work would need to be to achieve the result you are looking for.


Damp places are more prone of accumulating molds. If you washroom or shower drips, then the first step is to get the plumbing issues sorted. Killing mold growth in the tub and shower can take some time and effort, but if you can find the root of the problem, you can prevent more mold growth in your shower caulking in the future.

Kristina Perrin

Kristina Perrin

Kristina is an expert DIY home remodeler and mom to three. When she's not cooking or experimenting with new recipes, you can find her working on new home improvement projects or writing about her favorite kitchen appliances or DIY projects on Kitchen Infinity blog.

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