Nobody likes seeing black marks in their bathtub. They're not just unpleasant to look at - they can make you wonder if your bathroom is truly clean.

But don’t worry - I’m here to help!

In this post, I’ll shed some light on the cause behind these stains and show you how to remove black marks on bathtubs.

What Causes Black Stains In Bathtub?

Those black marks could be caused by a bunch of different things. Here are the most common ones:

#1 Mold And Mildew

Let's start with the most common reason you'll see black marks on bathtubs: mold and mildew. 

These little fungi really love bathrooms. You'll often spot them as black dots or lines, especially where the caulking is or around the grout. 

Bathrooms are basically perfect for mold and mildew to grow because of all the moisture and humidity.

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If you don't have good ventilation and don't clean regularly, they'll multiply pretty quickly. 

This isn't just about looks - it can affect your health too.

#2 Hard Water Stains

The next reason behind black marks on bathtubs is hard water stains.

The minerals in your water, especially iron, can turn dark over time and leave stains on your tub. 

These aren't the kind of stains that show up overnight - they develop gradually, and if you don't deal with them right away, they can be really tough to remove. 

This happens a lot in places where the water has lots of minerals in it. 

When water dries on your tub, it leaves these minerals behind, and they can form a scale that gets darker as time goes on.

The longer you wait to clean them, the harder they are to get rid of.

#3 Stains From Products

Those bath products you love using? Some of them can leave dark marks on your tub. 

This includes things like oils, dyes, and even your cosmetics. You might not notice these stains right away, but they can get more noticeable the more you use these products. 

Bath bombs, colored soaps, hair dyes, and even natural products can create these stains. 

When these products mix with mineral deposits or soap scum, they can create marks that are extra stubborn to clean.

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#4 Rubber Decomposition

Here's one that most people don't think about - the rubber parts in your faucets or hoses can break down over time. 

When this happens, they leave little black specks that spread around when you try to wipe them off. 

This tends to happen more with older fixtures or rubber parts that aren't great quality. Hot water and certain cleaners can make this breakdown happen faster. 

The best way to prevent this is to check your rubber parts regularly and replace them when needed.

How To Remove Black Marks On Bathtub

Now that you know what causes these black stains on your bathtub, let's take a look at how to get rid of it.

Bleach And Baking Soda

The easiest way to remove black marks on bathtubs is with bleach and baking soda.

Create a paste by mixing equal parts bleach and baking soda. Apply this mixture generously to the stained areas and let it sit for approximately 20 minutes.

This works really well because the bleach tackles the stains and kills germs, while the baking soda helps scrub them away without scratching your tub. 

After waiting, take a soft sponge or an old toothbrush and gently scrub the area, then rinse it thoroughly.

This works especially well on mold and mildew, but make sure you open a window or turn on the fan while you're doing it.

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Vinegar And Dish Soap

Want a more natural way to clean? Mix the same amount of white vinegar and dish soap in a spray bottle. Spray it on the marks and let it sit for 5-10 minutes. 

The vinegar works on breaking down minerals and killing mold, and the dish soap helps remove any oily residue.

This is great for regular cleaning and helps stop new stains from forming. 

Just wipe everything down with a gentle sponge and rinse well.

Hydrogen Peroxide Paste

Another great way to get rid of black marks on bathtubs is with hydrogen peroxide.

Take some hydrogen peroxide and mix it with baking soda to make a paste. Put it on the black marks and give it about 20 minutes to work. The hydrogen peroxide releases oxygen that breaks down the stains while cleaning the surface. 

The baking soda helps with scrubbing and gets rid of any bad smells. It's safer than using bleach and doesn't have strong fumes. 

Use a sponge to scrub gently, then rinse everything off.

This is really good for dealing with mold and mildew stains.

Magic Eraser

For those really stubborn marks or if your tub has a textured surface, a Magic Eraser is highly effective. Just get it wet and gently scrub the stains. 

The tiny abrasives in the Magic Eraser help lift the stains without needing harsh chemicals.

This works really well on rubber marks and surface stains, but don't use it too much on delicate surfaces.

But be careful - test it on a small hidden spot first because it can damage some surfaces if you're not careful.

Final Thoughts

The best way to handle black marks is to stop them from showing up in the first place. 

Make sure your bathroom has good airflow, wipe down your tub after you use it, and take care of stains as soon as you see them. 

If you keep getting stains, you might want to check if any rubber parts need to be replaced.

FAQs

Bathtub Stains Won't Come Out

If bathtub stains won't come out with regular cleaners, try filling your tub with hot water, add plenty of OxiClean, and let it sit overnight before scrubbing.

How To Clean Plastic Bathtub Stains

To clean plastic bathtub stains, sprinkle baking soda directly onto the stains and spray white vinegar over it. Let the mixture fizz for a few minutes, then scrub with a soft brush or sponge. Rinse thoroughly with warm water.