What Is the Black Stuff on My Shower Head?

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You are seeing black stuff on your shower head again and this time you are convinced that mold and mildew are not the culprits. It is something else and not just a matter of humidity and moisture. That brings the question, what is the black stuff on my shower head?

What Is the Black Stuff on My Shower Head?

The black stuff on your shower head is most likely oxidized manganese and bacteria. The interaction between the oxidized manganese and the bacteria that eat it produces black gunk and stains. Don’t worry, the presence of bacteria and manganese in the water is not a threat to one’s health in most cases.

Iron is another metal in water that leaves stains in your plumbing fixtures. This time though, the stain could be red, orange, or brown, depending on the oxidation level. In general, the presence of iron-eating bacteria in the water is also not harmful to your health.

Black stuff on the shower head ready to be cleaned

Manganese and Bacteria Effects on Your Health

Manganese is present in water and not only in the foods we eat. This is an essential mineral that has a specific function in the body. However, having manganese at a level exceeding 0.05 parts in a million in your drinking water can be fatal.

Knowing that a specific type of bacteria uses oxidized manganese to fuel themselves up and multiply, the question becomes: is the water still safe with their presence?

Yes, the water is still safe despite the small presence of oxidized manganese and bacteria. There is no evidence showing the harmful effects of such contamination.

Bacteria that Eat Oxidized Metals for Calories

Most advice online would tell you that the most common causes for black stuff in faucets and showerheads are mold and mildew. This is perhaps because not many people until now know the existence of manganese-related bacteria. 

Scientists have been suspecting the presence of manganese bacteria for more than a hundred years already. However, they were able to discover them just recently. In fact, studies about it are still being published until a few months ago.

Iron in Water

Iron is another naturally-occurring mineral that is present in water. Oxidized iron and the bacteria that thrive in it, on the other hand, causes red stains in water and plumbing fixtures.

Like manganese, iron in small amounts does not make the water dangerous to health. There is also no evidence of any harmful health effects of iron bacteria.

How Does Manganese and Iron Develop Black Stains and Buildup?

Iron and manganese are one of the most common elements found on earth. In their most preserved form, they are transparent, colorless, and water-soluble. However, they change in color when exposed to oxygen. Then, they become less soluble.

Shower head set

Going further, these bacteria feed on oxidized manganese and iron. As they borrow electrons from them, the reaction creates the black or red residue.

As the process continues and with the bacteria thriving uninterruptedly, a buildup of gunk develops. When left unmanaged, this would cause clogging in plumbing fixtures and reduced water pressure.

How Can You Test for Manganese and Iron in Water?

When you have high levels of manganese and iron in your water like the water quality they have in places like Nebraska, your chances for having black gunk and red stains are higher. Ignore this and you are likely to deal with the same problem over and over. 

Also, it is not just the black stuff that you should be worried about. As we’ve mentioned earlier, high levels of manganese in the water is fatal.

Unlike manganese though, you can easily detect iron on your own by the smell of and/or the presence of tiny, yellow, or orange particles in the water. You can run a test for iron in the water, too, to get the exact concentration you have in your water.

How Much Does It Cost to Test Water for Manganese and Iron?

Water testing prices vary by state and the prices tend to go higher with more compounds and contaminants to test for. However, you can save a considerable amount when you have your water tested in a public laboratory.

In South Dakota, for example, the public laboratory only charges $14 for a manganese test. Alternatively, you can buy a simple test kit that costs $10 to $30. Bigger test kits cost more. 

Ways to Treat Manganese and Iron in Water

There is hardly any procedure to treat manganese and iron in the water that gives permanent results except reverse osmosis. Although a guaranteed process, there are some considerations when you choose this procedure. First, you should know that this is an expensive option.

Modern shower room

On the other side, here are some ways to treat manganese and iron in the water. All processes for treating water with manganese and iron are a bit complicated so we recommend you call a professional is recommended.

  • Ion Exchange: This uses an ion exchange process to remove the precipitated form of manganese and iron in the water. 
  • Water Softener: The water softener procedure only removes manganese and iron that are in their unprecipitated form. Minerals in their unprecipitated form are more difficult to remove because they are barely detectable. This is a job for a filtration system.
  • Oxidation Filtration: In this process, water stored in a tank undergoes treatment. It would use either chlorine or potassium chloride to oxidize manganese and iron. Later, it will be filtered to collect the oxidized minerals. Draining the tank after every treatment is necessary to get rid of the remaining manganese and iron. 
  • Reverse Osmosis Filtration: this process also removes other impurities and not just manganese and iron. Although water can easily pass, reverse osmosis uses a permeable membrane to strain larger molecules and then keep them aside until it’s time for draining. Reverse Osmosis is an effective approach that can also remove odor through its carbon filter. However, it will only work with high water pressure.  Also, this may not be an effective means to filter water in huge volumes.

Related Questions

Before we finish this article, we want to address related and common questions around this subject. 

What is the Black Mold in a Shower?

The black mold in the shower is, in most cases, not really mold, just manganese. The black color indicates the presence of oxidized manganese and the bacteria that eat away at it. Bacteria that thrive in oxidized iron also produce a greyish color sometimes, but usually red, brown, or orange.

What Causes Black Stain on Shower Tile?

The black stain on shower tiles is also caused by manganese- and iron-related bacteria. They borrow electrons from these oxidized minerals and produce a black color as the reaction from the process.


The black stuff on your shower head is the end reaction of oxidized manganese and iron in the water that is being eaten by bacteria. Both the oxidized manganese and the metal bacteria are not fatal in small amounts and you have options to treat your water if their presence bothers you.

Allen Michael is the Founder and Editor of Home Viable, a website that he started to provide readers with tips on home efficiency and automation. He draws on his engineering background combined with his family-of-four experiences for his articles.