If You See Black Slime on a Faucet, This Is What It Is

That black slime is gross, but it's ultimately harmless.

I’ll be honest—I’m not a big fan of cleaning the house. In fact, I’m always on the lookout for cleaning hacks so I can get through the task as quickly as possible. However, when I’m in the mood to clean, I want to scrub everything, down to the bathroom faucets.

As it turns out, some people have to scrub their faucets a lot more than others, and that’s because of black slime. If you’ve found this slime on your faucets and simply can’t seem to get rid of it, there’s a simple explanation—and it has nothing to do with your sink or bathtub being dirty.

Why You Might Find Black Slime

If you find black slime around the holes of your shower faucet, it’s due to oxidized manganese and harmless bacteria feeding off the minerals in the water. This might also show up in the form of black stains in your toilet bowl. Most water in the United States contains dissolved manganese, along with other minerals. The slime comes from bacteria feeding off the minerals!

Neither the bacteria nor manganese are usually harmful in drinking water. The World Health Organization recommends a concentration of 0.05mg/l in drinking water, and if you choose to filter your water, that level can easily be lower.

How Do I Get Rid of It?

If you’re worried about manganese or bacteria in your drinking water, the most permanent solution is to install an under-the-sink RO (reverse oxidation) water filtration system in your kitchen. You can also install an RO filtration system in other problem areas, or even for the whole house.

You can regularly clean your faucets, of course, and see if flushing the main supply line gets rid of the black slime. These are most likely to be temporary fixes, especially if the mineral is present in the main water supply, but since manganese is overall harmless, this shouldn’t be an issue.

While you’re at it, don’t forget to check out these other bathroom cleaning tips!

Amrita Thakkar
Amrita is an Assistant Digital Editor at Taste of Home. As a writer and amateur photographer, she often ends up applying these skills to her one great love: food. She can usually be found researching global cuisines, at the farmers market, doing yoga, or looking up new places to travel to.