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How to Get Rid of Black Worms in the Bathroom

Nothing is more disturbing than seeing small black worms wiggling in your shower drain.

How did they get there, and where did they come from? Does their presence mean your bathroom is contaminated with them? Are black worms dangerous to your health? How do you get rid of them?

Learn all about black worms in your bathroom, how to get rid of them, and how to keep them from returning.

black bathroom worm

What Should You Know About Black Worms?

Black worms are the offspring of drain flies. They often appear in drains or fall from taps that have formed a slimy residue inside.

You will find blackworms in water-rich environments like your bathtub, shower, washbasin, and toilet bowl.

Nighttime is when drain flies and their larvae are most active, so this is when you will notice them crawling up from your bathroom drains or p-traps.

Drain flies are also prolific breeders, and with only a three-week lifespan, they breed almost constantly. Their eggs hatch within 48 hours, filling your bathroom drains with new batches of black worms.

Black worms are tiny in size at less than three inches in length. These worms swim with a corkscrew motion, have a slim body, and are fairly easy to identify. You may think there are tiny black jumping bugs in your bathroom as mature black worms become drain flies that hop about.

These worms don’t bite, and they have no interest in humans other than to feed on decaying bio-matter like the hair and skin cells clogging up your drains.

You will notice more of these wiggly critters after a period of rain as they come up to breathe when your pipes and drains have been filled with water.

Some subspecies of black worms even breathe through their tail, and you will see them stick one end of their body up out of the drain water. They also breathe through their skin, making it difficult to drown them.

With their incredible regeneration powers, it is also not useful to squash them.

While black worms in your bathroom don’t pose a risk of carrying diseases, they do indicate a worse problem happening in your drains and pipes.

Black worms wiggling in your bathtub means you have an infestation of drain flies and a buildup of sludge in your drain pipes.

Why Are There Black Worms in My Bathroom?

The inside of most bathroom drains and pipes or taps is usually quite slimy and sludgy, which forms a perfect place for black worms to attach themselves to.

Black worms are attracted to biomatter or decaying plant matter, which is why they love being in your drains, pipes, and toilets.

Black worms especially love drains that don’t work so well, and blocked drains will quickly hatch a whole colony in stagnant water.

While you may believe you can’t possibly have black bathroom worms in your home, since you’ve never seen drain flies in your home, they travel along your drain system.

Therefore, the actual breeding zone may be outside your home, and you only see the black worms in your bathroom as a result of these worms seeking food and oxygen.

All the biomass in your toilet enables black worms to feed and encourages them to crawl up the drain system.

They will happily snack on whatever goes down your toilet drain, so be sure to clean this up regularly. Signs of a poorly maintained toilet drain include having black worms in the toilet bowl or toilet tank.

Black worms move along your shower tile grouting as they look for mold and other biologicals they can eat.

Black worms will follow any dampness. You may even find black worms in your bathroom carpet or floor rug.

How Do Black Worms Get Into the Bathroom?

Drain flies crawl up pipes or down drains, where they lay hundreds of eggs. These eggs hatch, producing the larvae or black worms.

Following the airflow coming down your drain, these worms wiggle their way up the drains and pipes into your bathroom, where they emerge from the shower or bathtub drain at night to feed on the organic materials left behind from your body.

You will often find black worms swimming in the toilet bowl as they crawl up the toilet drain. Even the peroxide or ammonia you pour into your toilet bowl doesn’t keep them from thriving.

Since these worms crawl up drains and along grout lines of your shower where fungus and mold thrive, they are not deterred by flushing water down drains.

Your bathroom taps are another entry point, and sticking your finger into your taps will reveal whether there is a buildup of sludge inside your taps, which is exactly what black worms need to thrive.

In your bathtub, you will find black worms around the drain or in the bathtub taps too.

Wet or moldy bathroom rugs will attract drain flies, and these will lay their eggs in the rug fibers. The eggs will hatch, producing black worms, which will infest your bathroom rugs.

How to Get Rid of Black Worms In Your Bathroom

When you have a black worm problem, you need to prepare for a long-term cleaning solution. The main source of these worms may not be in your bathroom. Since drain flies breed so much, you will have new generations of black worms hatching almost daily.

Follow these steps to remove black worms from your bathroom:

Flush Your Drains

The first step we recommend for getting rid of black worms is to flush all drains with hot water. Next, open all outside drains and flush these with boiling water too.

If you notice the water draining away slowly, it means you have a blocked drain, and you may require the services of a plumber to help you clear the drain.

You can also rinse the outside of your pipes and drains with hot water to release the sludge inside them. Black worms love to feed off this sludge, so they will die off if you eliminate their food source.

Add Some Fizz

If you have a serious buildup of sludge and gunk on the inside of your drain pipes and around your toilet tank and bowl, then you need some fizzy power. Adding baking soda before rinsing with hot water can definitely help you clean off the slimy lining the black worms hatch from.

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You can also opt for white vinegar or ammonia, but be careful not to use both together as this produces a toxic gas. Instead, pour a cup of vinegar down the drain, wait a few minutes, then run the warm water tap for several minutes.


If you don’t have baking soda or vinegar handy, you can also use a bottle of Coke to clean off the sludge that attracts black worms.

While it may seem like a waste, the phosphoric acid of the Coke will dissolve any sludge that is clinging to your drains or pipes.

Pour the soda down the drain, then wait several minutes while the fizz works on the sludge. Rinse by running your warm water taps for several minutes.

Repeat this procedure for several consecutive days until you’ve eliminated any sludge still clinging to the insides of your drains or pipes.

What About Your Toilet?

If you have black worms in the toilet, it can be harder to clean since it is a naturally wet environment.

Close the shut-off valve of your toilet. It’s normally located on the water supply pipe that runs to the tank. Flush your toilet, letting the tank run empty. It may be necessary to flush twice.

Then repeat the procedures as above, using either warm water, baking soda, vinegar or ammonia, or a bottle of Coke. Let these natural cleaners get to work inside the bowl and tank, then rinse with a few buckets of hot water added to the tank, which you can use to flush the toilet.

Great! Now open your stop valve, letting your tank fill as normal.

… And the Shower?

Showers can be tricky as their drains tend to collect hair. If you have long hair, this can create a nice and icky cocoon in the drain pipe that black worms love to hatch in.

This can also be quite a resistant space to cleaning. However, by lifting the drain cover and using pliers and tongs or a drain snake, you can get rid of the hair plug out of the drain and dispose of this with your household garbage.

Once the plug is removed, you can remove the remaining sludge as per the above steps.

How to Prevent Black Worms From Coming Back to My Bathroom 

Preventing a reinfestation of black worms in your bathroom will be a lot simpler once you have cleared the sludge and mineral buildup that attracted them.

You can use a regular microbial-based drain cleaner once a week to clean out any new sludge that may form in your drains.

If you want to go the natural route, then pouring a cup of vinegar down your bathroom drains every week will also help clean out any limescale that could cause biological material or sludge to cling to pipes.

Sludge attracts black worms or drain flies. Follow this by running hot water through the drain for several minutes.

Ensure your drains are all flushing correctly, as stagnant water will form sludge quickly and attract drain flies that will breed and create black worms.

The Ultimate Guide to Bugs in the Bathroom

Interested in learning more about the variety of bugs that can infest your bathroom? Our expert guide offers an in-depth overview of the presence of little bugs in the bathroom, along with actionable advice on how to effectively deal with them.

Dustin Carter

Dustin is the founder of Alpine Pest Control Solutions, the #1 best-reviewed pest control company in Austin, TX. He has been dealing with household pests for more than 15 years.

Dustin enjoys the opportunity to share with homeowners safe pest control practices that they can apply and unique tricks he has learned throughout his career as a pest control expert.

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