10 August Close up of a bathtub drain

How to Get Rid of Drain Worms

Posted by PlumbWize

Nothing ruins a relaxing bathtub soak or shower than the prospect of seeing drain worms or drain flies. They can also be found in sink drains or even the toilet. Most homeowners resort to pouring down drain cleaners in hopes of killing the drain worms once and for all. But this tactic is not only damaging to the pipes, but it may also not be effective in the long run. 

We put together this article to demystify the drain worm aka drain fly. We’ll talk all about this pest, what harm it can do, and most importantly, how to get rid of them once and for all. 

Without further ado, let’s get started! 

Life stages of a drain worm or drain fly


What are Drain Worms (or Drain Flies)? 

As given away by the title here, drain worms and drain flies are one and the same – only at different life stages. Drain flies belong to a family of insects called “Psychodidae” and are alternatively called moth flies due to their fuzzy moth-like appearance. Other names include sink flies, filter flies, and sewer gnats. They are gray and typically much smaller than the common housefly. 

Drain fly larvae (aka drain worms) are typically found in moist areas with organic matter – such as various types of home drains, stagnant moist mops, sewage treatment facilities, compost piles, and storm drains. These larvae are found in nature as well and serve an important function of decomposing organic matter. In a week’s time, they reach adulthood – aka becoming a drain fly. 

However, the benefits of having drain flies or moth flies stay in nature. Because in the home environment, they can be a serious nuisance and a potential health risk. 

Are Drain Worms Harmful to Humans?

Drain worms can look sinister but they are not known to bite or transmit blood-borne diseases to humans like other insects do. The health risk they carry lies in where they come from. They can spread bacteria where they go and if they’re coming up from the sink drain, they can potentially contaminate food. Moreover, drain flies have been reported to worsen the symptoms of bronchial asthma in some individuals. If left unchecked, drain flies can infest your home in large numbers.

How Do I Check If I Have Drainworms?

The most telltale sign of having drain worms somewhere in your home is the constant presence of adult drain flies. They are nocturnal but, during the day, you may spot them resting on walls. 

In some cases, drain worms can also crawl up from the drain. Putting a piece of sticky tape over part of the drain is one way to test whether or not you have drain worms in that particular drain. 

How On Earth Did I Get Drain Worms? (The Typical Reasons Why) 

If you have been away from home for a while, it can be possible to find drain worms in various places in the house where stagnant water and organic material are – such as drains, toilet bowls, and even puddles. 

The common way for you to have drain worms in these parts of your home is because a female drain fly or flies could have come in and laid clusters of eggs. They are, of course, naturally attracted to damp areas for their eggs. 

Close up of feet standing next to a shower drain

Can Drain Worms Be a Sign of an Underlying Plumbing Issue?

Drain worms are not always indicative of dirty drains. As we’ve covered in the previous section, stagnant drains will do well – dirty or not. There will most likely be moisture and organic matter in drains unless they are absolutely unused drains. 

But with that said, drains with more dirt and organic matter will tend to attract drain flies more. Additionally, semi-clogged/clogged drains are more suitable for these insects

Furthermore, damp areas in the house that are caused by pipe leaks can create suitable areas for the drain fly to live and breed. Another serious plumbing problem that the presence of drain flies can point towards is a crack in the sanitary sewer of your home. If your sudden drain fly infestation is accompanied by a sudden infestation of cockroaches, palmetto bugs, or even rodents, these are highly indicative of a problem with your sanitary sewer.

If you think that any of the above reasons is your underlying cause of drain worm infestation, then you need to address these plumbing problems straight away. Pipe leaks and cracks in the sanitary sewer will worsen over time and can cause a host of structural problems and health risks respectively. 

If your drain worm issue is stemming from a plumbing problem, there’s no doubt that the infestation will keep coming back. It would be best to call an expert plumber if you suspect that your drain worm problem is plumbing-related. 

How Do I Get Rid of Drain Worms?

Step 1: Rule Out or Remove The Clog 

The first thing to do is to check if the drain is not partially or fully clogged. You can do this by pouring ½ gallon of water down the drain and observing if it drains quickly. If it drains slowly, you might be dealing with a clog. Try using a plunger to see if it will get dislodged. If not, it’s best to call an expert plumber to clean the drain quickly and harmlessly.

Step 2: Kill the Drain Worms in the Infested Drains 

One of the ways to get rid of drain worms from an infested drain/s is to clean the drain with very hot water. We advise against boiling water as this can cause some materials to crack. Also avoid drain cleaners as these generally cause damage to the pipes. After the very hot water is poured, pour in white vinegar to finish off the remaining larvae.

Step 3: Remove Possible Breeding Areas 

There’s a possibility that drain worms are coming in from the outside. So try to remove any stagnant dirty water from around the house or in dirty gutters. If you have a composting pile, it can be a good idea to move it further away and cover it. 

But then, if the reason why you’ve had drain worms, in the first place, is a plumbing issue (e.g. a leaking pipe, cracked sanitary sewer), then definitely the drain worms will be back if these aren’t fixed first. So make sure to address all the plumbing issues that could be causing the infestation. You can do so by contacting an expert plumber. 

My Drain Worm Infestation Might Be Connected to Plumbing Problems – Who Can I Call?

Our expert plumbers here at PlumbWize can help you to quickly and easily troubleshoot and fix any plumbing problems that your home may have. We also respond to plumbing emergencies 24/7.  Whatever your plumbing needs may be, we’ve got you covered. We’re only a call away. Contact us today!


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