Discover 5 Ways Drain Flies Can Harmful or Dangerous to Humans

Written by Christina Eck
Updated: September 8, 2023
Share on:

Advertisement


When it comes to insects in the home, some are beneficial while others are not. One type of bug you might see is a Drain Fly, which may lead you to wonder, are drain flies harmful to humans? These unusual-looking flies live inside pipes and often quickly multiply.

With their distinctive look, a drain fly is not a pest you want in your home. Not only do they indicate the presence of unsanitary living conditions, but they can also cause some harm to humans. Below, we will walk you through the dangers of drain flies living in your home.

What Are Drainflies?

drainfly close up with black background

These

flies

are similar to gnats, except they are attracted to unhygienic conditions, particularly inside drains.

©Jojo dexter/Shutterstock.com

Drain flies (Psychodidae), or sewer flies, are small insects similar to gnats. They resemble moths, which is why they are also called moth flies in some areas. These flies are similar to gnats, except they are attracted to unhygienic conditions, particularly inside drains.

Despite being attracted to drains, these flies thrive in areas with organic material and water. These two conditions often are the reason drain flies will turn into an infestation, as they can easily breed with a food and water source. Their larvae will grow and thrive in organic matter, leading the bug to multiply quickly.

Drain flies can be identified by their unique fuzzy appearance. They have large wings and small bodies which span from ⅛ to ¼ inch in length. However, their most distinguishable feature is their pale brown or gray fuzzy body. But are drain flies harmful to humans?

Drain flies lurk in unsanitary places that may harbor harmful bacteria like mold.

5 Ways Drain Flies Are Dangerous to Humans

While drain flies seem harmless, they can become a major issue if left alone. The fly’s presence indicates the environment isn’t sanitary and can contribute to individual allergies, spreading germs, and much more. Below, we’ll give you a rundown on are drain flies harmful.

Reason #1: Drain Flies Cause Allergies & Respiratory Issues

When houseflies die, their decaying bodies will spread particles into the air.

©Birgit Bierschenk/Shutterstock.com

Drain flies are a bit different from your standard housefly or gnat. Instead of releasing particles, they don’t become harmful until they die. When they die, their decaying bodies will spread particles into the air.

Once a person inhales these particles, it can end up triggering an individual’s allergies or even mess with any respiratory issues a person may have. Those suffering from asthma can become triggered and have more frequent attacks. Additionally, individuals with allergies will start to have worsening symptoms.

Reason #2: They Spread Bacteria

Unlike mosquitoes, durian flies can’t spread diseases or illnesses. They do not suck blood or eat humans, so they don’t carry any illnesses. Instead, they can spread bacteria.

Drain flies lurk in unsanitary places that may harbor harmful bacteria like mold. These unsanitary living conditions mean they will carry the bacteria from their living area and spread them around the house. If a person comes in contact with any surfaces the fly touches, they can become exposed to the bacteria.

Reason #3: They Live in Unsanitary Conditions

So, how else are drain flies harmful? When there is a presence of drain flies, it indicates unsanitary conditions. Drain flies are typically attracted to wet, moldy, dirty places. Clogged, backed up, or malfunctioning drains will attract these flies.

That means there is leftover organic matter and a water source for them to feed. If those conditions continue, the bugs will multiply, making the area their nest. It’s best to locate the source and clean the drains before they have a chance to expand to avoid an infestation.

Reason #4: Drain Flies Contaminate Food 

Drain flies are attracted to more than just waste. If they are in your home, they are likely eating and laying their eggs on other surfaces, including food. Any surface containing food particles will attract the drain flies, including countertops or trash bins.

Once they know where a food source is, they will lay their eggs, contaminating food. Common places in the home they infest include the fridge, pantry, and pet foods. They will lay their eggs in the smallest openings if you don’t have everything properly sealed. After a few hours, drain fly larvae will hatch and further contaminate any food. 

Reason #5: Drain Flies Are Mentally Irritating

Aside from the fact that drain flies are unsightly, they also make a horrible buzzing noise. Their small wings can become irritable as they fly past you. If they have a chance to lay eggs and expand their nest, more flies will buzz around. For those with anxiety, sensory sensitivity, or OCD, the bugs will only make these conditions worsen.

Drain Flies FAQs

Moth Flies in a drain pipe

Drain flies are attracted to more than just waste. If they are in your home, they are likely eating and laying their eggs on other surfaces, including food.

©Jay Ondreicka/Shutterstock.com

Do Drain Flies Bite?

No, this common household insect doesn’t bite or sting. In fact, it rarely comes into contact with humans. Drain flies can spread bacteria but do not try and drink blood or eat human skin like other insects. 

Can Drain Flies Lay Eggs in Humans?

Drain flies do not lay eggs inside of humans. The only type of insects that lay eggs inside humans fall under the parasitic family. A drain fly is not a parasite and won’t lay eggs inside of humans, only in decaying organic matter.

What Are the Signs of a Drain Fly Infestation?

Since drain flies multiply within as little as 48 hours and lay 1,000 eggs, it’s almost impossible not to have an infestation on your hand. A drain fly infestation will start in the pipes and drains of your home or business. You can take a piece of tape over the drain to detect an infestation.

The small flies will get stuck as they attempt to exit the drain. Depending on how much you catch, you can tell how big the infestation is. 

How Do You Get Rid of Drain Flies?

If you notice a drain fly, you must clean its breeding grounds. This includes pouring hot water down drains, using drain cleaners, and scrubbing where possible. Drain flies are notorious for staying alive and not getting washed away. Despite cleaning, you must call a professional if the infestation is still there.

Summary of 5 Ways Drain Flies Can Harmful or Dangerous to Humans

RankHarmful Way
1Drain Flies Cause Allergies & Respiratory Issues
2They Spread Bacteria
3They Live in Unsanitary Conditions
4Drain Flies Contaminate Food
5Drain Flies Are Mentally Irritating
Table of 5 Ways Drain Flies Can Harmful or Dangerous to Humans

The photo featured at the top of this post is © Birgit Bierschenk/Shutterstock.com


Share on:
About the Author

Christina Eck is a writer at A-Z Animals, primarily focusing on animals and travel. Christina has been writing about and researching animals for more than seven years. She holds a Bachelor's Degree from the University of Alaska, Anchorage, which she earned in 2019. As a resident of Washington State, Christina enjoys hiking, playing with her dog, and writing fiction and non-fiction pieces.

Thank you for reading! Have some feedback for us? Contact the AZ Animals editorial team.