Hygiene problems are getting worse in commercial restaurants, home kitchens, and outdoor cooking places. Among many other tiny flying insects, the commonly found is a drain fly. There are many names of drain flies including filter flies, sink flies or sewer gnats. 

These insects are true flies and have short, hairy body along with wings which makes them a moth look alike, and for this reason, they are also known as moth flies.


Drain flies are commonly found in areas where hygiene is not properly maintained like bathrooms, but they are not known to carry any human disease. Nevertheless, these flies play their part as an opportunistic agent of myiasis and can be problematic.
Signs of a drain fly infestation
Similar to most other flies, the most significant sign of drain fly infestation are the adults. Typically, they are seen resting on the walls in the bathrooms or anywhere near the breeding areas where they have ideal conditions to grow and multiply. In addition to that, you can also observe larvae wriggling in the breeding materials. 

Do drain flies bite?
No, drain flies do not bite humans. They only feed on organic matter or at times they visit flowers. The pupae and larvae of these flies live in the thin gelatinous film that is found in the drains, filter stones or septic tank field lines. They feed on decaying vegetables, microscopic animals and plants, and sediment. The drain flies that belong to subfamily Phlebotominae do feed on blood too, but they are rare and not commonly found in the households. 

Why should I be concerned?
As mentioned above drain flies do not bite humans and are harmless in most cases. However, their habitat is quite unsanitary, and according to some studies, there is and evidence that drain flies can carry pathogenic bacteria. They are also capable of multiplying quickly and can create a nuisance for you. They can cause mechanical contamination of food because they originate from a filthy source.

Tips for prevention and control
First of all, you need to find the breeding source if you want to get rid of drain flies completely. Most of the time, they are located in the kitchens or bathrooms resting on the ceilings or walls. They are not good at flying so, wherever you see them, their breeding source is near.


  • Their larvae breed in the slime that is found in the drains, so eliminating that thin film of slime would be a good starting point.
  • Clean your drain from the outside and then pour 4 to 5 liters of warm water to moisten it. 
  • Then take a metal pipe brush and push it through your drain pipe. Keep the movement up and down for cleaning the sides of the pipe. Moreover, you can also use the plumbing snake to clear out the grime. 
  • The final step is to pour some drain cleaning gel into the pipe and try to coat its sides and let it be for a few hours. This gel is specially designed to get rid of the organic matter from the drains and pipes.
  • After a few hours cleaning your pipes with plenty of water. You can use a plunger to clear off any remaining organic matter.
  • You can kill the adults with chemical sprays or fly swatters. 

Drain flies are not harmful to humans because they do not bite and don’t carry diseases either. However, due to the unsanitary nature of their breeding source and their ability to quickly multiply they can cause plenty of nuisances. Therefore, you need to control your drain fly infestation with the help of following simple steps mentioned above. Make sure to keep your drains clean and free of clogging so that you can prevent their return in your bathroom and kitchen.