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Drain Flies – Why you have them, and how to get rid of them.

Drain flies are known by many names, some of which include; moth flies, sink flies, or sewer gnats. They are small winged bugs that look similar to moths in that their bodies and wings are furry. Drain flies are problems for homeowners when their population grows excessively in your home’s plumbing and water system. As the name would suggest, they are commonly found in drains as they are attracted to moist, organic areas – this is where they get their nutrients. They are also attracted to decomposing or decaying organic material and compost piles. There are over 4700 species of drain flies, they are most harmless however they are seemingly indestructible and an unwavering annoyance when found in your own home.


The adult drain fly is hard to kill and a particular pest-y pest because of the scales on their wings. They are designed to thrive in wet, dewy areas. When water, regardless of temperate from freezing to boiling, hits their wings the scales come off, leaving a residue. They are virtually unfazed by water being poured down the drain in hopes to kill the colony. Bleach also has a similar effect when trying to kill drain flies, the effort is mostly frivolous as well as a waste of bleach!

A drain fly infestation is usually only noticed when a couple of the adults have flown through the pipes and into the home. The flying pattern of drain flies is irrational and jerky, they mainly stay in the area wherein which they are most comfortable; a cold, gelatinous bed they’ve created to hatch their larvae. If the flies are present in your home that means there is probably a clogged drain somewhere and that is why you can now see them flying about. It is necessary to find the clogged drain and clean it. The best way to avoid having an infestation is through regular cleaning of your home’s drains and pipes. The drain flies are partial to wet areas with decaying organic waste. If you have a garbage disposal or regularly through food down your sinks it is even more likely that you will be infested with drain flies.


Drain fly larvae pupate and turn into adults with six legs and a set of furry wings. They usually live about two to three weeks, though sometimes an entire generation of drain flies can be born and die within a week. New larvae are rapidly produced, and though their lifespan is short fully formed adult drain flies are rapidly replacing those that have moved on to their next life.


If you suspect that you have drain flies in your home a good way to find out for sure is to cover your shower drains and sink drains with tape. Drain flies are often found in the bathroom because showers are the most likely to have a leaky drain in your home. When the drain flies attempt to fly out of your plumbing they will get stuck on the tape and then you will know for sure. It could take a couple of days, if you will be using the sink make sure to cut little holes into the tape so the water can still drain. Once you have found the flies on the tape it is time to take action. First, you must remove all organic debris and clean your drains. If you have found the flies in your shower you must drill a hole near the plumbing either below or in the wall. Drain flies will be living in there, hundreds more than you found on the tape. They are also extremely attracted to light so they will fly out from the hole.

You can kill adult drain flies by:

  1. Using a chemical spray: There are sprays made specifically for the killing of drain flies. However, these sprays are toxic so if the infested area is the kitchen it is better to use another method.
  2. Remove all leaks: After you’ve cleaned the drain and removed the organic material all drainage leaks must be sealed or the problem will persist.
  3. Use a catcher: To destroy the breeding ground you can use a wire catcher to feed through the drain and break up the larvae from their gelatin home. Afterward place the tape back on the drain, poking air holes. Leave the tape on for at least a few days to a week.

What do you think?

Written by Anta

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