Get Rid of Drain Flies – Prevention & Remedies


Though they can be very annoying, learning how to get rid of drain flies is not terribly difficult. You just need to understand their life cycle and habitat and implement some simple interventions.

What are drain flies?

Drain flies, or sewer flies, are flies that can usually be found in bathrooms and kitchens, near drains. It will be explained below where these creatures actually come from.

While the insects are normally nocturnal, they can orient themselves around light and this can make them look like they are attracted to lights. The life duration of an adult insect can be of about twenty days.

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Where do sewer flies come from and what do they eat?

Sewer flies come from aquatic habitats that experience intermittent submersion, where they dwell in the form of larvae. Examples of such environments can be polluted and shallow waters or organic solids with high moisture levels.

Here they eat decaying organic material from mud, moss and water. As adults, these insects come in human buildings and they can often be seen around the drains of your bathroom and kitchen. Larvae can live here too, case in which they feed on bacteria.

Adults can feed on flower nectar. The gelatinous organic slime that has accumulated in sinks is a perfect medium for the development of larvae.

How do drain flies look

Drain flies have wings that are covered by moth-like scales and they are also called moth flies due to this reason. Their size is of less than two millimeters and the adults have long antennae.

The wings have the shape of leaves and the color of these insects is usually a dark color. The hair on these wings is extremely fine and water-repellent, making these flies immune to drowning.

Do drain flies bite humans?

Drain flies do not bite humans and they are actually not harmful for humans. But, when they are in large numbers, they can become a nuisance.

The small size of the adults can help them to easily pass through regular windows screening. Because of the large populations that sometimes may be present in a home, eliminating these insects can be really tough.

The life cycle of drain flies

An entire life cycle can end in one to three weeks. Adults rest during the day near plumbing fixtures, the side of showers and tubs, or in shades. In the evening, adults start their activity by flying above drains and sinks.

In sewage filter plants, these insects can breed in large numbers and they can reach homes with the help of the wind. Wind can carry them up to even a mile.

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Drain flies pest control

The most efficient way of controlling sewer flies populations is to remove gelatinous slime (also known as black gunk) from the drains. This material builds up from time to time and allows larvae to thrive. If you want to clean the drains, you need to do it with a special drain cleaner that can be bought from the stores, but you can also do it with a brush.

Using beach or insecticides is not necessary, especially because these substances are not even efficient. The hair from the wings of these insects will prevent these substances from working well. The flies will leave when there is no gelatinous slime. Black gunk can also build up around leaky pipes, or around sewage ponds outdoors.

If you still have sewer flies indoors after you have cleaned all your drains, the cause may be a leaking pipe under the house. Drain cleaners do not work on clogged drains. Clogged drains should be cleaned with a chemical drain cleaner. In order to avoid the buildup of black gunk, you should use cleaners for drains several times every year.

How to remove adult sewer flies

A standard fly swatter can be used for catching as many flies as you can when they hover around the drain. An additional method is the use of a spray for insects. Make sure that all doors are closed before using the spray. Leave the spray to work for like fifteen minutes and return. Open all doors and windows to avoid intoxication.

Steps for getting rid of drain flies

The first step necessary for getting rid of drain flies is to inspect your home’s drains, indoors and outdoors. These flies don’t rapidly spread to other places in a home once they have established their place where they thrive.

This can be turned to your advantage, because you can quickly eradicate them from that place and you will prevent future spreading to other locations. Another thing to do regularly is to dry all the drains before you go to sleep.

You need to be sure you have drain flies and not other types of flies in your home before you take any measure to eliminate them. In order to catch some flies for studying their nature, you can use a piece of clear tape on each drain.

Don’t cover the drains completely, as you will prevent the insects from flying up and you will not trap them. Leave the tape for a day or more and then check it. Repeat the process if there are no flies trapped from the first attempt.

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Another step to take is to remove the hair that is trapped in the drain, or take out the filter if you have one for cleaning it of hair.

Hair, grime and debris can be a good breeding ground for these insects. The drain can be moistened with warm water. But, this is only required if the drain has been used rarely. Drains that are used a lot are already moist enough.

The next step is inserting a metal pipe brush and extending it as long as is needed. This is useful for eliminating the grime from the side of the pipe.

A plumbing snake can be used to take out the grime. Pouring special gel for cleaning drains is the next step. You could use traditional solutions instead of gel, such as baking soda, vinegar, bleach and boiled water.

However, experts say that gel is the best. Flush the drain with water and use a plunger to take out any remaining materials. Call a professional if you can’t follow the steps.

Articles Related to Drain Flies:

  1. Moth/Drain Flies – Clemson University
  2. Getting Rid of Gnats
  3. Nuisance Nonbiting Flies – University of Florida
Categorized as Flies

By David Jackson

I enjoy learning about new pest control strategies and sharing what I learn at I aim to create a reliable resource for people dealing with all sorts of pest issues.

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