How To Identify Drain Flies?

Hey there! Some links on this page are affiliate links which means that, if you choose to make a purchase, I may earn a small commission at no extra cost to you. I greatly appreciate your support!

Drain flies are common pests found in both homes and gardens. They are found near drains and other moist environments such as garbage disposals and recycling bins. They tend to originate in filthy conditions, and the possibility of physical transmission of microbes is real. 

Drain flies, or Fannia canicularis, are the most common fly found in homes, buildings, garbage containers, septic tanks, etc. Continue reading to find out more about drain flies. 

How to Identify Drain Flies? (drain fly size)

fly, bio, logo

Drain flies, also known as moth flies or sink flies, are a type of fly that is about the same size as gnats and fruit flies. They are small, moth-like creatures that cannot fly very far.

They get their name because they are often found near drains, sewers, and moist environments.

Drain flies are a common household pest identified by their small size, about 1/8th of an inch long with brown facial hair, and short lifespan. They typically live for 8 to 24 days, during which time they will mate and lay eggs.

Drain flies can be a nuisance, laying and hatching up to 300 eggs in 48 hours. If you’re having a problem with them, it’s important to address it before they have a chance to spread throughout your pipes.

By identifying the drain fly size and knowing what to look for, you can get ahead of the problem before it becomes too big.

Drain fly life cycle

invade, icon, michigan

Drain flies go through a complete life cycle that lasts about two weeks. Drain flies typically have a short life cycle and are most active at night. They can often be seen hovering around drains and sinks. So, here is the life cycle:

Drain fly eggs.

Drain fly eggs are often deposited in sewers and drains. Depending on the species and environmental conditions, the eggs will hatch within 32 to 72 hours. Once hatched, the drain flies will go through a four-stage life cycle before becoming adults. 

Drain fly larvae

Drain fly larvae and pupae can be found in thin film, often present in drains, septic tank field lines, and similar environments. The larvae feed on fungi, bacteria, algae, and other small organisms.

When food is scarce, the larvae may become cannibalistic. The larval stage lasts 8 to 24 days, while the pupal stage lasts 1 to 2 days.

Adult Drain Flies 

Adult drain flies live for about two weeks, during which time they will mate and lay eggs. Adult drain flies feed on flower nectar and polluted water. They also rest in shaded areas or on walls near plumbing fixtures during the day. 

Where do drain flies come from?

university, cycle, figure

Drain flies are attracted to moist, dark places and often come from areas with standing water. For example, they may lay eggs in the film that accumulates inside drains when sewage pools and collects.

Hence homeowners need to keep their drains clean and flowing properly.

Drain flies are attracted to moist environments so that they may be found near:

  • Wet mops and buckets
  • Compost piles
  • Storm drains with standing water
  • Wet areas around garbage, birdbaths, or barns

What Do Drain Flies Eat?

Drain flies are small, dark-colored insects that live near damp areas. They get their name from their fondness for hanging out near drains, where they lay their eggs and feed on organic matter.

When it comes to food, these little critters are not picky eaters. They will munch on just about anything, as long as it is moist and decaying. This includes dead skin cells, hair, food scraps, and even sewage.

While they may not be the prettiest creatures around, drain flies play an important role in the decomposition process. Without them, our drains would be overrun with rotting organic matter.

Step by Step Drain Flies Treatment in Home Infestation

drain fly, moth fly, gardner

To get rid of the drain flies, it is important to identify them. Once you have identified them, you can use various extermination methods. Like:

Step 1: Unclog any drains

Drain flies are attracted to the organic matter that accumulates in drains. They love clogged or slow-moving drains. So, the first step is making sure you take care of these drains first by unclogging them. Ensuring that the water is flowing freely.

Step 2: Clean the drains

To identify and get rid of drain flies, you will need to take the necessary steps. You will need to clean the drains, which means removing decomposing junk.

Use a flexible brush for cleaning. Remember to use a gentle scrubbing motion when removing grime from pipes. It will help loosen any built-up residue.

Step 3: Clean the U-trap

Drain flies will often congregate in the U-trap of your sink. Because that is where the water pools and it provides a hospitable environment for them.

Either pour boiling water down the drain or clean the U-trap with a bleach solution to eliminate these pests.

Step 4: Use an enzyme cleaner (Drano as drain cleaner)

An enzyme cleaner will help break down the organic matter, attracting the flies. It is important to note that you shouldn’t use Drano as it can damage your pipes. Yet it is effective against drain flies.

Instead, an enzyme cleaner provides a softer layer of chemicals that will help get the job done and ensure the passage of grime and particles in the future.

Step 5: Rinse your drain

Once you have located the breeding ground of the drain flies, it is important to eliminate them. Hence, thoroughly cleaning the drain and surrounding area. It would help if you also cleaned any other drains in your house, as these may also be breeding grounds for the flies.

It is important to continue checking your drains for two weeks after cleaning to ensure a significant decrease in the number of flies.

How To Get Rid of Adult Drain Flies (Moth Fly/Sewer flies)

graphic, ant, woman

There are a few ways to take care of adult drain flies. The first is to identify them in different states and materials. Then, you have identified the adult drain fly and the source of their numbers in question.

Adult drain flies don’t make more eggs or larvae. So taking out the adult drain fly is next on the list.

There are a variety of methods you can use to take care of adult drain flies, including but not limited to: insecticides, traps, and natural predators. Different products can be used as drain cleaners, like:

Fly Swatter

A fly swatter is an effective tool for catching sewer flies. It is important to be aware of the differences between flies, as some are easier targets than others. In the case of drain flies, they get easily caught on the wall. You can do it by maneuvering the swatter to catch it.

Dish Soap and Warm Water

Drain flies can be a nuisance and are often difficult to get rid of. One way to kill them is by using dish soap and warm water.

In a spray bottle, mix 2 cups of warm water and seven drops of dish liquid. When you spot a fly, spray them with the mixture until they are covered. It will kill them instantly.

Soap, Vinegar, Sugar, and Water

This DIY remedy is one of the most popular and easiest methods. All you need is some soap, vinegar, sugar, and water. Mix these ingredients in a spray bottle and use it to spray the areas where you see the most flies.

The soap will kill them on contact, while the vinegar will help to repel them. The sugar attracts them, and they will drown in the water.

Baking Soda + Salt + Vinegar

There are many ways to get rid of drain flies, but this is one of the most natural methods. You will need baking soda, salt, vinegar, and boiling water.

Mix all of the ingredients and pour them down your drain. Let the mixture sit overnight and flush out the pipe with boiling water in the morning.

Apple Cider Vinegar + Plastic Wrap

One way to trap them is to use an apple cider vinegar and plastic wrap fly trap. Cover a container with plastic wrap and poke small holes in the top. Fill the container with apple cider vinegar, ensuring the flies can get in, but they can’t get out.

Drain + Duct Tape

Use duct tape to seal off your drain overnight. Then check the tape in the morning for fly eggs. You can also use our detection method to use a vinegar trap. Sealing off the drain will keep the flies and help you quickly get rid of them.

Drain flies control

Moth fly or drain fly (Clogmia albipunctata)

Drain flies are not harmful to humans but may become a nuisance. They can be found in large populations of houses and restaurants.

While they do not typically carry any diseases, they can contaminate food and spread bacteria. To get rid of drain flies, one must first identify the breeding ground and then take steps to remove it.

Preventing drain flies is necessary. If you have a drain that goes days or weeks without use, close it up with a stopper so that they cannot find a home there in the meantime.

Drain flies’ presence often indicates an issue with the drainage in your home. For good control of drain flies, larva breeding sites will need to be eliminated. It can be difficult to drown them because they trap air bubbles.

Do drain flies bite?

Do drain flies bite?

Although drain flies don’t bite, they are still problematic. They tend to fly around your head and can be a general annoyance. No one enjoys having bugs in their house, so take preventative steps to eliminate them!

Are drain flies harmful?

Moth fly, Psychoda grisescens, Satara, Maharashtra, India

Drain flies are generally harmless to humans. They typically live in moist environments such as drains and garbage disposals. While they can contaminate food, they are not known to carry any diseases.

Drain flies can be a nuisance in homes and businesses as they reproduce quickly and spread nests throughout pipes. If left unchecked, these pests can cause extensive damage that will cost homeowners or business owners money to clean up.


Drain flies are attracted to pools of water that contain sewage and organic material. Make sure your pipes are clean and flushed out often with water to stop them. In more serious situations, you may need to use a cleaning solution every day to keep an infestation from happening.

Drain flies can be a nuisance and are often difficult to get rid of. If you think you have drain flies, look for early signs such as their larvae, which are black and look like a small worms.

About the author

A biotechnologist by profession and a passionate pest researcher. I have been one of those people who used to run away from cockroaches and rats due to their pesky features, but then we all get that turn in life when we have to face something.