Pest Control

The Complete Guide To Getting Rid Of Drain Flies

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Hubert Miles

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Drain Fly

Everyone has had a fly buzzing in their ear, making them feel like they are losing their mind. When it comes to an infestation of drain flies, you’ll feel like your sanity is at stake. Luckily, we will break down everything you need to know about getting rid of drain flies.

There are many natural and chemical solutions to dealing with these insects. Drain flies have a high reproduction rate and can establish multiple breeding sites on your property. These flies are attracted to stagnant bodies of water, especially in plumbing pipes and sewage systems. The organic waste in these pipes is where drain flies lay their eggs.

Whether you’re battling drain flies or want to prevent them from moving into your home, we’ve broken down everything you need to know. In this article, we will start by looking at the biology of drain flies, how to identify them, and why they have infested your property. After this, we’ll look at methods to locate their breeding sites and natural and chemical solutions to eradicate them.

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What Are Drain Flies?

Shakespeare famously wrote, “a rose by any other name would smell as sweet.” Well, a drain fly by any of its other names would still be as much of a pest. This type of fly is known by many names, including sewer flies, moth flies, sink flies, filter flies, and sewer gnats.

Scientifically, these flies belong to the Psychodidae family. No matter which names you know these pests by, if you’re reading this article, you are looking for the best way to get rid of drain flies.

People estimate that more than two thousand different species of drain flies are currently in existence. The name ‘drain flies’ comes from the typical breeding ground for these pests.

These flies are known to occupy sewerage systems and plumbing drains. Given that almost every building in the world has some plumbing and sewage system, these flies are a widespread problem for people worldwide.

To effectively deal with a drain fly infestation, you must understand how these flies operate and function. Once you know these flies’ biology and reproduction cycle, it will better equip you to prevent and eradicate these flies.

To this end, we’ll explain what you need to know about drain flies in their biology and reproduction, how to identify them, why you’re seeing them appear, and whether or not they pose a threat.

Where Do Drain Flies Come From?

In general, a drain fly’s lifespan can last between 8 and 24 days. While this may seem like a short lifespan, waiting for these flies to die naturally is not an option. Twenty-four days is a long time; within just two days, a drain fly can lay more than 300 eggs.

As you can see, dealing with a drain fly infestation is crucial and should be done promptly. Ignoring these pesky insects could lead to them becoming an exponentially bigger problem.

However, if you don’t deal with drain fly infestation, it could lead to more nests for these flies in your drainage pipes. This could make coping harder the longer you wait. If you spot drain flies flying around, you’ll want to deal with them quickly.

Reasons You’re Dealing With Drain Flies

When it comes to these annoying insects, you might be wondering why they’re bothering you in the first place. There are important reasons why you’re battling drain flies. Understanding these reasons will better equip you to win your battle against these common pests.

The main reason you’re spotting drain flies in your space is a stagnant or stationary body of water nearby. These flies are particularly attracted to areas like plumbing drains, sewage systems, and septic tanks. However, other stagnant bodies of water can also draw these flies and provide them with the appropriate breeding environment.

These flies can also feed on organic matter built up in drainage pipes. This is another crucial factor in what attracts these pesky flies to your sewage system. Typically, these flies breed areas also provide some food supply through sewage remains.

You may also attract these flies to areas with accessible garbage, animal waste, and even fertilizer or compost. 

How To Identify Drain Flies

Drain flies can easily confuse with other flies, such as fruit flies, due to their size. Drain flies are typically between two and five millimeters or about 1/8th of an inch long. However, we’re not suggesting you break out your ruler to determine whether you have drain flies. In the next section of this article, we’ll look at different ways you can definitively tell if you are dealing with a drain fly infestation.

Before we do that, you’ll need to know what these flies look like when determining if you have drain flies. In addition to their length, there are other simple ways to identify these flies. Firstly, these flies have antennae, a pair of wings, and six legs. Their bodies are typically light gray in appearance, while their wings are covered in long, fine hairs.

The hairs on the wings of these insects are the reason they are also known as ‘moth flies.’ This is why you sometimes confuse a drain fly for a flying moth or vice versa. Luckily, there are ways to determine if you are battling drain flies, and we’ll get to those in a minute.

Do Drain Flies Pose A Threat?

The short version is that drain flies are only a threat to your sanity. Overall, these annoying flies do not carry any diseases and do not pose risks to your health.

However, left unchecked, these flies will become more of a nuisance to you. Given their reproduction rate and how they can establish multiple nests, drain flies can become a bigger and more expensive problem to deal with. That’s why you’ll want to deal with them in the most efficient ways possible!

Where To Begin When Dealing With Drain Flies

Before getting rid of drain flies, you need to locate them and ensure they are drain flies. Finding the lairs of these flies is half the battle! Once you’ve discovered their breeding spots, which they can hide in surprising locations, you’ll be ready to remove them permanently.

You may see fruit flies around your garbage and confuse them with drain flies. Phorid flies are also known for being attracted to areas contaminated with sewage.

You want to ensure that you’re dealing with drain flies! That way, you won’t waste time or money on incorrect coping with the specific type of fly bothering you. Luckily, you can use a couple of methods to quickly determine whether you are dealing with a drain fly infestation. The first method goes right to the source: the drain.

Duct Tape

The Duct Tape Drain Test For Drain Flies

This is one of the most common methods discussed across online forums and articles. This tried-and-tested method of checking for the habitation of these flies in your drain is sure to help you.

If you follow the instructions, you’ll have an answer within a couple of hours. Once you’re confident about what type of fly you’re dealing with, you can proceed using the appropriate methods.

Step One: Get Some Duct Tape

You’ll want to ensure you use duct tape with sufficient stickiness for this drain fly test to work correctly. You can test this by touching a corner of the duct tape to ensure it will work.

Step Two: Duct Tape Your Drain Closed Overnight

You’ll want to seal your drain overnight with the duct tape you have chosen to use. When you wake up, you’ll be able to determine whether you drain flies or not. The logic is simple: the drain flies will try to come out of the drain to the outside but will get trapped on the duct tape you used to seal off the drain.

Step Three: Check The Results Of Your Duct Tape Test

The morning after you seal off your drain with duct tape, you’ll want to check the duct tape. If you are dealing with drain flies, they will have gotten stuck on the duct tape.

This confirms that they have likely laid eggs within your drainage system. If you do not see any flies on the duct tape, you may be dealing with a different type of flies or no flies.

If this test did not yield the results you were expecting and you have a hunch that you are dealing with drain flies, there’s another test you can try yourself at home.

If this test proved you are dealing with drain flies, you’d also want to use the following test to determine the various breeding sites these flies originate from.

Drain Flies

Locating All Drain Fly Breeding Sources

Due to drain flies having a high reproduction rate, the breeding sites of drain flies can often be located in numerous locations across your property. For this reason, you’ll want to discover all the relevant breeding sites of these flies.

Failure to do this will result in the remaining breeding sites continually developing and spreading. Thus, you’ll be stuck dealing with these pesky insects constantly without reprieve!

You want to ensure your check is as thorough as possible to deal with these flies effectively. These are all the places you’ll want to check and what exactly you’re looking for.

  • The drain: As discussed earlier, while outlining the duct tape drain test, the drain is the best place to start looking for these flies. Using a tool or stick, you can inspect your gutters more closely. If there is any build-up of debris or sludge in your drains, use something to examine it.
  • You might spot larvae, which will look like tiny tube-like worms. The sight of larvae is a clear indicator of a fly infestation.
  • Sump pump: Depending on the architectural design of your space, your basement may have a sump pump in your basement. Areas like these are essential to inspect for drain flies or signs of active larvae.
  • Under the shower pan: Drain flies often develop in bathroom drains due to the sewage from those pipes. You’ll want to inspect those specific pipes closely. You may even want to check under your shower pan a waterproof barrier shaped like a pan beneath your shower tiles.

    This is a common breeding place for drain flies due to the present moisture. To test this, you may need to use a drill to create a tiny hole in the shower pan tiles. If drain flies are there, they will escape through the hole and towards the light.
  • You’ll want to check for any small cracks In your bathrooms and kitchen. These could be gaps that drain flies use to find places to breed. Before they are sealed, you must remove any dirt or debris trapped in these cracks. In the following section of this article, we’ll explore the products for dealing with drain flies in various spaces.
  • Inspect any crawlspaces in your home. You might locate a pipe that is leaking in one of your crawlspaces. This could result in a build-up of stagnant water, which can act as a magnet for drain flies who will use the water for breeding.

    Any areas where moisture can collect in your home should be checked, such as storm drains, your laundry room, water that may have accumulated in houseplants, and even a rogue mop that may have been left somewhere while wet.
  • Speaking of storm drains, the outside area of your house is essential. Outdoor spaces are equally important in terms of locating drain fly breeding sites. Particular exterior features to inspect for drain fly breeding sites include compost heaps, garbage areas, air conditioning outlets, the gutters on your roof, and even birdbaths and feeders.

As a general rule of thumb when locating drain fly breeding sites, you should methodically consider your entire home and property in terms of moisture-rich areas. Any area where stagnant water can collect is an area that could allow drain flies to breed.

Even if you do not have a drain fly infestation, you’ll want to ensure that you don’t have any stagnant water that could result in drain flies breeding. Keeping these areas prone to the build-up of water in mind, you can prevent infestations in the future.

If it’s too late to prevent a drain fly infestation and you’re already battling them, you’re not out of luck. With the right products (which could be either a natural or chemical solution) and determination, you can come out on top in your battle against these pesky flies!

The Best Homemade Or Chemical Products To Get Rid Of Drain Flies

When it comes down to dealing with a drain fly infestation, there are several natural or chemical solutions that you can use. You might want to use multiple methods to ensure the complete eradication of these flies from your home. Let’s break down your options for you!

Besides the natural and chemical solutions discussed above, your only other option in effectively dealing with these pests is to use a professional pest control service. These services will send trained specialists to your home to deal with the drain flies on your behalf.

While this is probably the priciest solution of the methods discussed here, it might be necessary for some instances where the drain flies rapidly multiply due to unlocated breeding sources.

Once you’ve used these methods to get rid of drain flies and their nests, you’ll need to be patient to see if it worked. You might have missed some of you spot adult drain flies after at least a week of cleaning your drains and any other possible breeding sites.

If you realize you haven’t fully dealt with the drain flies, go back to these methods and try to be more thorough in your search for them.

Baking Soda

Natural Solutions To Get Rid Of Drain Flies

These are the best natural ways to get rid of drain flies!

Option One: Boiling Water

This is one of the most tried-and-tested at-home methods to yield results. To use boiling water against drain flies, you should pour the boiling water down your drainpipes twice daily for at least seven consecutive days. This will aid in killing larvae and drain flies breeding inside your pipes. If you’re thorough enough, this method can work wonders for you!

Option Two: Apple Cider Vinegar & Dish Soap

Though the combination of apple cider vinegar and dishwashing liquid might not sound delicious, it’s sure to capture the attention of the drain flies bugging you. For this method, you’ll need a cup of sorts. You can recycle a takeaway drink cup for this.

You’ll want to combine apple cider vinegar with a teaspoon of dishwashing liquid in the cup. Once you’ve done this, you’ll want to cover the top in plastic clingwrap, which you’ll poke holes in. The vinegar smell will attract the drain flies, while the soap in the mixture will trap them in the solution.

You can use this method in various parts of your house infested with flies. You can place a cup next to your drains or in your bathroom – wherever needed. This method does not directly combat breeding sites, but it can be a great ally in your battle against these insects.

Option Three: Vinegar, Baking Soda, & Salt

When combined, vinegar, baking soda, and salt form a natural cleaning solution that you can use to clean your drains. This method is similar to option one discussed here. This method can be used for the best results, followed by method one.

Once you’ve combined the above ingredients, you can pour this mixture down your drain. Due to the vinegar and baking soda reaction, this natural solution will reach more places than mere boiling water. Once you’ve left this natural solution in your drain overnight, you can flush your drain with boiling water, as detailed in option one.


Chemical Solutions To Get Rid Of Drain Flies

These are the best chemical products to get rid of drain flies!

Option One: Chemical Drain Cleaners

Suppose you’d like to use something more substantial than just boiling water or a homemade solution. In that case, you can purchase one of many chemical drain cleaning products readily available on the market.

You can use a product like Drano Drain Cleaner in your fight against drain flies. These products come with specific instructions on using them and how often you can use them for the best results.

Option Two: Aerosol Products

As discussed earlier in this article, drain flies can breed in some hard-to-reach areas. These areas include spaces under your shower tiles or behind cracks in the bathroom or kitchen. Using one of the different aerosol chemical products available, you can tackle drain flies breeding in tight spaces.

Using a sanitation foam in an aerosol container, such as Invade Hot Spot, you can tackle the pests hiding just out of reach. The aerosol mentioned above has a nifty nozzle that can reach difficult areas, such as behind cracks. A combination of chemical approaches can work in your favor to get rid of drain flies completely.

Insect Catcher

Bonus Solution to Help Get Rid of Drain Flies

You could invest in one of the various insect traps available on the market. These products can help kill flies around the clock. The previously discussed methods are more hands-on. This option needs to be turned on! This is an excellent bonus method to deal with any pesky flies year-round. There are many options available in terms of these traps. You are guaranteed to find an insect trapping option that fits your budget.


To beat the drain fly, you have to understand the drain fly. These creatures can reproduce at a high rate and can thus multiply exponentially if not dealt with effectively. Therefore, you want to know everything you can to help you get rid of these pesky pests. This includes information on how they reproduce, why you’re seeing them appear, and their most common home breeding sites.

The first step to effectively dealing with a drain fly infestation is locating their breeding sites. Due to their high reproduction rate, these insects can establish multiple nests around your property. Therefore, you want to discover all of them to get rid of them permanently.

To do that, you can use various natural homemade solutions or chemical products to deal with these household pests effectively. Using a combination of the methods discussed within this article, you’ll be able to deal with a drain fly infestation in no time.

Do You Need Pest Control Service?

Get FREE quotes from licensed pest control technicians in your area today. Whether you need spraying for ants, roaches, spiders, ticks, mosquitos, or bed bugs, We Can Help! All technicians are screened, licensed, and insured.

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Photo of author

Hubert Miles

I've been conducting professional home inspections since 2002. I'm a licensed Home Inspector, Certified Professional Inspector (CPI), Certified Master Inspector (CMI), and FHA 203k Consultant. I started to help people better understand the home inspection process and answer questions about homeownership and home maintenance.
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