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Best Drain Fly Killers [UPDATED 2021]: a Drain Gel, Foams & a Brush | Best Ways to Eliminate Sewer Flies from Your Life | Buyer’s Guide

My friends say that I have succeeded in getting rid of drain flies just because I am a professional entomologist. Well, my expertise, of course, played its part but it was my unique personal experience that made me win over those filthy pests. So I created this guide to share my experience and knowledge with those who are still struggling to do away with them. Here you will learn what attracts drain flies and how to remove them from the house.

How to Get Rid of Drain Flies | Best Drain Fly Killers Infographics |

What is the best drain fly killer?

1. InVade Bio Drain Gel
This natural solution based on citrus oil and beneficial microbes works great against drain flies. It is safe and can be used daily. Four ounces are enough to clean one drain.

InVade Bio Drain 1 Gallon min: photo

2. Drain Brush to clean pipes
This bendable brush will unclog any drain. With a length of 48 inches, it can eliminate the toughest blockades. While being very flexible, it comes with firm bristles.

Extra Long Super Flexible Drain Brush min: photo

3. Gentrol Insect Growth Regulator to prevent breeding
The product is labeled for use in drains. Based on Hydroprene, it sterilizes insects, preventing larvae from developing. Apply the foam to both cracks and flat surfaces.

ZOECON Gentrol Insect Growth Regulator min: photo

4. InVade Bio Foam for hard-to-reach places
The solution contains citrus oils and microbes that eliminate foul smell. Use it under appliances, in drains and smelly spots. The foam dissipates within 2 hours.

InVade Hot Spot Bio Foam min: photo

What You Will Learn From This Guide:

How to Get Rid of Drain Flies in 8 Steps

Before starting to do anything, I developed a plan which I consistently followed. Here it is:

Step#1. Inspect all the pipes to see whether they are leaking. Clean dirty garbage cans, remove stagnant water under plant pots. Look for any leakage outdoors, in particular, in such places as beneath air conditioners or bird baths. In other words, any natural or artificial container with stagnant water should be removed or emptied.

Step#2. Detect the source of the problem. Since these pests are nocturnal, there is nothing to do but set traps that will show what kind of creatures and where exactly dwell. To this end, you should know how to trap drain flies in a proper way.

Actually, there is no rocket science here. Take a clear plastic container with one or more glue boards on the sides. Place it upon the opening that the pests are supposed to inhabit. Be patient and leave the trap for the whole night or, even better, for several nights. Another solution involves using a plastic cup greased with vegetable oil or petroleum jelly. If you have drain flies trapped, congratulations — your house is infested!

Step#3. Destroy their world. Namely, the gelatinous slime on the inside surface of the pipes. But keep in mind that drain cleaners may not help because they are designed to remove clogs rather than slime. The best method of removing slime is cleaning the pipe with a plumber’s snake. But do not be lazy, do it thoroughly! Or you may take any wire brush, as long as it is flexible and long. Like Brushtech Drain Brush that is 48 inches in length. Being stiff, it bends easily and goes deep into the drain. A cost-effective and viable option that is always useful to have at hand.

Brushtech super flexible drain brush: photo

Step#4. If the infestation is not severe, pour hot water down the drain. In any case, I would not advise you to use this method because it is effective only in a short period of time. The thing is that drain fly larvae are hard to drown because of their unique ability to trap air bubbles and stay underwater for many hours.

Rockwell Labs IBDC032 Invade Bio Drain Gel: photo

Step#5. Apply special-purpose products — drain cleaners like InVade Bio Drain Gel — that are commercially available. Scientists from Ohio State University say that the best solution is using enzyme-action products. They are made to break the sticky bond formed on the pipes or better known as the scum. Nor should you pour insecticides down a drain as this will not kill the larvae but can damage the sewer.

Insect Growth Regulator: photo

Step#6. Spray insect growth regulators into the drain. This will not kill the adult insects but will prevent them from laying eggs. While larvae affected by IGRs will not be able to develop further.

Step#7. Kill flying adults. You can do it in two ways. The first one adds a bit of amusement to the process of killing drain flies. I mean fly swatters and my choice here is an electric bug zapper. The second option is spraying the insects with aerosols. However, bear in mind that both methods just knock down the flying insects and do not eradicate the larvae.

The Revolutionary Tub Drain Protector Hair Catcher: photo

Step#8. Once you have eradicated the drain fly infestation, think about what can be done to prevent their appearance in the future. If these creatures have visited your house once, they can do it again. What has to be done in this case? You need to eliminate the environment that can be turned into their breeding sites.

For example, use TubShroom device that fits inside the drain to collect hair around it. Just for a bit more than ten dollars you get a sophisticated and quite effective tool that fits any standard tub drain. I am not sure that the item will last long as it is made of silicone but you will obviously have to clean the drain more rarely. Another benefit is that water continues to flow when the device is installed and has caught hair.

How To Kill Drain Flies: TOP Best Drain Fly Killers

Applying all sorts of liquid solutions provides a temporary effect but also has some advantages. This will help you to clean hard-to-reach places where a brush cannot get. And not only that, various gels and liquids will kill bacteria and disinfect the pipes and other systems, which is particularly essential for septic tanks.

Below you will find products that will help you remove drain flies from pipes, sewage and septic tanks. I have paid a special attention to the solutions capable of penetrating into the most hard-to-reach areas. These products come in different formulations — gels, foams, aerosols, powders, and liquids — so that you can choose the most convenient for you.

1. Invade Bio Drain Gel For Bathroom | Natural Solution

Invade Bio Drain Gel: photo
Brushtech Super Flexible Drain Brush: photo

It will cost you some fifty dollars. Well, you might want to get something special for that kind of money. The product is based on natural ingredients, mainly citrus oil, and therefore, is safe.

Pour four ounces of the stuff directly to drains but do it regularly, on a daily basis. Re-apply it every day over the course of two weeks and then do it once a week to maintain the effect. This solution will not completely eradicate drain flies, however, their number will be reduced notably. I know people who say the gel worked great in the bathroom which was not frequently used. And don’t forget about Drain Brush!

2. Gentrol Insect Growth Regulator | As Exterminators Use

Gentrol Insect Growth Regulator: photo

This product is more expensive than the previous one but help to solve the problem with new generations of drain flies. The liquid does not kill the insect but rather sterilizes it, making unable to lay eggs and preventing the existing larvae from developing. Using such products would be a wise choice and it is approved by scientists.

You will see the result in the long run but the stuff worths using. Otherwise, you will keep on saying something like “D’oh, I put just as much of myself into cleaning the drain but these filthy insects pop up again in two weeks!”. Use the solution as a preventive measure, spraying drain pipes once a month. A good and effective solution suggested by exterminators.

3. InVade Hot Spot Bio Foam | For Hard-To-Reach Areas

Approximately the same price will cost you InVade Hot Spot, the advantage of which lies in the possibility to penetrate into hard-to-reach areas that are usually located under appliances, in sewage pipes and the like. In my opinion, this is an important quality characteristic.

The stuff contains microbes eliminating odor and designed to clean various surfaces, including these of pipes, from organic substances such as vomit, urine, scum. Spray the solution directly into drain and wait until the foam dissipates. It will take no more than a couple of hours. During this time, you should not run water down the drain.

What are the best solutions for septic tanks

A septic tank is used in places that are not connected to sewerage. As a rule, it is made of concrete or plastic designed and is designed for wastewater to flow through it. The problem with septic tanks lies in the bacterial environment developed inside, something that can become an excellent breeding site for drain flies. Whether special-purpose products can help to maintain the septic system is still an open question. Such solutions can be not just useless but even damaging.

Experts from N.C. Cooperative Extension warns against applying products that are incompatible with septic systems. All the necessary information is indicated on the label, so make sure you read it thoroughly. The wrong product may disrupt the microbial action in the septic tank.

4. Rid-X | For Septic Tank Systems

Rid-X For Septic Tank Systems: photo

For those having septic tanks, I would suggest using Rid-X. The package contains pouches with concentrated advanced enzymes which dissolve in the water and break down grease and other waste in the septic tank. Pouches are convenient as they cannot be scattered, easy to store and use. A downside is the product’s price — given the pouches need to be used permanently, some fifty dollars per package will cost you a pretty penny.

Comparative Chart of the Best Drain Fly Killers

Invade Bio Drain Gel

Based on natural ingredients (citrus oil) and is safe
Brushtech Drain Brush

The most recommended and effective way of removing slime
Gentrol Insect Growth Regulator

It sterilizes the insect so that it cannot reproduce. Prevents the larvae from developing
InVade Hot Spot Bio Foam

Penetrates into hard-to-reach areas under appliances, in sewage pipes etc.
Rid-X Septic Tank System

Specially designed to break down waste in the septic tank. Comes in convenient pouches.

Breeding Sites: Where Do Drain Flies Lay Eggs?

Drain flies need the friendly environment to reproduce and thrive. These are polluted and shallow water or very moist organic materials. The most widespread type of their habitat in our homes is slime and muck which are accumulated inside the sewage systems, septic tanks, air conditioning pipes etc.

It is here that the pests lay eggs and the larvae develop. In other words, this is their world. Breeding sites for drain flies appear in rubbish bins as well as outside the house — all sorts of containers with stagnant water and holes in the tree trunks.

People ask me why drain flies in bathrooms is such a common thing to happen. This is because the bathroom meets their breeding site requirement more than any other room in the house. Moreover, it is there where we usually wash the head and the furry body of the pet. Hairs clogged in the shower drain is something these pests enjoy to live on.

Other sites are the kitchen sink, floor drains as well as all the drains in the room. So it is very important to reveal all breeding sites for drain flies as it will be the prime target in your efforts to eliminate these pests.

Inspection: Where Do Drain Flies Live?

There are two ways for you to learn where they dwell. First, watch where the adult flies. The thing is that they fly poorly and often prefer to bounce. That is why these insects do not fly far away from their breeding site. So if you see the pest on walls near a drain, there is a high probability that this very drain is infested.

Bear in mind that, as a rule, there are several infested drains, not just one. For this reason, you should inspect not only the drain, next to which the flying insect was noticed, but other drains as well even though they do not seem suspicious. To check drains, remove its plate and take some slime from there. In infected drains, the larvae are likely to be discovered.

And yet, you may not find them in the slime, which is not the reason to breathe a deep sigh of relief. Rather, this can indicate that the larvae are much deeper in the pipe. And this is traps that will help you to resolve doubts. I have described above, how to make such traps.

The idea is simple: you take any container with adhesive applied on the inner side. Place it upon the source of concern, i.e.the drain, and leave it overnight. If drain flies inhabit the drain, they will certainly get stuck to the adhesive material. When do drain flies come out? They are nocturnal insects, therefore, the experiment should be conducted at night.

Why Are Sewer Flies Dangerous?

These insects cannot harm people either directly or indirectly. Nor can they damage structures or pipes they are living in. Take it easy, in general, they are just nuisance pests! The problem is that when the bathroom or any other room is crawling with drain flies, something that will drive mad even the most tolerant guy in the world.

Of course, there is a risk that they can bring pathogens from dirty sites to places where filth is unacceptable, such as hospitals or kitchens. In some cases, allergic reactions caused by the dead drain flies were reported. And on top of that, this makes the room look as if it is poorly maintained and there are unsanitary conditions (which often turns out to be true). Still, they remain predominantly nuisance pests.

Sometimes, people are worried that these pests can do something bad to their skin.

Do drain flies bite humans? Relax, man, they do not. In some cases, people’s fears exceed the bounds of reasonable explanation. “Can drain flies lay eggs in humans?” I was asked one day. Well, this sounds like a horror movie. Of course, they cannot… Unless the human vein turns into the sewer pipe.

How Does Drain Fly Killer Work?

You need drain cleaners to eliminate adult insects and destroy their environment in the pipe. In addition to that, they remove unpleasant odor from the drain.

Bear in mind that these solutions are not actually insecticides which cannot be applied to water sewerage systems. The active ingredient of such products is bacteria that, as you can imagine, are able to get into the most hard-to-reach areas of the drain pipes.

Once inside, the bacteria consume slime and other organic material there. When they become saturated, they die. The benefit of these bacteria lies in the fact that without that organic material, there will be no breeding places left for drain flies.

How to use drain cleaners?

The most important thing to realize about drain cleaners is that you are not dealing with chemicals and, hence, they require more time to produce the effect. I suggest that you should apply the cleaner to drains in the evening and for the whole night to allow enough time for the active ingredient to do the job.

Although drain cleaners are not hazardous to people, you should better apply them with gloves on your hands. After the application, wash your hands thoroughly.

How to apply drain gel properly?

Pour it directly into the drain. The volume is specified for each particular product and indicated on its label, but roughly, five ounces will be enough to start with. Pour the gel regularly as it should not be a one-time action but rather a consistent program for destroying the environment for drain flies.

How to apply drain foam properly?

The foams are sprayed, not poured into the drain. But the main difference from the gels lies in the fact that the foams do not start acting immediately. When you spray the solution, it first appears in the form of a foam that requires time to dissipate. As a rule, it takes several hours. Throughout this period of time, you should not turn on the tap or flush the toilet.

Prevention: Correcting Drain Fly Problems

Any insect infestation is terribly hard to eradicate. And I am saying this as a professional entomologist. That is why it would be wise to take care of the drains and pipes beforehand to prevent the appearance of the insects.

The most effective method to prevent drain flies from settling in the house is to regularly clean the toilet, pipes, and any components of the plumbing system. Where there is no organic material or other bacterial scum, the larvae do not have food to develop. Scientists from Ohio State University say that cleaning drains with enzyme-action products would be a wise choice. Clean pipes with a brush not just when they are clogged. Do it regularly to prevent the formation of the environment that will attract drain flies.

Trash cans should be cleaned and emptied very often. Clean dirty garbage containers and empty frequently. Take care that there is no moisture under the washing machine and empty containers with stagnant water under plant pots. Look for pipe leakages outside the house and repair if any are revealed.

When Is It A Wise Choice To Call An Exterminator?

Let’s be honest… The main argument against hiring an exterminator is a jaw-dropping price for “just killing these filthy pests.” I would not say that their job is that easy but I agree that we should think twice before making a decision to pay one more bill (as if our other bills are not enough). So let’s have a look at situations when it is worth calling an exterminator.

First. When the infestation is so severe that you are just about to give up. In this case, you might need more powerful solutions but many of them are of the restricted use and only a certified professional can handle them. Generally, this is about applying insecticides. That is when you will have to hire an exterminator.

Second. When the breeding site is not exposed and is located in hard-to-reach areas. For instance, drain flies can settle within the wall voids or beneath the foundation.

Third. An exterminator can also act as a consultant and can help you to better understand your specific situation. After completing the job, the exterminator will suggest what you should do to fix the result and prevent the pests from settling there again.

What is the best way to get rid of drain flies?

Now, what have I learned from my experience? One can deliver a fatal blow to these insects only by using several methods combined. There should be no pipe leakage or stagnant water outside the house, and there should be clean pipes inside. And these are just conditions for successful pest control.

The real work starts with you being like the plumber and exterminator in one person. Take a wire brush with a long handle and clean all drains. Do it several times to make sure that you have done your utmost. Then pour a drain cleaner and leave it overnight. From time to time set traps to check whether there are any insects left.

And even though you see that there is not any, do not lean back! Once drain flies found their way to your house, they are more likely to do it again. That is why you should always have an effective drain cleaner at hand and use it from time to time.

F.A.Q On How To Get Rid Of Drain Flies

How to get rid of drain flies with vinegar and baking soda?
Baking soda and vinegar will clean the drain and, therefore, destroy the insect’s habitat. You need half a cup of baking soda and a cup of vinegar. The solution will bubble — don’t worry, it is OK. Leave the mixture for about an hour. Then pour hot water there to wash it away.

Can bleach get rid of drain flies?
Do not use bleach because drain fly larvae are resistant to it. More importantly, when applied after a caustic drain cleaner, bleach can produce a gas that is very dangerous for people.

How to get rid of drain flies with essential oils?
Citrus oil, for example, is an ingredient that many producers include in drain cleaners. You can make a solution yourself. Take the oils of clove rosemary, cinnamon, and eucalyptus and pour into the drain. Just a few drops will be enough. After that, cover the opening with a cup so that the oil vapors cannot come out.

How to get rid of drain flies coming from toilets?
Pour a drain cleaner inside. If you use septic tanks, use special-purpose products that are compatible with septic systems.

How to get rid of drain flies in garbage disposals
The insects are attracted to bacteria and food particles formed in the garbage disposal. What can you do? Pour a liquid soap into the drain to wash away leftovers. Then place ice cubes there to remove the remaining food particles and run hot water. Pour half a cup of baking soda and cover the garbage disposal. Leave it for ten or more minutes.

How to get rid of drain flies in washing machines
Wet lint under the washing machine is one of their preferable sites. Use foam cleaners capable of penetrating into hard-to-reach areas.

Can drain flies come from air conditioners?
Yes, these pests breed under air conditioners. If the appliance is not properly sealed in the window, any insect can get inside. Drain flies can get indoors if the air conditioner is faulty. They lay eggs on the sides of condensate pipes for air conditioners.

Can drain flies come through air vents?
They can get into the house through tiny holes and air vents are quite a common entry point for them.

Can drain flies live in walls?
Yes, they can settle in the wall voids. The thing is that there can be leaks within the wall about which you are unaware. You can hardly cope with this problem on your own, that is why you should call an exterminator.

Are drain flies attracted to light?
Yes, they are. These pests can be seen congregating around all sorts of illumination devices. They are particularly attracted by ultraviolet and for this reason, some people use UV-light traps to capture them. Using such a trap, you can catch a number of these pests but this will not resolve the problem.

Are drain flies attracted to food?
It is not food in itself that attracts them but rather the decaying organic matter that forms when food particles start to rot.

Do drain flies die in the winter?
They live in moist and warm places. The temperature should not be below 70 degrees Fahrenheit to make them feel comfortable. If it colder indoors, drain flies would stay hidden whereas winter temperatures would simply kill these pests.

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