Drain flies, also known as filter flies or sink flies, are small, moth-like insects that live and breed in areas where stagnant water or bacteria gather over time.
Places like your sinks, shower drains, bathtub drains, contaminated soil, exposed sewer lines or septic tanks, etc. They are complicated to deal with because of how quickly they can propagate. In less than 48 hours after their first appearance, you might start seeing more flies.
As with most household pests, they are not impossible to deal with once you understand them, how they work, and what strategies, prevention methods, and removal methods work.
How to identify drain flies
When you have a drain flies infestation, you’d typically find them hanging out around the wall tiles, access points, or hovering over the drain themselves. They typically appear around bathrooms, sinks, guestrooms sinks, and showers drain that are infrequently used.
Drain flies are physically different from most household insects or pests. They are less than 1/8 of an inch, around the size of fruit flies or gnats. They have gray or brown light-colored wings and leave a powdery substance when they’re crushed. Because of this residue, they are sometimes referred to as moth flies–their fuzzy appearance also being the second reason.
Drain flies have patterns or veins on their wings and fly in a strange and almost unpredictable pattern. Drain flies have a short life cycle of 24 hours, but they work really fast in that short time. If you don’t eliminate them in 24-48 hours, you could have as many as 300 new flies on your hand.
Drain flies do not bite or sting. They more or less stick around drains. However, to be sure, check around other areas of your house too. If you find flies hovering around your fruits or biting you, you might be dealing with fruit flies or some other type of pest.
Although bathroom drains, kitchen sinks, and other drains in your home might be the most common places you find them, and you might also find a drain fly infestation around wet mops and buckets, compost piles, storm drains with shallow water, and wet areas around barns, birdbaths, etc. Any place with low, stagnant water is a prime breeding ground.
Tests that help you identify drain flies
Here is a quick tip that lets you know if you have drain flies buzzing around in your pipes or drains.
If you’ve only seen a few flies so far but are still unsure what kind of pest you’re dealing with, this is a simple way to identity drain flies.
1. Duct tape Test
Before you go plotting how to kill drain flies, use this simple duct tape test first. It might save you a lot of time. Duct tape your drain and seal it off overnight. Drain flies like to come to the surface when they hatch, and when they do, they’ll get stuck on the tape.
If you notice more than a few drain flies on the tape in the morning, you’ll have a serious drain fly issue. Armed with that information, you can then plan how you’ll get rid of your drain flies. This confirmation method also doubles as a rudimentary way to get rid of drain flies. You can pair it with other methods we’ll discuss later on to get the best results.
2. Check for Larvae
Drain flies lay eggs in the gunk and organic materials that build-up at the opening a drain over time. To identify if you’re dealing with drain flies, open your drain cover, remove the gunk you see and search for small larvae. They usually have long tube-like bodies and now have wings.
This method is not full proof. If you don’t find larvae at the very edge of your drain, the larvae could be deeper within your pipes.
How do I permanently get rid of drain flies?
Depending on the drain fly infection scale, you can decide to use chemicals or use household solutions, using materials you already have available to you.
Common household solutions for removing drain flies
There are a couple of relatively simple methods and solutions you can use to get rid of drain flies that cost you nearly no money and very little time.
1. Flushing your toilet or drain
Sometimes it might be just as simple as flushing your toilet and removing drain fly larvae and eggs from the stagnant water. It might be enough to discourage them from staying at the drain. It is a relatively great preventive tip, even if it’s not enough to remove drain flies from your home. By flushing standing water regularly, you make sure the water is not stale enough for drain flies to move in.
2. Boiling water
This is another low-budget, highly effective way to get rid of drain flies from your drains. Pour boiling water down the infected drain once or twice a day for a full week. The flies will not return because the water won’t contain enough organic bacteria for them to feed on and breed in. If you’re feeling really paranoid, you can pour boiling water.
3. Mix baking soda with Salt and Vinegar
Create a great drain cleaner by creating a mix of baking soda, salt and vinegar, and pouring it down your drain. Overnight, the baking soda will cause the vinegar to expand and allow it to reach more places it would have if you poured only a cup of vinegar. Let it sit till the morning and flush it out with some boiling water.
4. Apple Cide Vinegar and Plastic wrap
You can make a fairly good drain fly trap by covering a bowl with some apple cider vinegar in a clear plastic wrap. Make some holes in the top of the plastic wrap with a staw, and you have a functional fly trap. The holes will allow them to get in but not fly out, and the vinegar will kill them.
5. White vinegar, salt, and baking soda
Another alternative recipe you can try is 1/2 a cup of baking soda, 1/2 a cup of salt, and a cup of white vinegar. Pour it down infested with drain flies. Flush it and clear out the mix with another flush of boiling water. This mixture will help clear out your drain, kill drain flies eggs, and make your drain unsuitable for future habitation.
6. Clean out the drain with a metal drain brush
You can use a metal drain pipe brush and some soap to clear out the water in your drain. After using the brush, follow up with copious amounts of boiling water.
7. Trap them with a combination of water, vinegar, and liquid dish soap
Make a homemade trap with a clear bowl and plastic wrap on top. Add sugar water, vinegar, and 5-10 drops of dish soap.
Getting rid of drain flies using chemicals
After exploring the non-chemical ways to get rid of drain flies, you might be interested in more potent and speedy options. When using chemical cleaners and repellents, make sure to read through the instructions and understand them before you apply them. Also, please don’t mix them with other drain fly or pest control products.
Traditional drain cleaners
Traditional drain cleaners are typically used with warm water and a pipe brush to clear outstanding water properly.
Traditional drain cleaners are not all chemical-based. Many products use all-natural ingredients to help you fight your drain fly infestation.
Chemical sprays and repellents
Most chemical sprays and pest control solutions are not designed to combat gnats and fruit flies specifically, but they work just fine for drain flies too. They sometimes contain caustic acids, so you have to be careful when applying them to your kitchen drain. Use too much, and they can damage your pipes.
How to prevent drain flies
After removed them from your home, you should focus on preventing another infestation by adopting a few habits that’ll keep them away in the future.
The easiest prevention tip is to clean out your drains and flush them regularly with regular water, hot water, or cleaning solutions. If you go weeks or days without using a drain in your home, close it up with a stopper so that drain flies can’t gather around it overnight and lay eggs.
Aside from proper drain sanitation, it would be best if you kept your home tidy at all times. Keep an eye out for dirty mops, abandoned buckets, and maintain a healthy septic system overall.
Another great tip to prevent a full infestation is to inspect your home when you see drain flies buzzing around. Check your kitchen sink and other breeding grounds so you can get ahead of the infestation. Remember to check around your home for flies too.
When should you call a professional?
Drain flies are fairly easy to deal with if you have enough time on your hands and follow any of the remedies suggested.
However, if you have neither the time nor experience of insect or press control, you can call professional pest control agents to help you eliminate the flies from your home. A great benefit of going with a professional is that they have enough experience with drain flies to help you easily identify the source in case you’re having trouble finding it yourself. They can also more easily identify the insect.
Frequently asked Questions
Here are a few of the frequently most asked questions homeowners have about getting rid of drain flies.
Will bleach kill your drain flies?
Yes, it will. Pouring bleach down your drain and following it up with some warm water will clear out your drain of flies, but it’s recommended that you don’t. There are faster, less caustic ways of destroying their eggs and removing them from your home permanently.
Will drain flies go away?
Drain flies love areas with standing water, and by cleaning it out, you’re cutting off their food source. Without it, they will eventually die out within 24 hours or so.
However, without taking any preventive, DIY, or extermination efforts, Drain flies rarely go away on their own. Some flies can survive through the winter if your pipes are warm enough.