Drain flies (Psychodidae) are a diverse family of true flies. They often inhabit household sink drains and feed on accumulated sludge buildup. For that reason, they’re one of the most annoying pests for any home or business. So, how do you get rid of drain flies?
The best way to eliminate drain flies in your home is by first eliminating their breeding areas. This includes drains, sewage pipes, open garbage areas, and yard waste. Indoors, you can utilize various flying insect traps. Then, it’s just a matter of preventing drain flies from returning.
Ed has been working in the pest control industry for years helping 1,000's of homeowners navigate the world of insect and rodent management. He manages Pest Strategies now helping homeowners around the world!
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If trying to exterminate drain flies on your own becomes too challenging, we recommend Orkin, Terminix, and Aptive. These exterminators have some of the best trained professionals that are able to use traps, baits, and other chemically treated solutions that are often more effective than standard DIY methods.
In this extensive guide, you’ll discover the tricks the pros use to eliminate drain flies from almost any environment. Then we’ll tell you which exterminators are the best for helping you solve your pest problem. And finally, we’ll answer some of your most pressing questions about drain flies and other annoying pests.
What Are Drain Flies?
Drain flies are also known as moth flies due to some species having moth-like fur on their bodies. However, there are several varieties within the family of drain flies. And not all of them have this moth-like feature.
Adult drain flies are between 1/5 and 1/6 inches long. Due to their tiny size, they are often confused with fungus gnats and fruit flies.
However, drain flies have different coloring and body shapes than the others. And most species of drain flies are either dark brown or black.
Life Cycle of the Drain Fly
The drain fly has four life stages. They are:
Females lay their eggs in moist areas containing decomposing material, usually In drains, sewers, and other suitable breeding grounds. They hatch within 32–48 hours at temperatures above 70°F. Then, the larvae feed on these gelatinous substances and sediment buildup, and mature within 9–15 days.
Next, the pupal stage lasts for about 20–40 hours until they emerge as adults. After that, the entire lifecycle takes about two weeks. And adults will live about two weeks afterward.
Habitat and behavior
Drain flies don’t just infest drain areas. They also prefer:
- Drain pipes
- Garbage cans
- Septic tanks
- Yard mulch
- Underneath shower pans
- Sump pump areas
You can sometimes spot larvae climbing walls or around shower drains. As adults, they often emerge in swarms. These high numbers signify that the reproductive cycle is at its peak, usually in the spring and summer months.
Signs and Causes of Drain Fly Infestation
There are several signs of drain fly infestations around your home. Here, we uncover the most common ones.
Increased activity indoors
If you suddenly notice a higher number of drain flies indoors, it could mean there’s an infestation somewhere in your home. Although fruit flies aren’t usually aggressive, they sometimes display a high activity level.
Adult male drain flies typically emerge before the female. The highest point of activity occurs during the spring and summer months.
Males swarm to attract females. As a result, there could be thousands in one location. Then, once paired up, the female lays her eggs, and the lifecycle begins again.
Causes of Drain Fly Infestations
Many causes of drain fly infestations may be obvious. However, some may not. So here we dive deeper into why you may be seeing more drain flies in and around your home.
- Dirty drains. Drain flies prefer an environment where there is a lot of sludge buildup. These layers of organic material accumulate over time. And then it gets to the point where drain areas in your home become magnets for drain flies.
- Open drain pipes. The buildup of organic material in open drainpipes attracts flying pests. In addition, the combination of moisture and decaying matter in open plumbing is a strong attractant for drain flies.
- Unsealed septic tanks. Drain flies love areas around septic systems. So, if your cover is even slightly open, they will find a way in.
- Open trash areas. Rotting garbage attracts all sorts of flying pests. Drains flies find it especially appealing if it has decayed enough to form a thick sludge.
- Yard mulch. Decomposing yard waste can be attractive for some types of drain flies. However, what matters most is the time it has spent rotting away. For the drain fly, the longer, the better.
How to Get Rid of Drain Flies
Eliminating drain flies starts with a thorough inspection of all possible harborage areas. Then, it’s time to eliminate all those breeding spots. And finally, it’s vital to prevent this nagging pest by utilizing proactive control measures.
Here are the most important steps to take for getting rid of drain flies:
1. Clean your drains
The first step to ensuring you get rid of drain flies is to clean the sludge from your drains. There are several methods to do this. Here are some ideas:
Hot water can help loosen some of the surface debris and make drains flow better. However, use caution when using boiling water. It could harm your PVC pipes over time, especially if you’re using it to remove clogs.
If you decide to go the boiling water route, it’s wise to limit it to once a week. Also, it’s best to use less than about 16 ounces at a time. However, this amount should still be sufficient to kill any developing larvae.
Baking soda and vinegar
One of the best DIY methods for cleaning household areas like drains is baking soda and vinegar. First, pour about 1/2 cup of baking soda in. Then, follow it with about 1/2 cup of vinegar— white vinegar usually works the best.
This mixture helps to remove built-up grime in your drains and plumbing. Leave it overnight for the best results. It will also keep your pipes from smelling bad.
Chlorine bleach has its place as a cleaner and deodorizer for bathroom drains, kitchen sinks, and floor drains. However, using it too often can harm your home’s plumbing. Also, it’s best to flush the bleach thoroughly from pipes after about 15 minutes of use.
Enzyme drain cleaners
Lipase enzyme cleaners work well to remove grease, food, and sludge from your drains. Most utilize a natural ingredient like citric acid. However, these are powerful cleaners, so be sure to read the label directions before use.
One of the most cost-effective methods to clean your drains is with a pipe brush. It works well when used with drain cleaners. Or it can help with the rinsing process by scraping any stubborn particles left on the pipes.
Some of these brushes come with a long, flexible wire so you can reach far into the plumbing. This will help remove grime from otherwise remote areas.
2. Repair water leaks
Puddles under your sinks can cause drain fly infestations. The combination of moisture, mold, and rotting food sources can become breeding areas. So, it’s a good idea to repair leaky plumbing to keep that from happening.
Leaky shower pans can also present a problem. Drain flies are drawn to the dark, warm area underneath the shower. In this case, you want to either repair the leak or replace the shower pan.
Also, don’t forget outside plumbing leaks. These could also cause infestations of flying insects. And they provide breeding areas as well.
3. Other sanitation measures
Drain flies don’t just breed indoors; they’re truly outdoor pests. They infest anywhere there’s moisture combined with decomposing, solid waste material. For example:
- Septic systems
- Sewage treatment plants
- Outdoor drain pipes
- Stormwater drains
- Outdoor garbage areas/dumpsters
- Air conditioning condensate pipes
It’s vital to keep septic tank covers secure at all times when not performing maintenance. Also, be sure to repair any lines in the system that can cause leakage. Lawns contaminated by sewage will attract all sorts of pests, including drain flies.
Cleaning, repairing, or replacing drain pipes will help ensure you keep drain flies at a distance. In addition, it’s crucial to keep trash containers sealed as much as possible. Also, be sure to limit the amount of moisture in these areas.
4. Trapping for drain flies
When getting rid of any flying pests in your home, there’s no better way than using traps. With most of them, there are no chemicals involved. And they are usually safe around children and pets.
First, throw some rotting fruit into a glass bowl. Now, cover it with plastic wrap. Then, poke small holes in the plastic with a toothpick or sharp knifepoint. Finally, place the bowl near a sink or shower area to draw the drain flies out.
When they smell the pungent odor of the fruit, they won’t be able to resist it. They’ll climb in through the tiny holes to access it. However, they won’t be able to find a way out and eventually die of suffocation.
Apple cider vinegar trap
Apple cider is a strong attractant for most flying pests. That’s why this trap works so well for drain flies, gnats, and fruit flies.
To make the trap, use a small open container like a dish or a bowl. Combine one tablespoon of apple cider vinegar, one tablespoon of sugar, a half cup of water, and three drops of dish soap. Now, stir the mixture well.
Leave several traps in humid environments such as kitchens, bathrooms, and laundry rooms. Once lured, the drain flies will land on the mixture and become trapped by the dish soap.
Candles sometimes attract flying insects. And drain flies are no different.
For this trap, you’ll use a cake pan filled about halfway with water. Next, add about three to four drops of dish soap. Now place a small candle in the middle and light it.
Use several taps throughout the home. Then, when drain flies come to investigate the candle, one of three things will happen:
- The insect will get close enough to the candle and burn up
- The insect will get overheated and fall into the water, eventually drowning
- The insect will be attracted to the water and get caught in the dish soap
Flytraps can work for drain flies if positioned properly. They typically come with a glue board attached to a string.
You can hang these traps anywhere. But, for best results, position several throughout your home to catch gnats, mosquitoes, and house flies.
Electronic UV light traps
5. Environmental control
Most flying insects hate cool, dry climates. So, why not create that environment in your home?
The most important consideration is temperature. Drain fly larvae develop better in temperatures above 70°F. Therefore, to limit infestations, it’s best to bring temperatures down below that.
Also, you need to lower humidity levels. Consider a dehumidifier in the summer. Better yet, invest in a quality central air unit that will lower both temperature and humidity in your home.
If that’s not an option for you, consider increasing air circulation. Be sure to utilize ceiling fans throughout your home. Also, turn on bathroom fans when taking a shower to minimize humidity levels.
6. Spray treatments
We don’t recommend spraying indoor areas with an aerosol spray for drain flies. It will probably not have much effect. And it could contaminate food.
However, outdoor treatments may have some limited use when it comes to drain fly management. Most have an excellent residual effect for long-term control and depending on the formulation, outdoor spraying can limit insect breeding for a wide range of flying pests, including drain flies.
Be sure to treat grass areas where decaying material may accumulate. Also, perform a perimeter barrier treatment for overall protection from pests. And finally, be sure to spray around window and door sills to keep out flying insects.
Drain flies prefer an environment where there is a lot of sludge buildup.
In addition, the combination of moisture and decaying matter in open plumbing is a strong attractant for drain flies.
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How to Prevent Drain Fly Infestations
Preventing future infestations is not all that difficult. It just takes some willpower and planning on the part of every homeowner. So, that’s why we’ve provided this checklist to help you keep drain flies from invading your home.
- Monitor pest activity. Place some clear packing tape on each drain where you’ve previously had problems. Then leave it overnight. If you have drain flies, you’ll know since they will be stuck to the tape.
- Keep drains clean. It’s a good idea to clean drains regularly to keep sludge from building up in pipes.
- Check for water leaks to ensure you aren’t causing ideal breeding environments for drain flies.
- Remove decomposing mulch and grass clippings from your yard.
- Prevent standing water sources by removing old tires and other debris from around the outside of your home.
Top Pest Control Companies for Drain Flies
If you want help with your drain fly problem, it’s possible to hire a pest control company. However, not all of them handle flying insect infestations. Here are three that do.
- Terminix will get rid of mosquitoes, sink flies, gnats, and drain flies for you. They will do so utilizing their legendary customer-first approach.
- Aptive Environmental may be the youngest company of the three, but its track record is impressive. With their focus on results, it guarantees that your drain fly problem won’t return.
- Orkin shines as the leader in commercial pest management by providing businesses with a wide range of services. One of those is fly and mosquito management that’s been proven effective for over 100 years.
Drain Fly FAQs
Are drain flies harmful to humans?
Since drain flies don’t bite humans, scientists believe they are not vectors for disease. However, they do sometimes transmit parasitic conditions such as myiasis to animals through open sores. They do this by burrowing into the wound and infesting it with their larvae.
How long does it take to get rid of drain flies?
Once you remove the drain fly’s breeding ground and food source, the infestation can go away almost instantly. However, the problem remains of how widespread this pest really is. Since it lives with humans, it has almost an unlimited supply of resources available to survive.
Does Drano kill drain flies?
Drano contains chemicals, including bleach, that kill drain flies on contact. However, it’s not the most cost-effective method for eliminating them. So, it’s best to use Drano strictly to unclog sinks.
What smells do drain flies hate?
Like so many other species of flying insects, drain flies hate the smell of what humans find attractive. Here are some examples:
In most cases, these scents are packaged as essential oils that have a wide range of uses. For example, many natural pesticides contain these ingredients to repel insects and other pests.
However, most of these don’t belong in your drains. Therefore it’s important to read the label directions carefully before using these products.