Like most things in nature, gnats are an important part of the ecosystem, but nobody wants to share their home with them. Luckily, once you understand what brings gnats into your home, you can take steps to keep them away. But what is it that attracts gnats in the first place?
You can reduce the chances of gnat activity in your home by storing food properly, keeping drains clean, changing garbage cans often, and eliminating areas of standing water from around your house. Gnats are specifically attracted to:
- Certain Scents
- Decaying organic material
Continue reading to learn more about the different species of gnats and what you can do to keep them out of your house for good!
Gnats Are Attracted to Moisture
Most gnats are attracted to moisture because their eggs need it to survive. However, exactly where they find moisture will depend on the species.
Fruit flies often lay their eggs on moist, fermenting fruit or vegetables. But since they only need a thin layer of material to breed, they can also be found in sink drains, trash cans, and empty bottles.
Fungus gnats also need moisture to lay their eggs, and they often find this in the soil of houseplants. They also feed on decaying plant material and love over-watered plants.
Finally, drain flies love moist areas and often congregate around standing or stagnant water. They’re commonly found near drains, gutters, basements, sinks, and even toilets that you don’t use often.
How To Fix It
Water, or wet areas, will not always draw gnats. Instead, it’s moist areas where organic or decaying material can be found.
Some of the most common areas include:
- Drip pans
- Sewage pipes
- Fruit bowls
- House plants
You can reduce the possibility of a gnat infestation by following the tips below:
- Flush toilets that are not used frequently once or twice a week
- Clean all the drains in your home regularly
- Change garbage bags every other day
- Wash out garbage cans when you change them
- Empty and clean drip pans regularly
- Inspect A/C units to ensure they’re not collecting water
- Store and cover food properly
- Keep basements and laundry rooms as dry as possible
- Dump mop buckets after use
- Put covers in sink drains that are not used often
- Do not over-water house plants
- Treat or re-pot infested house plants
Gnats Are Attracted to Certain Scents
In addition to moisture, gnats are attracted to certain scents. It’s how they find food and areas to breed and lay their eggs. But what scents are gnats attracted to?
Each type of gnat is drawn to something different, so if you have an infestation, the best way to determine what smells they’re attracted to is to look at what they’re hovering around.
Most gnats are attracted to fruity or floral scents (there’s also specific scents that gnats hate.) This is especially true with fruit flies, which are often found hovering around fruits and vegetables.
Additionally, the smell of fermentation will often draw many species of gnat. Drains, and even fermenting fruit could attract them to your home.
Some species are attracted to a more earthy set of smells. For example, drain flies are often attracted to sewage, and fungus gnats love the smell of decaying plant material.
How To Fix It
Although it might be impossible to remove every gnat-attracting scent from your home, there are ways that you can reduce the chance of a gnat infestation.
Make sure you keep fruits and vegetables appropriately stored and throw them away when they start to spoil. You should also keep an eye on stored potatoes as sometimes the ones on the bottom can rot faster than the ones on the top.
In addition to storing your food correctly, make sure to clean your drains regularly. Keep sink traps clear of food and use a garbage disposal cleaner like this Lemon Scented Drain and Disposal Cleaner to keep gnats from breeding in your sink.
Garbage cans are another common hot spot for gnat activity. Luckily, changing the garbage frequently will help reduce gnat activity. Also, placing deodorizers in the bottom of trash cans can help. You can read more about how to keep flies (including gnats) away from your garbage here!
Gnats Are Attracted to Organic Material
Finally, like most flies, gnats are attracted to decaying organic material. More specifically, moist decaying organic material.
Gnats are attracted to areas of the house where decaying organic material can be found, such as drains, garbage cans, compost piles, and sewers.
In addition to kitchen drains, some gnats can be found living in bathroom and laundry room drains. Even though these drains don’t harbor food, they do harbor quite a bit of gunk.
Some gnat species are attracted to sewage. These flies are often found hovering above sump pumps, septic systems, and sewage lines. Also, some gnats, such as the phorid fly, are attracted to pet waste.
How To Fix It
Removing or cleaning the areas in your home where decaying material is most often found is the best way to eliminate gnat activity.
Although composting is great for the environment and your garden, it can draw a variety of pests. So how do you get gnats out of your compost bin?
If you have a compost pile or bin, keep it as far away from your home as possible.
Keep the bathroom drains in your home clean by snaking them occasionally and using a deodorizing drain cleaner. You can also find drain brushes that scrub organic material off the walls inside the drain.
Finally, if you have house plants, make sure you don’t over-water them. Check them every other day and remove any leaves or stems that have fallen into the dirt.
You can also use coffee grounds in your compost to help keep gnats away!
What Is a Gnat Anyway?
Scientifically, the term “gnat” is commonly used to refer to any tiny, non-biting fly belonging to the sub-order Nematocera.
Over the years, however, this word has taken on a life of its own. People now use it to describe a variety of small flies (biting or non-biting) that hover or swarm around an object.
Unfortunately, there aren’t many collectively agreed-upon definitions of the word. For example, while most people agree that mosquitoes are not gnats, some scientists use the term to refer to both mosquitoes and blackflies.
Additionally, fruit flies are commonly referred to as gnats by the general public but not by a large majority of the scientific community.
Since our purpose is to help you learn what attracts gnats to your home and how you can get rid of them, we’ll try to include any small fly that you might consider a gnat.
Luckily, no matter what type of gnat you are dealing with, there are some things you could do when you find them in your house!
Most Common Types Of Gnats You’ll Find Inside
People refer to several fly species as gnats, and each is attracted to something different. It’s essential to identify which species of gnat you’re dealing with if you want to find out what’s attracting them to your home. Some of the most common house-dwelling gnats are listed below.
Regardless of what you are specifically dealing with however, it is always important to keep in mind that there are some main things that attract gnats into your home, and getting rid of them can help with you problems!
Technically, fruit flies aren’t gnats—they belong to a different sub-order. But since they’re often misidentified as gnats, we’ve included them in the list.
Fruit flies are small, non-biting flies that grow to one-eighth of an inch in length. They’re commonly brown, tan, yellow, or black and have reddish-colored eyes.
Fruit flies are attracted to ripe or over-ripened fruits and vegetables. You can also find them hovering around trash cans, sinks, mop buckets, plates of food, and fruit bowls.
Fruit fly traps like this Ready-to-Use Indoor Fruit Fly Trap can help eliminate these pests from your home. Additionally, you can eliminate fruit flies by keeping the areas they congregate clear of food or other organic material.
The best way to eliminate fruit flies naturally from your home is to:
- Keep sinks clear of dirty dishes
- Keep drain traps clear of food
- Keep garbage disposals covered
- Keep trash can covered and change the bag often
- Keep food covered and stored appropriately
- Keep sugary drinks covered
According to a study published in the Journal of Visualized Experiments, the average lifespan of a fruit fly is between 40 and 80 days. So as long as you follow the tips above, the flies should disappear from your home within a month or two.
Fungus gnats look similar to mosquitoes, but they’re much smaller. In fact, most adult fungus gnats only grow to one-eighth of an inch in length. They’re commonly blackish-gray in color and have light or clear-colored wings.
When present in the home, fungus gnats are often seen around house plants and congregating in windows. They’re attracted to moisture, decaying organic material, sunlight, yellow and orange coloring, and some perfumes and colognes.
According to a fact sheet created by Colorado State University, fungus gnats feed on fungi, algae, plant roots, and decaying plant matter. This is why they’re often seen hovering around house plants.
These tiny flies will often hitch a ride into your home on plants. Before buying potted plants from a store or garden center, check the plants for signs of gnat activity. These signs include yellowing leaves, mold growing on the dirt, root rot, and visible eggs.
Although the eggs might be hard to see (and some are almost impossible to see with the naked eye), most species lay small white or yellowish eggs on the surface of the soil.
You can also look for small, translucent worms. The small, thread-like worms are hard to spot, but if you see them, it’s a sure sign that the plant will need to be treated.
The easiest way to remove fungus gnats from your home is to re-pot infested plants and adjust your watering habits. Over-watering can cause mold and root rot, which will attract gnats. Additionally, adult gnats need a moist place to lay their eggs.
Another great way to remove fungus gnats is to add a soil cover to your potted plants. For example, covering your soil with decorative stones can keep gnats from accessing the dirt and your plant’s roots.
If you want to try this yourself, these Decorative Ornamental River Rocks look beautiful and they’ll help keep pesky fungus gnats away from your beloved plants!
You can also view our specific guide on what to do if you find gnats in your home!
Drain Flies (Moth Flies)
Drain flies (also known as moth flies and sewage gnats) have a moth-like appearance, but they’re much smaller than your average moth. In fact, adult flies only grow from one-fourth of an inch to one-eighth of an inch in length.
Drain flies are attracted to moisture, organic material, and sewers. You’ll often see them around areas that collect standing water or sewage.
According to a fact sheet created by AgriLIFE, adult drain flies feed on decaying organic material. Their larvae feed on algae, bacteria, and fungi found in slime that collects around drains and standing water.
Luckily, drain flies aren’t great at flying, so they usually stay close to their breeding site. This makes it easy to locate where the flies are coming from.
If you’ve seen drain flies in your home but aren’t sure where they’re coming from, try placing tape or a cup smeared with vaseline above nearby drains. Check the tape or cup every few hours. You’ll know the drain is a potential breeding site if you’re trapping flies in that area.
If you know where the flies are emerging from, take appropriate action. Dump any standing water and clean the area thoroughly. If they’re emerging from drains, use a specialized drain cleaner such as InVade Bio Drain Gel.
If you’re unsure where the flies are coming from, look for possible breeding sites near where you are seeing the flies. This could include drip trays under refrigerators or leaky pipes, areas around an A/C unit, or even the bottom of a bathroom trash can.
In addition to being a nuisance, sewage gnats can help alert homeowners to a problem. For example, they’ll often pop up when a leak is present under the floorboards of your home. For this reason, they shouldn’t be ignored.
Whether or not a phorid fly is technically considered a gnat is open to interpretation. However, we’ve included them because they’re often mistaken for drain flies or fruit flies.
Unlike drain flies, who are just a nuisance most of the time, phorid flies can pose a health risk because they inhabit some seriously unsanitary places. Unfortunately, they’re also one of the more complicated flies to get rid of.
Like many gnats on this list, phorid flies grow to around one-eighth of an inch in size. Although they’re often misidentified as fruit flies or fungus gnats, they’re identifiable by the distinct hump behind their head.
Phorid flies are attracted to moist, decomposing organic material. This can include various things, such as sewage pipes, drains, pet waste, dead animals, garbage cans, compost bins, and even dirty mops.
Although they can become a nuisance anywhere, people who keep animals might be more susceptible to an infestation.
The key to managing these yucky flies is to remove things from your home that might attract them. However, you’ll have to hunt down the breeding site if you already have an infestation.
Once located, remove any material the larvae are feeding on and clean the area thoroughly. If you cannot find the breeding area on your own, check out our local pest professional finding tool!
So, this is another gray area when it comes to gnats. Technically, the name midge refers to any small, mosquito-like fly. However, there are biting and non-biting midges, and this is where things get a bit complicated.
Most species of biting midges are flies that belong to the Ceratopogonidae family. Non-biting midges, however, often belong to the Nematocera sub-order. Oh, and there are quite a few species of each!
Since non-biting midges are often referred to as gnats, we thought it was best to include them. However, since there are around 1,100 species in North America alone, we’ve decided to include them as a broad, sweeping category instead of listing each species.
Midges often spend the first stages of their life in water. As adults, they emerge from the water and typically stay nearby (since they need to lay their eggs in water). This is why midges are often found near bodies of water.
If you’ve ever seen a cloud of dancing gnats, these are likely male midges. Although it’s not exactly known why they do this, males often congregate in large swarms that remain in one place. It’s hypothesized that this could be a type of mating ritual, or it might be a bunch of guys who found a good place to hang out!
While non-biting midges are not as annoying as biting midges, they can be a nuisance. Since they’re attracted to bright lights, you can reduce activity around your home by installing yellow lights like this Amber Yellow LED Bug Light.
Eye gnats are one of the most annoying gnats on this list. They’re small black flies with yellowish legs and grow to about one-eighth of an inch in length.
Although eye gnats do not bite humans or pets, the females feed on fluids and mucus secreted from the eyes, noses, and wounds of humans and animals. And they’re incredibly persistent.
According to the Journal of Economic Entomology, eye gnats lay their eggs in moist soil containing large quantities of decaying organic material. Since farms often till plants into their soil, crop fields are a primary breeding site for eye gnats.
Unfortunately, because they’re so small, these tiny flies can be carried by the wind to nearby schools and towns, where they become a massive nuisance.
Insect repellents containing DEET and homemade eye gnat traps (containing raw eggs) can be effective against the flies for short periods. Additionally, local pest control agencies can spray around your home and yard to help eliminate these annoying pests.
That’s A Wrap!
Love them or hate them, gnats do have an important role in the ecosystem. They’re a great food source for many species of birds and bats; some species eat pest insects; and they play a role in the pollination of a variety of plants.
But, while they might be important outside insects, nobody wants to find them inside. Luckily, by keeping your home free of moisture, decaying organic matter, and certain scents, you can make sure these helpful pests remain outdoors.
If you’d like to learn more, take a look at our full guide on the reasons why gnats are in your home!
Cranshaw, W. S., & Cloyd, R. A. (2009). Fungus gnats as houseplant and indoor pests. Insect series. Home & garden; no. 5.584.
Linford, N. J., Bilgir, C., Ro, J., & Pletcher, S. D. (2013). Measurement of lifespan in Drosophila melanogaster. JoVE (Journal of Visualized Experiments), (71), e50068.
Mulla, M. S. (1963). An ecological basis for the suppression of Hippelates eye gnats. Journal of Economic Entomology, 56(6), 768-770.
Sansone, C., & Minzenmayer, R. (2003). Drain Flies (Moth Flies or Filter Flies). Texas FARMER Collection.
Zack is a Nature & Wildlife specialist based in Upstate, NY, and is the founder of his Tree Journey and Pest Pointers brands. He has a vast experience with nature while living and growing up on 50+ acres of fields, woodlands, and a freshwater bass pond. Zack has encountered many pest situations over the years and has spent his time maintaining and planting over 35 species of trees since his youth with his family on their property.
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