It’s a moth, it’s a dust bunny, it’s… a fly? Drain flies may look similar to moths, but these little pests are relatives of the equally annoying fruit fly and horse fly.
While there are thousands of species, one species in particular is notorious for invading homes, so we’ll focus mainly on that one (although these tips will work on just about any species).
Let’s look at what you can do to eliminate the little drain invaders as well as how to prevent them from coming back. Then we’ll get down and dirty, getting to know drain flies and what makes them buzz.
See Also: Getting Rid of Cluster Flies
Getting Rid of Drain Flies
Dealing with a drain fly infestation is both easy and complicated. This is because of the way these pests have developed a resistance to extermination methods that are commonly used while still being vulnerable to some very simple household techniques.
Methods That DON’T Work
Before we discuss some easy kill methods, let’s take a moment to look at what simply doesn’t work.
Due to their preference for heat and humidity (and habit of using your tub or kitchen sink as a breeding ground), they have a high thermal tolerance. Hot water, even if boiling, won’t have any effect on drain fly eggs or larvae.
Chemical drain cleaners like Drano also have notoriously little to no effect on these critters. The hairs on both adult drain flies and larvae makes them highly water-resistant. It also means that common chemicals such as Comet or bleach will have little or no effect.
Methods That DO Work
Now that we’ve eliminated the ineffectual, what about effective solutions? You might be using some of these already, and all are quite effective for both elimination and prevention if used regularly.
1. Mechanical Cleaning
Few things beat a long metal pipe brush. Remove the cover and get to scrubbing. You can use some Comet cleanser or simple baking soda if you want to avoid harsh chemicals.
While this method takes a bit of elbow grease, the results are undeniable and you will likely eliminate some eggs and larvae in the process. But for complete elimination, you may need to combine with another method.
2. Enzyme Cleaners
One of the most effective ways to deal with drain flies is using an enzyme cleaner. These products contain beneficial bacteria that break down the organic matter drain flies feed on, effectively starving them out.
Regular liquid enzyme cleaners like the popular Green Gobbler will work to some extent but a gel-based formula, like Bio Drain, is the best way to go. The thick consistency allows it to stay in contact with the problem areas longer than liquid cleaners.
For optimal results, apply it at night so it can sit in the drain undisturbed. Simply apply the gel around the inside of the drain, allowing it to coat the sides as it slowly works its way down. If the gel seems too thick to go down, avoid the temptation to dilute it and simply let gravity do its job.
Regular use of enzyme cleaners not only eliminates drain flies but also helps prevent future infestations by keeping drains clean and inhospitable to these pests.
3. Volcano Cleaning
Chances are you’ve built a model volcano at some point in your life using vinegar, baking soda (and perhaps food dye to make the lava red). This combo of acid and alkaline just so happens to also be one of the best home cleaning methods out there. You just need one cup baking soda and one cup of vinegar (preferably white vinegar).
Dump the baking soda down your drain, then carefully pour the vinegar in afterwards. Let it sit for about 15 minutes and flush with hot water. The foaming chemical reaction loosens hair and other buildup, allowing you to flush them away. This not only helps to eliminate the flies’ food, it kills odors and bacteria as well.
4. Vinegar Traps
Those same homemade bottle traps used for fruit flies can work on adult drain flies. Just use some apple cider vinegar as your bait. Be warned, you’ll still have to deal with any larvae separately.
5. Call a Professional
For persistent problems, professional pest control companies are an effective (and usually affordable) last resort.
Preventing Drain Flies
This is one of those insects that you shouldn’t try to completely eradicate. However, they’re also one that should remain out of sight and out of mind. Here are a few simple tricks to ensure these little annoyances don’t make an appearance.
Checking for Drain Flies
Spotting a random drain fly isn’t necessarily a bad thing, as they help clean the waste from your drains. However, spotting several is a sign that your pipes need a serious cleaning. The good news is that you can easily test for an insect problem without having to constantly monitor your kitchen and bathroom.
Simply cover part of the target drain with tape and let it sit for a while. You can also use a clear plastic cup or even a small plastic bag. Check these traps occasionally to see if any adult flies have emerged and gotten confused. This can be a clear indicator that you have a pipe problem in the making.
Clean Regularly
It should go without saying that the best way to prevent a critter that feeds on decaying organic matter is to eliminate any decaying organic matter.
Clean your sink, tub, and toilet regularly. You don’t need fancy chemicals, as even vinegar and baking soda can work wonders for flushing out scum. Be sure to also remove the drain covers and give the opening a good cleaning as well.
If your kitchen has a garbage disposal or dishwasher, make sure these are cleaned out often. The same goes for your oven, microwave, and other places where food might splatter or spill.
Flush Those Pipes!
Be sure to run water through all of your pipes periodically, especially in the basement or other infrequently used plumbing locations. This will help ensure the water doesn’t have time to stagnate and scum over.
You can also use plugs to help discourage the flies from entering your pipes when you’re not using them. Remember to also target any floor drains or outdoor storm drains while you’re at it!
Remove Sources of Standing Water or Food
Finally, remove any standing water on your property. These can invite a whole host of unwanted pests. Fill in places that tend to puddle over when it rains.
Make sure any mop buckets and similar cleaning receptacles are thoroughly dried when not in use. Keep trash bins covered and dispose of food waste promptly. And if you compost, be sure the pile is far from your house and properly contained.
Getting to Know Drain Flies
Drain flies come from the family Psychodidae. There are more than 2,600 known species, although the one you’re most likely to encounter in your home is Clogmia albipunctata. These little pests are known by a number of nicknames, including bathroom moths, filter flies, sewer flies, sewer gnats, and sink flies.
Identifying Drain Flies
Adults are fairly distinct, with rounded wings, brownish-grey, grey, and black hair on the body and wings, and feathery antennae. Clogmia albipunctata is also distinguished by tiny white spotting on its body and wings. This gives them the appearance of small moths measuring as tiny as .08 to .10 inches long.
The larvae (often called drain worms) are twice as long with transparent, flattened bodies and a black head. While able to swim, the larvae of many species are able to anchor themselves to drain walls. However, they cannot breathe underwater and must use their snorkel-like spiracle to breathe.
One easy way to tell a drain fly from a moth is the way they lay their wings out in a heart-shape. Moths will either lay their wings flat like butterflies or fold them along their bodies.
Another easy way to tell them apart is the lazy, almost clumsy way in which drain flies fly. They much prefer walking or running to flying when the choice arises.
Life Cycle
These insects have a relatively short life cycle. Adult females will lay one batch of 30 to 100 eggs above the water line in drain pipes. The eggs hatch in 48 hours, with the larval stage lasting roughly 18 days over four instars.
The pupal stage takes five days, with the emergent adults lasting only around 12 days, with other species living as long as 20.
What Do Drain Flies Eat?
An adult diet consists primarily of nectar and water. Meanwhile the aquatic larvae feast upon decaying matter.
Why Are There Drain Flies in My House?
These insects are attracted to warm, humid places, and dirty drains are ideal. Not only do the drains provide humidity and shelter, the accumulated sludge is a perfect food source. Thus, spotting an adult sneaking out of your sink or tub drain is a good indicator that your pipes are lines with waste or debris.
They’re also known to come up the pipelines from septic tanks, sewers, and to breed in sources of stagnant water.
Are Drain Flies Dangerous or Beneficial?
For the most part, the only dangers posed by drain flies are to your sanity and a small risk of myiasis (parasitic infection of larvae under the skin). However, this is almost unheard of outside of cases with very poor hygiene.
While they can also carry bacteria, they’re not known to transmit pathogens to humans. Asthma and allergies may be triggered by inhaling bits of fly corpses.
Meanwhile, the larvae are a crucial part of Nature’s waste disposal unit. Their purpose is to actively eat away at scum and hair caught in your drains. Not only does this help prevent clogs, it can also reduce the risk of illness.
The adults are also helpful with pollination, although not nearly as effective as bees and wasps.
Morgan is a certified entomologist and pest control consultant and a member of the National Pest Management Association.
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A neighbor’s cat gave me her fleas about 6 months ago, I did not hire an exterminator, and didn’t start acting against them until a couple of months ago. Vacuuming (hard floor only–laminate) regularly helps, crevices especially, and PT Alpine bed bug and flea killer helped a lot. But they have made themselves at home, especially my groin, and face and ears. Soapy water–Lever Soap–is my only weapon on my body. Is that effective? Should something else be used. The hair on my scalp has been cut off, so that fleas can’t make a home there. Neither veterinarians or dermatologists, or primary care doctors are helpful.