What are Drain Flies?

drain fly

If you notice some fly-like black or dark brown insects at home that are an eighth of an inch big, they are most likely drain flies. You can verify it easily because they have a specific pattern of veins visible on their wings.

People also call these unwanted guests as sewer flies or moth flies. Another difference between flies and drain flies is that their body is completely covered with hairs. At first sight, people often confuse them with fruit flies or phorid flies.

Where Can You Find Drain Flies?

Getting rid of drain flies also means that you are going to have to find and get rid of drain in your house. The key thing to understand about these insects is that a drain is the most ideal place for them to breed. Therefore, identifying and fixing the drain is part of the pest control process.

The good news is that there are plenty of drain cleaner products that can instantly destroy the area where flies drain from. The obvious thing to start with is to look for standing water inside and around the house.

For example, standing water can commonly form in the bathroom and around garbage containers. But sometimes a moisty area is more than enough for drain flies to breed. If there is a spot around the house that is constantly wet such as under your plants or air conditioner, you should definitely check that.

Although these insects live for only two weeks, it is important to get rid of drain flies because they can reproduce rather quickly. In fact, their entire lifecycle is about 30 days if you include the    larvae stage. They cannot cause harm to us humans directly. They only do it indirectly by transmitting various types of bacteria.

By looking for water seepages, leakages, bathroom walls and under slab areas with organic matter, you have a high chance of revealing breeding spots.

Easy Ways to Get Rid of Drain Flies

It usually doesn’t take much time to get rid of drain files and there are some highly effective methods as well. The easiest one is to use some cleaning products that you can find at home and scrub the drain area thoroughly with a brush. Then, just pour boiling water into it.

Repeat the process at least once a week and it will keep the drain flies away. The other popular method is to mix together a cup of vinegar and another cup with 50% salt and 50% baking soda. Then, pour the solution down the drain and let it do the work.

After a few hours, you can pour some boiling water into it and it is done. This is sort of a DIY method but there are numerous drain cleaner products available as well. You don’t necessarily have to buy cleaning products that are specifically made against drain flies.

The point is to get rid of the debris and organic matter that can build up over time so that the particular spot doesn’t turn into a breeding ground. 

Keeping Things Clean is the Best Pest Control

We can conclude that in fact all you need to do is to keep the drain clean. Usually, it is enough to perform thorough drain cleaning once a week. This basically makes it impossible for drain flies to breed and hatch eggs.

This applies to all the other spots in your house where moisty spots can potentially develop.

28 Questions and Answers about Drain Flies

What Does a Drain Fly Look Like?

A drain fly does not differ much in size compared to other common types of flies. Most of them is about a 1/6 of an inch in length and their body is completely covered with hairs.

How Long do Drain Flies Live?

It takes about a full month for the drain fly to go through its entire life cycle. It spends 8-24 days in the larval stage, then goes through the pupal stage and then lives about two weeks as adults.

What are Drain Worms?

Drain worms are tiny, black worms in toilet, shower or under the wasching machine. Because adult drain flies lay 10-200 eggs, you will probably see plenty of them.

What is the Difference Between a Fruit Fly and a Drain Fly?

There are significant differencies between drain flies and fruit flies. Drain flies are about a 1/6 of an inch in length, their body is completely covered with hairs. They have a pair of antennae that helps them navigate while flying and moving around. You are not really going to see them flying though, as they rather prefer to walk. Fruit flies have either black or red eyes. The rest of their body is pretty much evenly colored except their abdomen, which has dark stripes. While the red-eyed ones are of the same size as drain flies, the black-eyed ones are slightly bigger. Compared to house flies, they are really not as big. They buzz around in the kitchen looking for fermenting leftovers.

Can drain flies lay eggs in Human?

Drain flies do not lay eggs on human body. They lay their eggs into a gelatinous film that forms on the fermenting organic material. Getting rid of drain fly eggs is very simple.

What are the little black worms in my house?

The little black worms can be drain worms. They are about 1.5 to 5 millimeters and do not have legs or eyes.

Why drain flies keep coming back?

If drain flies keep coming back, there is a possibility that there is another infestation site. Other pumps, drains, and sinks should be thoroughly checked to discover secondary infestation and handle it too.

What can I use to kill drain flies?

Drain flies can be killed by using house remedies and commercial products as well. You can pour hot water into drain, use bleach or well-known products like Drano. The Invade BioDrain is a 100% bio solution to get rid off drain flies. Here we collected more than a dozen ways to kill drain flies.

Can drain flies bite?

No, drain flies can’t bite. They are living in drain pipes where eat organic materials like hair, body hair and skin pieces. Their larvae are disgusting and the small, flying flies are very annoying as well. If the number of drain flies become too high in drain pipes, these small animals can cause blocks.

Are drain flies harmful to humans?

In general, drain flies are not harmful to humans. But these small flying flies live in drains so they can carry bacteria as well. And if you consider the fact that drain flies can touch your food, we can say that drain flies might be harmful to humans.

Where do drain flies live?

Drain flies live in drains and everywhere they can find safe place for breeding. You can find their larvae near the shower, toiler or washing machine – literally everywhere where there is enough water to live in. In some cases, drain flies can be found in air vent system, basement or septic tank as well.

Are drain flies common?

Yes, drain flies are very common. You can meet them almost on every continents, from Europe to Australia, from Asia to America. Most of US citizens at least heard of drain flies, but it is also very common that you find these small flying flies or their black worms near the toilet or shower.

Do drain flies smell?

Drain flies use decomposing organic debris within pipes as their breeding sites; they are also fond of standing water, decomposing food wastes, and plumbing leaks. As a result, a multitude of drain flies would give off a foul, vomit-like smell — not surprisingly, given where they breed. The unpleasant smell is particularly likely to occur during the summer, and a significant number of flies — about a thousand — should be present for it to appear in the first place. Even though the odor itself is harmless, the dust carried by drain flies is known to worsen the manifestations of bronchial asthma.

Are drain fly larvae harmful to humans?

In small numbers, these drain fly larvae can be even useful, as they decompose the organic material in pipes and prevent them from clogging. But, when ingested, they may cause myiasis — a parasitic disease in which the larvae develop inside the human body and feed on it. There is always a possibility that a worm or two will get into your nose or mouth. For this reason, drain fly larvae can be harmful to humans.

What do drain fly larvae look like?

Drain fly larvae look like transparent worms with a dark head, commonly around 4-5 mm in length. In most cases, larvae remain unseen, as they feed on organic film deep within the pipes. Sometimes they can be spotted at the moist edges of infested drain openings, especially those in showers.

Can drain flies lay eggs in humans?

Drain flies are part of the Psychodidae family — they are not capable of creating an infestation on unbroken skin. Still, drain fly eggs or larvae can get into the human body with food and water. It will then lead to accidental myiasis: the larvae grows and develops inside the human body, even though they do not need a host. Maggots are most likely to infest the digestive tract, but the brain and even heart may also be considered as possible infestation sites. The chances of such a scenario are very low, but it is still a good idea to keep food and drinks in a place that cannot be accessed by the flies. A tiny drop of water is enough for them to lay eggs, and you better not somehow drink that drop afterward.

Do drain flies spread diseases?

Drain flies are associated with filth and unsanitary conditions, and there is a good reason for that: they dwell in places full of decaying goo, bacteria, and fungi. And while it would never hurt to take precautionary measures, there are no known records of diseases transmitted by drain flies. They can carry bacteria with them though, so exterminating these pests is essential for kitchen and bathroom sanitation.

Do drain flies sting?

Luckily, drain flies do not sting or bite. As a result, they can not pierce through the skin and deliver harmful microbes directly into the bloodstream.

How to stop drain fly infestation?

Drain flies have to be exterminated as fast as possible due to their breeding speed. If the issue is not solved at the early stage, it gets worse and becomes more severe, including additional infestation sites, hundreds of flies across the rooms, and exposure to accidental myiasis. The infestation can be stopped by using home remedies, natural cleaners or commercial drain cleaner products. Here is our list of drain fly treatments.

Are drain flies seasonal?

Even though drain flies are sensitive to temperature changes, they persist inside the buildings and continue to breed even in winter. Outdoors they have a much harder time and usually die off. Once the weather warms up, drain flies grow in numbers and become problematic. So to call them seasonal would be a stretch, as they are a nuisance all year round without proper handling.

Will drain flies go away?

Given that they can survive winters indoors and continue their life cycles, we can say that drain flies will not go away by themselves. These pests can dwell deep within the pipes until conditions are suitable for them — and then cause an outbreak with many breeding sources in different drains across the house. It is advisable to avoid postponing and implement control measures at the earliest possible stage of infestation. We mentioned this topic deeper here: Drain flies keep coming back

Why do drain flies come out at night?

Drain flies live in generally dark places — pipes, crevices, drains. Therefore they do not get to benefit from daylight anyway. Insectivores, such as birds, can be evaded at night and the heat of the day is can be avoided.

Are drain flies attracted to light?

Yes, drain flies are attracted to light. It is noteworthy that technological advancement resulted in a significant disadvantage of the nocturnal lifestyle: our lights are so bright, and there are so many of them that drain flies get overwhelmed and go astray.

Are drain flies attracted to uv light?

Yes, drain flies are attracted to uv light as well. Drain fly light traps that lure insects and either kill or trap them were designed on that basis.

Can drain flies come from the toilet?

Drain flies lay eggs in standing water. If the toilet was not in use for a long time, the chances are a film of bacteria has formed on the water surface; this film can be used as a feeding source for moth fly worms. This type of infestation will fade away as soon as the toilet is used regularly once again. It is worse if an unspotted leak is present: drain flies can use a leaking spot as a breeding site until it is located and eliminated. Drain flies do not usually get into houses through toilet pipes. They make their way in through tiny holes, windows and basements.

What do drain flies hate?

Drain flies hate cleaning and pipe maintenance, that is for sure. To breed, they need your pipes to have a fair amount of residual organic goo inside — so a swipe or two with a flexible pipe dredger is a way to start. Follow this procedure by pouring boiling water down the drain, as it will additionally take care of some larvae. Some prefer to use a bleach solution or sometimes vinegar, but it may be harmful to plumbing. It is important to check your plumbing details to not harm any of the system parts.

What smells do drain flies hate?

Drain flies hate the smell of lavender, peppermint, lemongrass, eucalyptus and other kind of essential oils. Spray some of them around your shower and toilet and the flying flies will go away for a while. It is important to know that this is not enough to get rid of drain flies, house remedies or commercial products might be used to kill the larvae and eggs as well.

What is the life cycle of a drain fly?

Drain fly female is capable of laying up to 100 eggs at a time. Eggs hatch in approximately half a day, and thus the larvae emerge. Depending on species and conditions, the larvae pupate in the next 9 to 15 days. At last, after the pupation, they enter the stage of an adult fly. Adult flies live a little longer than 15 days. The entire drain fly life cycle usually takes from two to four weeks and depends on the environmental conditions. In suitable conditions, it can be reduced to as little as one week.

Will Drano kill drain flies?

Yes, Drano will kill drain flies and fruit flies as well, but the whole question is a bit more complicated. Using Drano for drain flies and drain worms is like using A-bomb for fishing, there might be too much side-effects. There are more eco-friendlier solutions against drain flies which we mentioned in this article: Will Drano Kill Drain Flies?