What do drain flies look like?

Quick Answer:

Drain flies are frequently called "moth" flies due to their resemblance to moths. These tiny flies have bodies coated in tiny hairs, giving them a furry look. Their colors range from light tan or gray to black.

Drain flies (family Gerridae) are small flies that can be found in most homes, restaurants, and buildings. They are commonly known as drain flies because they like to feed on decaying organic matter, or ‘drain.’

Drain flies have a large range of nymphs. Adult drain flies have wings that are transparent and hairless. When they are young, drain flies may look like moths with their characteristic pointed foreclaws and moth-like antennae. They grow larger as they mature. Adult flies have a wingspan of up to 5 millimeters (mm).

These tiny flying insects are common in hot, humid places like kitchens and bathrooms where organic material is plentiful and food sources are abundant. Their presence doesn’t necessarily mean that something is wrong with your home; it could simply be because there’s plenty of suitable food available for them to feed on.

Moth Flies

Drain flies are also known as “moth” flies because of their resemblance to moths. They are small and furry with large, ovoid wings and prominent antennae.

They can also go by many names. Some people call them moth flies, sewer flies, filter flies, and even fruit flies. However, they are much different than fruit flies. Though they can look similar, drain flies hang out around your drain and look a bit more like moths rather than flies. 

When at rest, the moth flies folds its wings over the body in a characteristic roof-like manner. 

They are 2 to 5 millimeters long depending on the species. They are weak fliers and are often seen walking near breeding sites. Females lay 30 to 100 eggs in masses on the surface of the breeding medium.

How do you get drain flies?

Drain flies are found in homes and restaurants, so they can be easily controlled. Using sticky traps is one way to get rid of them. Simply place a trap near where the flies are most active, such as drains in your sink or bathtub. Another way to get rid of them is by vacuuming or mopping up their waste before it starts to smell bad.

It’s important to note that prevention is key if you don’t want these tiny flying insects crawling around your home. If you’re facing an infestation, you’ll need to take preventative measures like using insecticides, getting rid of water sources where they live, or installing screens over drains and other openings where they might enter your home.

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Drain fly larvae

Drain fly larvae are not longer than 4 to 10 mm when fully mature and they are slender with a dark strip on the “back” or dorsal area. Larvae do not have eyes, and they are legless. On one end of the larva, there is a dark breathing tube used to extend out of the film to obtain air.

Drain fly larvae feed on the drained sludge and can survive in high temperatures with low oxygen conditions. . When food sources become scarce, they may become cannibalistic

Drain fly eggs

Drain fly eggs are about a millimeter long and have a brownish-tan color. They look like tiny grains of rice.

The larvae of drain flies are called maggots and they are white with a gray head and two black spots near the head. They grow up to 2 cm (about an inch) long and they can be recognized by the small, pale brown or black, legless body segments that make them resemble worms.

Drain fly nymphs

Nymphs are the most common stage of a drain fly. Nymphs have wing covers that are usually brown, gray, or black and they can be confused with other insects such as mosquitos. They can also be mistaken for spiders because they have round bodies with little legs.

Drain fly adults

Adult drain flies have transparent wings with no markings. They also have hairless bodies and, when they are young, may resemble moths with their characteristic foreclaws and moth-like antennae.
Drain fly adults are gray to dark gray in color. They have a wing span of up to 5 mm.

How to get rid of drain flies?

If you find drain flies in your home, you can try traps or insecticides to get rid of them. For more information on what repellents and sprays, you can use, check out this article here.

Drain flies are not known to carry diseases or transmit any diseases. However, their presence can be a health concern for people with allergies.

If you have a small child in the home, it’s advised to use air-conditioning or fans to reduce the number of drain flies that enter your home. If there’s an abundance of food sources around the house, it may be best to close the doors and windows and be sure they’re closed tightly when letting children play outside.

The best control for these flies is to remove the breeding site, which is the organic material that is collected in the drain. The site must be located and cleaned.

If found in rotting vegetable matter, the source should be destroyed. Clean dirty garbage containers, wet lint under the washing machine, and even standing water in containers under houseplant pots.

Outside the home, inspect air conditioners, birdbaths, shallow, stagnant pools of water, and sewage treatment facilities upwind as adult flies travel with the wind.

If you can’t get rid of drain flies on your own, the most effective way to eliminate drain flies from your home is to contact a professional pest control expert at the first sign of their presence

Traps and remedies for drain fly infestation

Various traps and remedies to get rid of drain flies are also available if you find drain flies in your home or business. Some people use a “drain fly paper” to attract and trap the flies. Paper is placed under sinks near the drains. This starts a chemical reaction that attracts the drain flies.

Another remedy for sucking up these annoying pests is using sticky tape on a floor near sink drains; try using Play-Doh or kitty litter as an adhesive. Drain flies are attracted to the particles and can’t escape.


Drain flies are a type of fly that can become a nuisance when they make their way into your home, particularly your plumbing system. They’ve been known to lay eggs in the plumbing, which can cause clogs and allow other bugs to get in.

The best way to prevent them is by having regular inspections and cleaning. If you don’t want to do this yourself, you can hire a professional, or you can buy a DIY drain fly trap.
You might also want to try some organic pest control products that can be used to control these flies.


What are the different stages of drain flies?

The different stages of drain flies are egg, larva or nymph, pupa, and adult.

Egg: These eggs are buried in soil or decaying organic matter. They hatch within 7 to 10 days.
Larva: Larvae are very thin and threadlike. They have three pairs of legs and two pairs of antennae.

Nymph: Nymphs have six legs and have a scaly surface without hair.

Pupa: Pupae are normally dark brown, cylindrical tubes up to 1/4 inch (6 millimeters) in length. After approximately two weeks the pupae become adult flies. The life cycle for drain flies takes about two weeks from egg to adult.

What do drain flies eat?

The small size of drain flies allows them to get into very small spaces where other species cannot go.

Drain flies can be found in most homes in areas where there is food or decaying organic matter such as trash bins or bread crusts. They usually prefer dark places such as closets and pipes but can also be found in other visible places such as windowsills or under shelves in pantries or cupboards.

They prefer warm and humid places and are most active during the day. Their life cycle is very short – just a few days – so they need to find a fast source of food to survive. They do not lay eggs, instead, the life cycle is complete after the adult fly has emerged from the pupa.

How do drain flies fly?

In humid environments, drain flies can thrive, but they can also cause problems because they will start to breed rapidly and consume all the available food. When this happens, there won’t be enough for the other organisms in the area. This could lead to disease or death for some of the other organisms in the area.

Adult drain flies can only fly for a few minutes before they must get back into their nymph stage to continue feeding on the organic matter around them.

They will crawl into drains and wet walls or floors and hide until nightfall when they emerge to consume whatever food is available before returning underground at sunset to rest until the following day.

They emerge again to eat more food until sunset when they crawl back into tiny holes or cracks in drains or wet walls where they will rest until daylight.

Then, they emerge again to feed until sunset when they return back underground again until daytime when they crawl out and fly around consuming more organic matter before returning underground every evening.

This cycle continues throughout their life cycle as long as organic matter is available for them to eat.

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