Drain Flies
Pest Control


What are Drain Flies?

As a part of the gnat family, drain flies can be identified as pests that have light colored wings covered with fine hair that makes them look like moths. You find them perched on walls, on the ceiling, on ledges both in and outside the home, and any place that does not have constant movement. If they are bothered with movement, they hop instead of fly away to find another rest stop. They breed in water pretty much like mosquitoes and can cause an infestation to manifest. Drain flies vary in length that ranges from about 1.5 to 5 mm and are creatures of habit where they tend to return to their territory, but if they sense any danger, they flit across to the next spot.

Habitat and Behaviour

An influx of adult drain flies causes an infestation, which can take root in a building or outdoors. Since drain flies are quite used to breeding in moist areas and near materials that are organic in nature, you may find them primarily in storm water drains, or even the drains in your home. However, they do find a place to nest on walls and compost piles and anything that is stagnant like decaying material where they breed faster than the speed of light.

Drain flies need adequate moisture to survive. They have a tendency to make their home where there is an accumulation of water. They breed both indoors and outside but prefer the latter during the hot season. They find areas of the home like air conditioning units, clogged gutters, toxic drains, moss-ridden tiles, as an ideal place to manifest. One can find wriggling larvae in stagnant water. This should be attended to immediately before there is an influx of the pests taking over the home and the surrounding area. Their food habit is decayed vegetation in both plants and animals and sediments.

Drain Fly Life Cycle

The drain fly goes through a complete metamorphosis once the eggs are laid, going on to the larva stage, the pupae stage and finally the adult stage. Larvae last from 8 – 15 days while pupating. During the gestation period of the female drain fly, groups of eggs are laid on any organic material to ensure that the young ones are not destroyed. When the eggs are laid, they usually hatch after two days where they proceed to the larva stage. Their bodies during the larval stage give them a head and a siphon that works as a breathing mechanism. One can say that the general life cycle of an adult fly takes about 24 days, which is dependent on the temperature of the place.

Problems/Damage due to Drain Flies

Unlike other insects, drain flies do not damage any structures, plants or anything for that matter. Since they manifest in areas that are prone to decay, like the sewer and drains, in manure, compost, and raw sewage, they are carriers of pathogens, which can cause an outbreak of deadly illnesses. In the home or in areas where a sterile environment is of prime importance, drain flies can cause harm as they spread allergens. If there is an infestation, the chance of the flies falling into food or their wings may become a constant resulting in health related problems.

Do Drain Flies Bite?

One can consider these flies to be a nuisance but when it comes to biting humans, they certainly do not bite. The problem is that when they form an infestation in the home, it is of prime importance to get rid of them before they sprout larva in stagnant water or in moist areas. The question of whether they bite is irrelevant because they do not, but they do cause havoc when they manifest.


Prevention is perhaps the best remedy to follow to control an outbreak of pests. However, simple ideas like pouring hot water down the drain along with caustic soda or regular soda work as a short-term extermination of sorts. Down the line, unfortunately, it may not work, as getting rid of larvae is not possible as they (larvae) invariably trap the air bubbles. The best way possible, if you are not looking for an exterminator (which is not the right choice really), is to use an enzymatic drain cleaner. This ensures that the larvae and adult drain flies are zapped away before taking over your drain and hopping over to your home. Once this is done, it is necessary to pour a large amount of water down the drain, so that any leftover larva gets flushed out effectively.

Chemical Sprays

Once the larvae are done away with, you need to deal with the adult flies. Chemical Sprays are an ideal way to remove these pests. Refrain from using them in the kitchen because they are toxic and you would not want a few drops to be exposed to edibles.

Liquid Dish Soap

Dish soap has borax in the ingredients, which is a pesticide of sorts. Add about 10 drops of the liquid soap and two cups of water and spray this on the drain flies. The spray will zap the flies away immediately.

Set a Trap

Remember drain flies are not rats. If you have an infestation, go all out with the treatment of setting a trap, which is ideal in the kitchen. In an open bowl, add equal quantities of white vinegar, water, and sugar with liquid dish soap. Leave it in the open for a couple of hours or overnight. This attracts the flies and they drown immediately.

Whack them with a Swatter

Anyone who comes into contact with a fly will automatically want to whack the insect. The problem is that they can leave a trail of blood behind on the walls. Use a mechanical swatter or a battery operated racquet swatter and zap them away into oblivion.

Call in a Professional

Most people prefer to try all the tricks in the book to eliminate any infestation of pests in the house. Unfortunately, not many of the ideas can reduce the infiltration of these winged monsters. The best method is to call in a reliable pest control agency that will eliminate any of these pests from taking over your home. In addition, not every method is foolproof, and if you have a serious problem with drain flies, the best method is to call in professionals who find the source and destroy them with aplomb.

Tips for prevention and control

The preeminent way to keep away drain flies from taking root in your home or commercial enterprise is to make sure that you refrain from leaving scraps around – they have a tendency to feed on rot and stagnant water. Here are a couple of tips that prevent drain flies from making your home their home.

  • Remove any wet organic material from open sites. If you have construction work going on, seek advice and help from a pest control expert. They will zap away the eggs, larvae and adult flies in an instant.
  • Drains must be cleaned regularly. If there are any corroded or broken pipes, repair them immediately. This will ensure that there is no sign of larval habitat.
  • Keep flies out of your home or office with the use of screens or windows that do not have any opening in the mesh or glass. Ensure that any torn or damaged mesh or glass is replaced immediately. Air vents also need to be enclosed with firm mesh as a preventive measure to stop pests from flitting along.
  • Light, as we all know, has a tendency to attract flies. Naturally, as it gets darker in the evening every room needs adequate lighting. The idea here is to make sure that the lights are strategically placed away from doors or open windows. This prevents insects from flying into your home. Insect lights or even sodium vapor lights work as deterrents.   

Aside from these simple ideas, here are workable methods to keep drain flies away.

  • Ensure that the drains are clean all the time without any sign of clogging with debris.
  • Do not collect stagnant water either inside the house or outside. Remove any sign of stagnation, which not only breeds drain flies but mosquitoes as well.
  • During the rainy season, ensure that any water has a proper drainage system in place even in the lawn.
  • An insect growth regulator must be sprayed into the drains at least once a week so that any sign of eggs or larvae are removed before an infestation occurs.

If the problem is severe, the foolproof method is to call in a professional pest control agency to address the issue from the get. 

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