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Drain Fly Facts

  • 1.5 to 5 mm in length.
  • Considered to be part of the gnat family.

Drain Flies

Also known as moth flies, drain flies are quite common, and although they’re basically harmless, they can become very irritating. Most homeowners find drain flies in a bathroom or kitchen. The term drain fly was coined because of the fact that these insects lay their eggs inside of the slime that develops in sink drains. Although many people consider boiling water and bleach to be effective remedies, it’s a better idea to attack the actual slime that develops inside of the drain.

What Are Drain Flies?

Drain flies are small and have light-colored wings, and they’re considered to be part of the gnat family. The wings of a drain fly have many scales, so when killed, drain flies produce a small dust cloud. It’s common to find drain flies resting on ceilings and walls, and if bothered, these gnats will hop and make short flights to new resting locations.

In many situations, drain flies cause a temporary problem. Since these flies are known to breed in standing water, it’s common for homeowners to find a drain fly infestation after coming home from a vacation. Drain flies don’t breed in moving water, so regular household activity helps to keep them away. A typical drain fly can be 1.5 up to 5 mm in length.

Drain Fly Infestation

A drain fly infestation will become noticeable when a significant number of adult drain flies are present. In most cases, drain flies can be found resting on bathroom walls or near breeding locations. A drain fly infestation can easily become troublesome when the population becomes excessive.

Most drain fly infestations occur in moist areas and near organic materials. As the name would imply, drain flies are normally found in storm or home drains. However, compost piles and decaying logs are two other locations that make great breeding grounds for drain flies. Although homeowners can take action and try to remove a drain fly infestation, it might be a better idea to seek professional help.

How to Get Rid of Drain Flies

Many homeowners want to get rid of drain flies. The best way for homeowners to accomplish this goal is to eliminate breeding sites. It’s essential to clean household drains, which includes removing organic slime that has accumulated in the drains. By pouring a pan of boiling water down household drains, homeowners can achieve short-term extermination.

However, the larvae of drain flies can be hard to drown, which is due to the fact that the larvae can trap air bubbles. It’s important for homeowners to avoid pouring insecticides down household drains. The average life cycle of a drain fly is 10 to 15 days.

Drain Fly Health Concerns

It’s true that drain flies do not bite humans, but in large numbers, drain flies can become quite the nuisance. Since drain flies do not bite or transmit diseases, they don’t pose any health concerns. To properly remove drain flies, homeowners should contact a professional pest control expert.


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