Mold Flies

Since black mold often develops in damp environments, people often see it in basements, bathrooms, kitchens, and laundry rooms. It can also show up in crawl spaces where people have drainage problems, drier vents, or plumbing leaks.

Sometimes tiny flies start to appear and the homeowners wonder if the black mold attracted the flies, or if the flies caused the mold, or if the two are even connected at all.

There are several types of tiny flies that can develop in damp areas inside of homes. The location where the most flies are seen can be a clue to help identify them. It will also help when it is time to eliminate them.

Fungus Gnats

fungus gnat
Image credit:

Fungus gnats are tiny flies. They can be as small as 1/32″ long. They may be black, brown, or even yellow. They usually have very long legs, so they can resemble tiny mosquitoes. These flies commonly develop in the damp soil of potted plants. However they can also develop in animal droppings and fungus.

If they are breeding in a flowerpot, they are probably fungus gnats. Letting the soil dry will get rid of the flies. Putting the plant outside may speed up the drying.

Drain Flies

Moth flies, also known as drain flies and filter flies, usually develop in slimy residue inside of drainpipes. They are tiny flies, usually less than ¼” long. Their hairy wings and body make them look like tiny moths.

Drain Fly

Image credit: Matt Bertone, NC State

Phorid Flies

phorid fly or humpbacked fly
Image credit: P. G. Koehler and J. L. Castner,

Phorid flies are also called scuttle flies because of the way they run around. Some people call them humpbacked flies because of their appearance. Depending on the species, these flies can be as small as 1/64″. They deposit their eggs in animal droppings, damp fungus, and even in leaking sewer pipes.

If the adult flies are hovering over a drain, they may be phorid or moth flies. This may be a sign that the drain is clogged or has a backup of organic material. Taking off the trap and cleaning the pipe thoroughly should solve this problem.

Fruit Flies

fruit fly small image
fruit fly

Fruit flies are also tiny flies. The most common ones are tan-colored with red eyes. Some people call them vinegar flies because they are common in kitchens. They are attracted to fermenting fruit or vegetables. The adults deposit their eggs in the fruit and the larvae develop there.

These tiny flies may appear where the black mold is, or they may be in another part of the home. It will be important to observe the flies. Locating their breeding site will be the key to eliminating them.

If they are fruit flies, it will be easy to throw away the infested fruit or vegetables.

If the flies have been breeding in animal droppings or residue at the bottom of the garbage can, it may take some detective work to find the source. It is important to be thorough because the problem will not go away until there is no place for the flies to deposit their eggs. After the breeding site is corrected, the adult flies can be eliminated with an aerosol spray for flying insects.

Many homeowners call on a pest control professional for help with black mold flies. These people can make the inspection, identify the source, and make any insecticide applications that are needed.

See a list of flies that are found around filth.

Learn how to deal with fly infestations.