Drain Flies in NJ, NYC, and Eastern PA

Drain Fly Control in New Jersey, New York City, Philadelphia, Connecticut, and Delaware


What Do Drain Flies Look Like?
Size: Approximately a third of the size of common house flies, drain flies grow an average of 1/8 of an inch long.

Color: These flies can be black, gray, or brown in color.

Characteristics: Their alternative name, moth fly, comes from the fine, miniscule hairs covering their bodies, which give them a moth-like appearance. Drain flies have leaf-shaped wings with distinctive parallel veins, and they are tiny enough to fit through the holes in window screens that otherwise safeguard against insect infestations.

Call for service: (877) 250-3857


  • Drain flies are known by many names, including moth fly, filter fly, and sewage fly.
  • Though they do not bite or otherwise physically harm humans or plants, these flies breed in the buildup of gelatinous material found in drainage pipes and in sewage.
  • Their presence exposes individuals to a number of bacteria and pathogens.


What Do Drain Flies Eat?
Both larvae and adults feed on:

  • Sewage
  • Algae
  • Fungi
  • Other organic materials


Drain flies mature from eggs to larvae to pupae and then adults. Females lay between 10 and 200 eggs directly in the organic muck that collects in drains.

Once these eggs hatch, maggots begin feeding until they form a hard shell in which to pupate. After enough time passes, adults emerge.

Summer and spring weather is best suited to drain fly development, and the entire process takes between one and three weeks. Adults live an average of two weeks.


  • May notice tiny adult flies gathered in bathrooms, kitchens, or basements.
  • Look for collections of rainwater or drainage outdoors that may attract drain flies.
  • Be alert for thin, whitish-brown larvae collected around drains.

Problems Caused by Drain Flies

  • Unsanitary: Since they spend most of their time in drains and sewage, drain flies are filthy.
  • Bacteria: Though they are not associated with any specific diseases, they expose house residents to a variety of bacteria wherever they are present.
  • Pathogens: Where moth flies exist in large numbers, their disintegrating bodies form the pathogens that are responsible for bronchial asthma.
  • Nuisance: Drain flies are considered nuisance pests, as they gather in significant numbers, which can agitate people.

Signs of Infestation

The most apparent indication of an infestation is sighting adult moth flies in

  • Bathrooms
  • Kitchens
  • Basements
  • Wherever else drains are present

Since they are poor fliers, drain flies do not travel far during their two weeks of life.

Outdoor drainage sites should also be monitored for collections of the small flies.

Prevention Tips

  • Repair screens: Window screens and other standard preventative measures do not effectively combat the tiny flies.
  • Sanitation: The best way to avoid infestations of drain flies is to regularly sanitize all drain pipes in the home.

Tips for Removal from Home

  • Chemical: Though it is commonly offered as a solution to moth fly infestations, pouring bleach or boiling water down affected drains is not enough to eliminate the problem, as the gelatinous buildup will remain and continue to attract the insects.
  • Cleaning: To kill off existing flies and remove the possibility of future infestations, industrial drain cleaner and a hard bristle brush are necessary.

Still, the best and most effective solution is to call a professional pest control service to eradicate any present drain flies.

Learn more about Western’s comprehensive Home Pest Control Plans.

Call for service: (877) 250-3857