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Be careful

House fly

Musca domestica
Also called housefly, common house fly

House flies do not bite, but they land on garbage and animal waste and can carry germs to your food, so keep them off kitchen surfaces.

House fly, photo 1
Photo: bioshots_jm, CC0, via iNaturalist
Sizeabout 6–7 mm (1/4 inch) long
Where in the houseKitchen, living room, windows and walls, garage, outside near the house
WhenLate spring through early fall, peaking in hot summer weather.

Check these features

  1. Medium-sized dull gray fly
  2. Four thin black stripes running lengthwise on the back, just behind the head
  3. Large reddish-brown eyes
  4. Grayish or yellowish abdomen with a dark center line
  5. Wings held apart in a slight V at rest, not overlapping

Bites and stings

Does not bite people. The concern is germs: flies that have walked on garbage or animal waste can leave bacteria on food and counters. Throw out food flies have been crawling on for a long time, and wash surfaces they land on.

What to do

  1. Swat or trap flies indoors and cover any food that is out.
  2. Wash counters, tables and dishes flies have landed on with hot soapy water.
  3. Find and remove what is attracting or breeding them: overflowing trash, pet waste, compost, spoiled produce, or a dead animal.
  4. Use sticky fly traps or an indoor light trap placed well away from food prep areas, following the product label.

Look-alikes

Cluster flyCluster flies are a bit larger and darker, have golden hairs on the back, fold their wings flat over each other like closed scissors, and show up in fall and winter rather than summer.
Stable flyStable flies look almost the same but have a stiff, pointed beak sticking forward and bite people, usually around the ankles, while house flies have a soft sponge-like mouth and cannot bite.

Why it came inside

Adults fly in through open doors and torn screens, drawn by food smells, garbage and pet waste. They breed in moist decaying material such as garbage, compost, animal manure and spilled pet food, usually outdoors.

Keep it out

  • Keep window and door screens in good repair and doors closed.
  • Use trash cans with tight-fitting lids, bag garbage, and empty cans at least weekly.
  • Pick up pet waste in the yard promptly and keep compost away from doors.
  • Clean up spilled pet food and rinse recycling before storing it.

What helps

Links go to Amazon search results so you can compare current options. As an Amazon Associate I earn from qualifying purchases. Always follow the product label.

Screen repair kit

Patches or replaces torn window and door screens, one of the most common ways insects get in.

See options on Amazon
Door sweep

Closes the gap under an exterior door. If you can see daylight under the door, bugs can get in.

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Sticky traps

Flat glue traps set along walls and in corners show what is moving through and where. Place them where pets and children can't reach.

See options on Amazon
Bait stations

Enclosed baits work slowly as insects carry the bait back to where they hide. Don't spray near the baits, and follow the label.

See options on Amazon

Sources

  1. University of Florida IFAS Extension (EDIS)
  2. University of Minnesota Extension
  3. University of Maine Cooperative Extension
  4. Connecticut Agricultural Experiment Station (cluster fly comparison)

Checked October 18, 2026. Rating backed by 3 sources. How we rate danger.