If you’ve noticed tiny, fuzzy flies resting on your bathroom walls or hovering around kitchen sinks, you may be dealing with drain flies. Also known as moth flies or sewer flies, these insects are common in homes and are often mistaken for fruit flies. While they don’t usually bite or spread disease directly, their presence often signals excess moisture and organic buildup inside drains.
What Are Drain Flies?
Drain flies are very small insects, usually measuring only 2–5 mm in length. Their bodies and wings are covered with tiny hairs, giving them a fuzzy, moth-like appearance. They are weak fliers and typically stay close to the drains where they hatch.
Where Do They Come From?
Drain flies lay their eggs in the slimy organic material that builds up inside drains, pipes, floor drains, septic systems, and other damp areas. The larvae feed on bacteria, fungi, and decaying organic matter before developing into adults.
Common Places You’ll Find Them
• Bathroom sink drains
• Shower and bathtub drains
• Kitchen sinks
• Basement floor drains
• Laundry room drains
• Garbage disposals
• Air conditioner condensate lines
Adults are often seen resting on walls or ceilings near these areas, especially during the evening.
But why do they suddenly appear in large numbers? The answer often surprises homeowners.
