Drain Fly (or Moth Fly)

Natural Habitat

Damp environments, especially drains, sewers, septic tanks, and areas with decaying organic matter. They are commonly found in bathrooms and kitchens.

Diet & Feeding

Larvae feed on decaying organic matter, bacteria, fungi, and algae found in neglected drains and sewage. Adult flies are not known to feed significantly.

Behavior Patterns

Adult drain flies are weak, erratic flyers and are often found resting on walls near breeding sites. They are most active at dusk and dawn. Females lay eggs in gelatinous films of organic matter. Their life cycle from egg to adult is relatively short, typically 1-3 weeks depending on conditions.

Risks & Benefits

Potential risks include being a nuisance pest due to their presence. While generally not considered a public health risk, they can carry bacteria and other pathogens from their breeding sites and potentially transfer them to surfaces. There are no notable benefits to humans; in ecosystems, they contribute to the decomposition of organic matter, but their primary interaction with humans is as a pest.

Identified on: 9/18/2025