Drain Fly (Moth Fly)

Natural Habitat

Damp, organic-rich environments such as sinks, drains, sewage systems, and compost piles.

Diet & Feeding

Larvae feed on the gelatinous film of bacteria, fungi, and organic matter (biofilm) in drains; adults primarily consume liquid carbohydrates or nectar.

Behavior Patterns

Weak flyers that often crawl or hop; they are most active at night and are frequently found resting on walls near plumbing fixtures. They lay eggs in the moist film inside pipes.

Risks & Benefits

While they do not bite or transmit diseases through stings, they can mechanically carry bacteria from sewage to food surfaces. Their presence often indicates a need for plumbing cleaning or repair.

Identified on: 2/13/2026